1
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Sakai Y, Shimizu T, Tsunekawa M, Hisamoto N, Matsumoto K. Rhotekin regulates axon regeneration through the talin-Vinculin-Vinexin axis in Caenorhabditis elegans. PLoS Genet 2023; 19:e1011089. [PMID: 38150455 PMCID: PMC10752531 DOI: 10.1371/journal.pgen.1011089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023] Open
Abstract
Axon regeneration requires actomyosin interaction, which generates contractile force and pulls the regenerating axon forward. In Caenorhabditis elegans, TLN-1/talin promotes axon regeneration through multiple down-stream events. One is the activation of the PAT-3/integrin-RHO-1/RhoA GTPase-LET-502/ROCK (Rho-associated coiled-coil kinase)-regulatory non-muscle myosin light-chain (MLC) phosphorylation signaling pathway, which is dependent on the MLC scaffolding protein ALP-1/ALP-Enigma. The other is mediated by the F-actin-binding protein DEB-1/vinculin and is independent of the MLC phosphorylation pathway. In this study, we identified the svh-7/rtkn-1 gene, encoding a homolog of the RhoA-binding protein Rhotekin, as a regulator of axon regeneration in motor neurons. However, we found that RTKN-1 does not function in the RhoA-ROCK-MLC phosphorylation pathway in the regulation of axon regeneration. We show that RTKN-1 interacts with ALP-1 and the vinculin-binding protein SORB-1/vinexin, and that SORB-1 acts with DEB-1 to promote axon regeneration. Thus, RTKN-1 links the DEB-1-SORB-1 complex to ALP-1 and physically connects phosphorylated MLC on ALP-1 to the actin cytoskeleton. These results suggest that TLN-1 signaling pathways coordinate MLC phosphorylation and recruitment of phosphorylated MLC to the actin cytoskeleton during axon regeneration.
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Affiliation(s)
- Yoshiki Sakai
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Tatsuhiro Shimizu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Mayuka Tsunekawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Naoki Hisamoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Kunihiro Matsumoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
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2
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Mura-Escorche G, Perdomo-Ramírez A, Ramos-Trujillo E, Trujillo-Frías CJ, Claverie-Martín F. Characterization of pre-mRNA Splicing Defects Caused by CLCN5 and OCRL Mutations and Identification of Novel Variants Associated with Dent Disease. Biomedicines 2023; 11:3082. [PMID: 38002082 PMCID: PMC10669864 DOI: 10.3390/biomedicines11113082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
Dent disease (DD) is an X-linked renal tubulopathy characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis and progressive renal failure. Two-thirds of cases are associated with inactivating variants in the CLCN5 gene (Dent disease 1, DD1) and a few present variants in the OCRL gene (Dent disease 2, DD2). The aim of the present study was to test the effect on the pre-mRNA splicing process of DD variants, described here or in the literature, and describe the clinical and genotypic features of thirteen unrelated patients with suspected DD. All patients presented tubular proteinuria, ten presented hypercalciuria and five had nephrolithiasis or nephrocalcinosis. CLCN5 and OCRL genes were analyzed by Sanger sequencing. Nine patients showed variants in CLCN5 and four in OCRL; eight of these were new. Bioinformatics tools were used to select fifteen variants with a potential effect on pre-mRNA splicing from our patients' group and from the literature, and were experimentally tested using minigene assays. Results showed that three exonic missense mutations and two intronic variants affect the mRNA splicing process. Our findings widen the genotypic spectrum of DD and provide insight into the impact of variants causing DD.
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Affiliation(s)
- Glorián Mura-Escorche
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
- Departamento de Medicina Interna, Dermatología y Psiquiatría, Facultad de Medicina, Universidad de la Laguna, 38071 Santa Cruz de Tenerife, Spain
| | - Ana Perdomo-Ramírez
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
| | - Elena Ramos-Trujillo
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
- Departamento de Medicina Física y Farmacología, Facultad de Medicina, Universidad de la Laguna, 38071 Santa Cruz de Tenerife, Spain
| | - Carmen Jane Trujillo-Frías
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
| | - Félix Claverie-Martín
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
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3
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Abstract
Phosphoinositides (PIs) are phospholipids derived from phosphatidylinositol. PIs are regulated via reversible phosphorylation, which is directed by the opposing actions of PI kinases and phosphatases. PIs constitute a minor fraction of the total cellular lipid pool but play pleiotropic roles in multiple aspects of cell biology. Genetic mutations of PI regulatory enzymes have been identified in rare congenital developmental syndromes, including ciliopathies, and in numerous human diseases, such as cancer and metabolic and neurological disorders. Accordingly, PI regulatory enzymes have been targeted in the design of potential therapeutic interventions for human diseases. Recent advances place PIs as central regulators of membrane dynamics within functionally distinct subcellular compartments. This brief review focuses on the emerging role PIs play in regulating cell signaling within the primary cilium and in directing transfer of molecules at interorganelle membrane contact sites and identifies new roles for PIs in subcellular spaces.
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Affiliation(s)
- Elizabeth Michele Davies
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Christina Anne Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Harald Alfred Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research. The Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway
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4
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Droubi A, Wallis C, Anderson KE, Rahman S, de Sa A, Rahman T, Stephens LR, Hawkins PT, Lowe M. The inositol 5-phosphatase INPP5B regulates B cell receptor clustering and signaling. J Cell Biol 2022; 221:e202112018. [PMID: 35878408 PMCID: PMC9351708 DOI: 10.1083/jcb.202112018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/27/2022] [Accepted: 07/05/2022] [Indexed: 11/22/2022] Open
Abstract
Upon antigen binding, the B cell receptor (BCR) undergoes clustering to form a signalosome that propagates downstream signaling required for normal B cell development and physiology. BCR clustering is dependent on remodeling of the cortical actin network, but the mechanisms that regulate actin remodeling in this context remain poorly defined. In this study, we identify the inositol 5-phosphatase INPP5B as a key regulator of actin remodeling, BCR clustering, and downstream signaling in antigen-stimulated B cells. INPP5B acts via dephosphorylation of the inositol lipid PI(4,5)P2 that in turn is necessary for actin disassembly, BCR mobilization, and cell spreading on immobilized surface antigen. These effects can be explained by increased actin severing by cofilin and loss of actin linking to the plasma membrane by ezrin, both of which are sensitive to INPP5B-dependent PI(4,5)P2 hydrolysis. INPP5B is therefore a new player in BCR signaling and may represent an attractive target for treatment of B cell malignancies caused by aberrant BCR signaling.
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Affiliation(s)
- Alaa Droubi
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Connor Wallis
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | | | - Saifur Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Aloka de Sa
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | | | | | - Martin Lowe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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5
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SdhA blocks disruption of the Legionella-containing vacuole by hijacking the OCRL phosphatase. Cell Rep 2021; 37:109894. [PMID: 34731604 PMCID: PMC8669613 DOI: 10.1016/j.celrep.2021.109894] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 07/27/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022] Open
Abstract
Legionella pneumophila grows intracellularly within a replication vacuole via action of Icm/Dot-secreted proteins. One such protein, SdhA, maintains the integrity of the vacuolar membrane, thereby preventing cytoplasmic degradation of bacteria. We show here that SdhA binds and blocks the action of OCRL (OculoCerebroRenal syndrome of Lowe), an inositol 5-phosphatase pivotal for controlling endosomal dynamics. OCRL depletion results in enhanced vacuole integrity and intracellular growth of a sdhA mutant, consistent with OCRL participating in vacuole disruption. Overexpressed SdhA alters OCRL function, enlarging endosomes, driving endosomal accumulation of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), and interfering with endosomal trafficking. SdhA interrupts Rab guanosine triphosphatase (GTPase)-OCRL interactions by binding to the OCRL ASPM-SPD2-Hydin (ASH) domain, without directly altering OCRL 5-phosphatase activity. The Legionella vacuole encompassing the sdhA mutant accumulates OCRL and endosomal antigen EEA1 (Early Endosome Antigen 1), consistent with SdhA blocking accumulation of OCRL-containing endosomal vesicles. Therefore, SdhA hijacking of OCRL is associated with blocking trafficking events that disrupt the pathogen vacuole.
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6
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Oltrabella F, Jackson-Crawford A, Yan G, Rixham S, Starborg T, Lowe M. IPIP27A cooperates with OCRL to support endocytic traffic in the zebrafish pronephric tubule. Hum Mol Genet 2021; 31:1183-1196. [PMID: 34673953 DOI: 10.1093/hmg/ddab307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 01/08/2023] Open
Abstract
Endocytosis is a fundamentally important process through which material is internalized into cells from the extracellular environment. In the renal proximal tubule, endocytosis of the abundant scavenger receptor megalin and its co-receptor cubilin play a vital role in retrieving low molecular weight proteins from the renal filtrate. Although we know much about megalin and its ligands, the machinery and mechanisms by which the receptor is trafficked through the endosomal system remain poorly defined. In this study, we show that Ipip27A, an interacting partner of the Lowe syndrome protein OCRL, is required for endocytic traffic of megalin within the proximal renal tubule of zebrafish larvae. Knockout of Ipip27A phenocopies the endocytic phenotype seen upon loss of OCRL, with a deficit in uptake of both fluid-phase and protein cargo, which is accompanied by a reduction in megalin abundance and altered endosome morphology. Rescue and co-depletion experiments indicate that Ipip27A functions together with OCRL to support proximal tubule endocytosis. The results therefore identify Ipip27A as a new player in endocytic traffic in the proximal tubule in vivo and support the view that defective endocytosis underlies the renal tubulopathy in Lowe syndrome and Dent-2 disease.
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Affiliation(s)
- Francesca Oltrabella
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Medical Scientific Liaison - Nephrology, Astellas Pharma, Via Dante, 20123 Milano, Italy
| | - Anthony Jackson-Crawford
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Department of Blood Sciences, Grange University Hospital, Llanyravon, Gwent, NP44 8YN
| | - Guanhua Yan
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Sarah Rixham
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Tobias Starborg
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Rosalind Franklin Institute, Harwell Campus, Didcot, OX11 0FA, UK
| | - Martin Lowe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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7
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Gianesello L, Arroyo J, Del Prete D, Priante G, Ceol M, Harris PC, Lieske JC, Anglani F. Genotype Phenotype Correlation in Dent Disease 2 and Review of the Literature: OCRL Gene Pleiotropism or Extreme Phenotypic Variability of Lowe Syndrome? Genes (Basel) 2021; 12:1597. [PMID: 34680992 PMCID: PMC8535715 DOI: 10.3390/genes12101597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
Dent disease is a rare X-linked renal tubulopathy due to CLCN5 and OCRL (DD2) mutations. OCRL mutations also cause Lowe syndrome (LS) involving the eyes, brain and kidney. DD2 is frequently described as a mild form of LS because some patients may present with extra-renal symptoms (ESs). Since DD2 is a rare disease and there are a low number of reported cases, it is still unclear whether it has a clinical picture distinct from LS. We retrospectively analyzed the phenotype and genotype of our cohort of 35 DD2 males and reviewed all published DD2 cases. We analyzed the distribution of mutations along the OCRL gene and evaluated the type and frequency of ES according to the type of mutation and localization in OCRL protein domains. The frequency of patients with at least one ES was 39%. Muscle findings are the most common ES (52%), while ocular findings are less common (11%). Analysis of the distribution of mutations revealed (1) truncating mutations map in the PH and linker domain, while missense mutations map in the 5-phosphatase domain, and only occasionally in the ASH-RhoGAP module; (2) five OCRL mutations cause both DD2 and LS phenotypes; (3) codon 318 is a DD2 mutational hot spot; (4) a correlation was found between the presence of ES and the position of the mutations along OCRL domains. DD2 is distinct from LS. The mutation site and the mutation type largely determine the DD2 phenotype.
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Affiliation(s)
- Lisa Gianesello
- Kidney Histomorphology and Molecular Biology Laboratory, Nephrology, Dialysis and Transplantation Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (L.G.); (D.D.P.); (G.P.); (M.C.)
| | - Jennifer Arroyo
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA; (J.A.); (P.C.H.); (J.C.L.)
| | - Dorella Del Prete
- Kidney Histomorphology and Molecular Biology Laboratory, Nephrology, Dialysis and Transplantation Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (L.G.); (D.D.P.); (G.P.); (M.C.)
| | - Giovanna Priante
- Kidney Histomorphology and Molecular Biology Laboratory, Nephrology, Dialysis and Transplantation Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (L.G.); (D.D.P.); (G.P.); (M.C.)
| | - Monica Ceol
- Kidney Histomorphology and Molecular Biology Laboratory, Nephrology, Dialysis and Transplantation Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (L.G.); (D.D.P.); (G.P.); (M.C.)
| | - Peter C. Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA; (J.A.); (P.C.H.); (J.C.L.)
| | - John C. Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA; (J.A.); (P.C.H.); (J.C.L.)
| | - Franca Anglani
- Kidney Histomorphology and Molecular Biology Laboratory, Nephrology, Dialysis and Transplantation Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (L.G.); (D.D.P.); (G.P.); (M.C.)
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8
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Sakakibara N, Ijuin T, Horinouchi T, Yamamura T, Nagano C, Okada E, Ishiko S, Aoto Y, Rossanti R, Ninchoji T, Awano H, Nagase H, Minamikawa S, Tanaka R, Matsuyama T, Nagatani K, Kamei K, Jinnouchi K, Ohtsuka Y, Oka M, Araki Y, Tanaka T, Harada MS, Igarashi T, Kitahara H, Morisada N, Nakamura SI, Okada T, Iijima K, Nozu K. Identification of novel OCRL isoforms associated with phenotypic differences between Dent disease-2 and Lowe syndrome. Nephrol Dial Transplant 2021; 37:262-270. [PMID: 34586410 DOI: 10.1093/ndt/gfab274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Although Lowe syndrome and Dent disease-2 are both caused by OCRL mutations, their clinical severities differ substantially, and their molecular mechanisms remain unclear. Truncating mutations in OCRL exons 1 through 7 lead to Dent disease-2, whereas those in exons 8 through 24 lead to Lowe syndrome. Herein, we identified the mechanism underlying the action of novel OCRL protein isoforms. METHODS mRNA samples extracted from cultured urine-derived cells from a healthy control and the Dent disease-2 patient were examined to detect the 5' end of the OCRL isoform. For protein expression and functional analysis, vectors containing (1) the full-length OCRL transcripts, (2) the isoform transcripts, and (3) transcripts with truncating mutations detected in Lowe syndrome and Dent disease-2 patients were transfected into HeLa cells. RESULTS We successfully cloned the novel isoform transcripts from OCRL exons 6-24, including the translation-initiation codons present in exon 8. In vitro protein-expression analysis detected proteins of two different sizes (105 and 80 kDa) translated from full-length OCRL, whereas only one protein (80 kDa) was found from the isoform and Dent disease-2 variants. No protein expression was observed for the Lowe syndrome variants. The isoform enzyme activity was equivalent to that of full-length OCRL; the Dent disease-2 variants retained > 50% enzyme activity, whereas the Lowe syndrome variants retained < 20% activity. CONCLUSIONS We elucidated the molecular mechanism underlying the two different phenotypes in OCRL-related diseases; the functional OCRL isoform translated starting at exon 8 was associated with this mechanism.
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Affiliation(s)
- Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Ijuin
- Division of Biochemistry, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Department of Nephrology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Ninchoji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ryojiro Tanaka
- Department of Nephrology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
| | | | - Koji Nagatani
- Department of Pediatrics, Uwajima City Hospital, Uwajima, Japan
| | - Koichi Kamei
- Division of Nephrology and Rheumatology, National Center for Child Health and Development, Tokyo, Japan
| | - Kumiko Jinnouchi
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Yasufumi Ohtsuka
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Masafumi Oka
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Yoshinori Araki
- Department of Pediatrics, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan
| | - Toju Tanaka
- Department of Pediatrics, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan
| | - Mari S Harada
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Toru Igarashi
- Department of Pediatrics, Nippon Medical School Hospital, Tokyo, Japan
| | - Hikaru Kitahara
- Department of Pediatrics, Osaka Medical College, Takatsuki, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
| | - Shun-Ichi Nakamura
- Division of Biochemistry, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Taro Okada
- Division of Biochemistry, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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9
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Maxson ME, Sarantis H, Volchuk A, Brumell JH, Grinstein S. Rab5 regulates macropinocytosis by recruiting the inositol 5-phosphatases OCRL and Inpp5b that hydrolyse PtdIns(4,5)P2. J Cell Sci 2021; 134:237783. [PMID: 33722976 DOI: 10.1242/jcs.252411] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/25/2021] [Indexed: 01/09/2023] Open
Abstract
Rab5 is required for macropinosome formation, but its site and mode of action remain unknown. We report that Rab5 acts at the plasma membrane, downstream of ruffling, to promote macropinosome sealing and scission. Dominant-negative Rab5, which obliterates macropinocytosis, had no effect on the development of membrane ruffles. However, Rab5-containing vesicles were recruited to circular membrane ruffles, and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent endomembrane fusion was necessary for the completion of macropinocytosis. This fusion event coincided with the disappearance of PtdIns(4,5)P2 that accompanies macropinosome closure. Counteracting the depletion of PtdIns(4,5)P2 by expression of phosphatidylinositol-4-phosphate 5-kinase impaired macropinosome formation. Importantly, we found that the removal of PtdIns(4,5)P2 is dependent on Rab5, through the Rab5-mediated recruitment of the inositol 5-phosphatases OCRL and Inpp5b, via APPL1. Knockdown of OCRL and Inpp5b, or APPL1, prevented macropinosome closure without affecting ruffling. We therefore propose that Rab5 is essential for the clearance of PtdIns(4,5)P2 needed to complete the scission of macropinosomes or to prevent their back-fusion with the plasmalemma.
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Affiliation(s)
- Michelle E Maxson
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Helen Sarantis
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Allen Volchuk
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - John H Brumell
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
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10
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Yan Y, Liu S, Hu C, Xie C, Zhao L, Wang S, Zhang W, Cheng Z, Gao J, Fu X, Yang Z, Wang X, Zhang J, Lin L, Shi A. RTKN-1/Rhotekin shields endosome-associated F-actin from disassembly to ensure endocytic recycling. J Cell Biol 2021; 220:211976. [PMID: 33844824 PMCID: PMC8047894 DOI: 10.1083/jcb.202007149] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/22/2021] [Accepted: 03/10/2021] [Indexed: 12/15/2022] Open
Abstract
Cargo sorting and the subsequent membrane carrier formation require a properly organized endosomal actin network. To better understand the actin dynamics during endocytic recycling, we performed a genetic screen in C. elegans and identified RTKN-1/Rhotekin as a requisite to sustain endosome-associated actin integrity. Loss of RTKN-1 led to a prominent decrease in actin structures and basolateral recycling defects. Furthermore, we showed that the presence of RTKN-1 thwarts the actin disassembly competence of UNC-60A/cofilin. Consistently, in RTKN-1–deficient cells, UNC-60A knockdown replenished actin structures and alleviated the recycling defects. Notably, an intramolecular interaction within RTKN-1 could mediate the formation of oligomers. Overexpression of an RTKN-1 mutant form that lacks self-binding capacity failed to restore actin structures and recycling flow in rtkn-1 mutants. Finally, we demonstrated that SDPN-1/Syndapin acts to direct the recycling endosomal dwelling of RTKN-1 and promotes actin integrity there. Taken together, these findings consolidated the role of SDPN-1 in organizing the endosomal actin network architecture and introduced RTKN-1 as a novel regulatory protein involved in this process.
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Affiliation(s)
- Yanling Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shuai Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Can Hu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chaoyi Xie
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Linyue Zhao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shimin Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wenjuan Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zihang Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jinghu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xin Fu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhenrong Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xianghong Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jing Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Long Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Cell Architecture Research Institute, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Cell Architecture Research Institute, Huazhong University of Science and Technology, Wuhan, Hubei, China
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11
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Ramadesikan S, Skiba L, Lee J, Madhivanan K, Sarkar D, De La Fuente A, Hanna CB, Terashi G, Hazbun T, Kihara D, Aguilar RC. Genotype & phenotype in Lowe Syndrome: specific OCRL1 patient mutations differentially impact cellular phenotypes. Hum Mol Genet 2021; 30:198-212. [PMID: 33517444 DOI: 10.1093/hmg/ddab025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/15/2020] [Accepted: 01/08/2021] [Indexed: 12/26/2022] Open
Abstract
Lowe Syndrome (LS) is a lethal genetic disorder caused by mutations in the OCRL1 gene which encodes the lipid 5' phosphatase Ocrl1. Patients exhibit a characteristic triad of symptoms including eye, brain and kidney abnormalities with renal failure as the most common cause of premature death. Over 200 OCRL1 mutations have been identified in LS, but their specific impact on cellular processes is unknown. Despite observations of heterogeneity in patient symptom severity, there is little understanding of the correlation between genotype and its impact on phenotype. Here, we show that different mutations had diverse effects on protein localization and on triggering LS cellular phenotypes. In addition, some mutations affecting specific domains imparted unique characteristics to the resulting mutated protein. We also propose that certain mutations conformationally affect the 5'-phosphatase domain of the protein, resulting in loss of enzymatic activity and causing common and specific phenotypes (a conformational disease scenario). This study is the first to show the differential effect of patient 5'-phosphatase mutations on cellular phenotypes and introduces a conformational disease component in LS. This work provides a framework that explains symptom heterogeneity and can help stratify patients as well as to produce a more accurate prognosis depending on the nature and location of the mutation within the OCRL1 gene.
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Affiliation(s)
- Swetha Ramadesikan
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Lisette Skiba
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jennifer Lee
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | - Daipayan Sarkar
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | - Claudia B Hanna
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Genki Terashi
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Tony Hazbun
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Daisuke Kihara
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.,Department of Computer Science, Purdue University, West Lafayette, IN 47907, USA
| | - R Claudio Aguilar
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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12
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Festa BP, Berquez M, Nieri D, Luciani A. Endolysosomal Disorders Affecting the Proximal Tubule of the Kidney: New Mechanistic Insights and Therapeutics. Rev Physiol Biochem Pharmacol 2021; 185:233-257. [PMID: 33649992 DOI: 10.1007/112_2020_57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Epithelial cells that line the proximal tubule of the kidney rely on an intertwined ecosystem of vesicular membrane trafficking pathways to ensure the reabsorption of essential nutrients. To function effectively and to achieve homeostasis, these specialized cells require the sorting and recycling of a wide array of cell surface proteins within the endolysosomal network, including signaling receptors, nutrient transporters, ion channels, and polarity markers. The dysregulation of the endolysosomal system can lead to a generalized proximal tubule dysfunction, ultimately causing severe metabolic complications and kidney disease.In this chapter, we highlight the biological functions of the genes that code endolysosomal proteins from the perspective of understanding - and potentially reversing - the pathophysiology of endolysosomal disorders affecting the proximal tubule of the kidney. These insights might ultimately lead to potential treatments for currently intractable diseases and transform our ability to regulate kidney homeostasis and health.
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Affiliation(s)
- Beatrice Paola Festa
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Marine Berquez
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Daniela Nieri
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Alessandro Luciani
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland.
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13
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Perdomo-Ramirez A, Antón-Gamero M, Rizzo DS, Trindade A, Ramos-Trujillo E, Claverie-Martin F. Two new missense mutations in the protein interaction ASH domain of OCRL1 identified in patients with Lowe syndrome. Intractable Rare Dis Res 2020; 9:222-228. [PMID: 33139981 PMCID: PMC7586875 DOI: 10.5582/irdr.2020.03092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The oculocerebrorenal syndrome of Lowe is a rare X-linked disease characterized by congenital cataracts, proximal renal tubulopathy, muscular hypotonia and mental impairment. This disease is caused by mutations in the OCRL gene encoding membrane bound inositol polyphosphate 5-phosphatase OCRL1. Here, we examined the OCRL gene of two Lowe syndrome patients and report two new missense mutations that affect the ASH domain involved in protein-protein interactions. Genomic DNA was extracted from peripheral blood of two non-related patients and their relatives. Exons and flanking intronic regions of OCRL were analyzed by direct sequencing. Several bioinformatics tools were used to assess the pathogenicity of the variants. The three-dimensional structure of wild-type and mutant ASH domains was modeled using the online server SWISS-MODEL. Clinical features suggesting the diagnosis of Lowe syndrome were observed in both patients. Genetic analysis revealed two novel missense variants, c.1907T>A (p.V636E) and c.1979A>C (p.H660P) in exon 18 of the OCRL gene confirming the clinical diagnosis in both cases. Variant c.1907T>A (p.V636E) was inherited from the patient's mother, while variant c.1979A>C (p.H660P) seems to have originated de novo. Analysis with bioinformatics tools indicated that both variants are pathogenic. Both amino acid changes affect the structure of the OCRL1 ASH domain. In conclusion, the identification of two novel missense mutations located in the OCRL1 ASH domain may shed more light on the functional importance of this domain. We suggest that p.V636E and p.H660P cause Lowe syndrome by disrupting the interaction of OCRL1 with other proteins or by impairing protein stability.
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Affiliation(s)
- Ana Perdomo-Ramirez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | | | | | - Amelia Trindade
- Departamento de Medicina, Universidade Federal de Sao Carlos, Sao Paulo, Brazil
| | - Elena Ramos-Trujillo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Felix Claverie-Martin
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
- Address correspondence to:Félix Claverie-Martín, Unidad de Investigación, Hospital Nuestra Señora de Candelaria, Carretera del Rosario 145, 38010 Santa Cruz de Tenerife, Spain. E-mail:
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14
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Gianesello L, Del Prete D, Anglani F, Calò LA. Genetics and phenotypic heterogeneity of Dent disease: the dark side of the moon. Hum Genet 2020; 140:401-421. [PMID: 32860533 PMCID: PMC7889681 DOI: 10.1007/s00439-020-02219-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/20/2020] [Indexed: 12/18/2022]
Abstract
Dent disease is a rare genetic proximal tubulopathy which is under-recognized. Its phenotypic heterogeneity has led to several different classifications of the same disorder, but it is now widely accepted that the triad of symptoms low-molecular-weight proteinuria, hypercalciuria and nephrocalcinosis/nephrolithiasis are pathognomonic of Dent disease. Although mutations on the CLCN5 and OCRL genes are known to cause Dent disease, no such mutations are found in about 25–35% of cases, making diagnosis more challenging. This review outlines current knowledge regarding Dent disease from another perspective. Starting from the history of Dent disease, and reviewing the clinical details of patients with and without a genetic characterization, we discuss the phenotypic and genetic heterogeneity that typifies this disease. We focus particularly on all those confounding clinical signs and symptoms that can lead to a misdiagnosis. We also try to shed light on a concealed aspect of Dent disease. Although it is a proximal tubulopathy, its misdiagnosis may lead to patients undergoing kidney biopsy. In fact, some individuals with Dent disease have high-grade proteinuria, with or without hematuria, as in the clinical setting of glomerulopathy, or chronic kidney disease of uncertain origin. Although glomerular damage is frequently documented in Dent disease patients’ biopsies, there is currently no reliable evidence of renal biopsy being of either diagnostic or prognostic value. We review published histopathology reports of tubular and glomerular damage in these patients, and discuss current knowledge regarding the role of CLCN5 and OCRL genes in glomerular function.
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Affiliation(s)
- Lisa Gianesello
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
| | - Dorella Del Prete
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
| | - Franca Anglani
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy.
| | - Lorenzo A Calò
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
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15
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Ates KM, Wang T, Moreland T, Veeranan-Karmegam R, Ma M, Jeter C, Anand P, Wenzel W, Kim HG, Wolfe LA, Stephen J, Adams DR, Markello T, Tifft CJ, Settlage R, Gahl WA, Gonsalvez GB, Malicdan MC, Flanagan-Steet H, Pan YA. Deficiency in the endocytic adaptor proteins PHETA1/2 impairs renal and craniofacial development. Dis Model Mech 2020; 13:dmm041913. [PMID: 32152089 PMCID: PMC7272357 DOI: 10.1242/dmm.041913] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/27/2020] [Indexed: 12/20/2022] Open
Abstract
A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the in vivo functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain-containing endocytic trafficking adaptor 1 and 2 (PHETA1/2; also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of OCRL, the causative gene for Lowe syndrome. Here, we conducted the first study of PHETA1/2 in vivo, utilizing the zebrafish system. We found that impairment of both zebrafish orthologs, pheta1 and pheta2, disrupted endocytosis and ciliogenesis in renal tissues. In addition, pheta1/2 mutant animals exhibited reduced jaw size and delayed chondrocyte differentiation, indicating a role in craniofacial development. Deficiency of pheta1/2 resulted in dysregulation of cathepsin K, which led to an increased abundance of type II collagen in craniofacial cartilages, a marker of immature cartilage extracellular matrix. Cathepsin K inhibition rescued the craniofacial phenotypes in the pheta1/2 double mutants. The abnormal renal and craniofacial phenotypes in the pheta1/2 mutant animals were consistent with the clinical presentation of a patient with a de novo arginine (R) to cysteine (C) variant (R6C) of PHETA1. Expressing the patient-specific variant in zebrafish exacerbated craniofacial deficits, suggesting that the R6C allele acts in a dominant-negative manner. Together, these results provide insights into the in vivo roles of PHETA1/2 and suggest that the R6C variant is contributory to the pathogenesis of disease in the patient.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Kristin M Ates
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
| | - Tong Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Trevor Moreland
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | | | - Manxiu Ma
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
| | - Chelsi Jeter
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Priya Anand
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Hyung-Goo Kim
- Neurological Disorder Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Lynne A Wolfe
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshi Stephen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - David R Adams
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas Markello
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cynthia J Tifft
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert Settlage
- Advanced Research Computing Unit, Division of Information Technology, Virginia Tech, Blacksburg, VA 24060, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
- National Institutes of Health Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Graydon B Gonsalvez
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - May Christine Malicdan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
- National Institutes of Health Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Y Albert Pan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
- Department of Psychiatry and Behavioral Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
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16
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Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics. Cells 2020; 9:cells9040835. [PMID: 32244264 PMCID: PMC7226772 DOI: 10.3390/cells9040835] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/22/2020] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed.
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17
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Festa BP, Berquez M, Gassama A, Amrein I, Ismail HM, Samardzija M, Staiano L, Luciani A, Grimm C, Nussbaum RL, De Matteis MA, Dorchies OM, Scapozza L, Wolfer DP, Devuyst O. OCRL deficiency impairs endolysosomal function in a humanized mouse model for Lowe syndrome and Dent disease. Hum Mol Genet 2020; 28:1931-1946. [PMID: 30590522 PMCID: PMC6548226 DOI: 10.1093/hmg/ddy449] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/09/2018] [Accepted: 12/20/2018] [Indexed: 11/29/2022] Open
Abstract
Mutations in OCRL encoding the inositol polyphosphate 5-phosphatase OCRL (Lowe oculocerebrorenal syndrome protein) disrupt phosphoinositide homeostasis along the endolysosomal pathway causing dysfunction of the cells lining the kidney proximal tubule (PT). The dysfunction can be isolated (Dent disease 2) or associated with congenital cataracts, central hypotonia and intellectual disability (Lowe syndrome). The mechanistic understanding of Dent disease 2/Lowe syndrome remains scarce due to limitations of animal models of OCRL deficiency. Here, we investigate the role of OCRL in Dent disease 2/Lowe syndrome by using OcrlY/− mice, where the lethal deletion of the paralogue Inpp5b was rescued by human INPP5B insertion, and primary culture of proximal tubule cells (mPTCs) derived from OcrlY/− kidneys. The OcrlY/− mice show muscular defects with dysfunctional locomotricity and present massive urinary losses of low-molecular-weight proteins and albumin, caused by selective impairment of receptor-mediated endocytosis in PT cells. The latter was due to accumulation of phosphatidylinositol 4,5–bisphosphate PI(4,5)P2 in endolysosomes, driving local hyper-polymerization of F-actin and impairing trafficking of the endocytic LRP2 receptor, as evidenced in OcrlY/− mPTCs. The OCRL deficiency was also associated with a disruption of the lysosomal dynamic and proteolytic activity. Partial convergence of disease-pathways and renal phenotypes observed in OcrlY/− and Clcn5Y/− mice suggest shared mechanisms in Dent diseases 1 and 2. These studies substantiate the first mouse model of Lowe syndrome and give insights into the role of OCRL in cellular trafficking of multiligand receptors. These insights open new avenues for therapeutic interventions in Lowe syndrome and Dent disease.
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Affiliation(s)
| | - Marine Berquez
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Alkaly Gassama
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Irmgard Amrein
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Department of Health Sciences and Technology, ETH Zurich, Institute of Human Movement Sciences and Sport, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Hesham M Ismail
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Leopoldo Staiano
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | | | - Christian Grimm
- Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.,Lab for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Robert L Nussbaum
- Department of Medicine and Institute of Human Genetics, University of California, San Francisco, CA, USA.,Invitae Corporation, San Francisco, CA, USA
| | | | - Olivier M Dorchies
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - Leonardo Scapozza
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - David Paul Wolfer
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Department of Health Sciences and Technology, ETH Zurich, Institute of Human Movement Sciences and Sport, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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18
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Acosta-Tapia N, Galindo JF, Baldiris R. Insights into the Effect of Lowe Syndrome-Causing Mutation p.Asn591Lys of OCRL-1 through Protein-Protein Interaction Networks and Molecular Dynamics Simulations. J Chem Inf Model 2020; 60:1019-1027. [PMID: 31967472 DOI: 10.1021/acs.jcim.9b01077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inositol polyphosphate 5-phosphatase (OCRL-1) participates in the regulation of multiple cellular processes, through the conversion of phosphatidylinositol 4,5-phosphate to phosphatidylinositol 4-phosphate. Mutations in this protein are related to Lowe syndrome (LS) and Dent-2 disease. In this study, the impact of Lowe syndrome mutations on the interactions of OCRL-1 with other proteins was evaluated through bioinformatic and computational approaches. In the functional analysis of the interaction network of the proteins, we found that the terms of gene ontology (GO) of greater significance were related to the intracellular transport of proteins, the signal transduction mediated by small G proteins and vesicles associated with the Golgi apparatus. From the proteins present in the GO terms of greater significance Rab8a was selected because its interaction facilitates the intracellular distribution of OCRL-1. The mutation p.Asn591Lys, present in the interaction domain of OCRL-1 and Rab8a, was studied using molecular dynamics. The molecular dynamics analysis showed that the presence of this mutation causes changes in the positional fluctuations of the amino acids and affects the flexibility of the protein making the interaction with Rab8a weaker. Rab proteins establish some specific interactions, which are important for the intracellular localization of OCRL-1; therefore, our findings suggest that the phenotype observed in patients with LS, in this case, is due to the destabilizing effect of p.Asn591Lys affecting the localization of OCRL-1 and indirectly its 5-phosphatase activity in the Golgi apparatus, endosomes, and cilia.
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Affiliation(s)
- Natali Acosta-Tapia
- Programa de Biologı́a, Facultad de Ciencias Exactas y Naturales , Universidad de Cartagena , Cartagena de Indias , Colombia.,Grupo de Investigación CIPTEC, Facultad de Ingenierı́a , Fundación Universitaria Tecnológico Comfenalco , Cartagena de Indias 130015 , Colombia
| | - Johan Fabian Galindo
- Departamento de Quı́mica , Universidad Nacional de Colombia , Bogotá 111321 , Colombia
| | - Rosa Baldiris
- Programa de Biologı́a, Facultad de Ciencias Exactas y Naturales , Universidad de Cartagena , Cartagena de Indias , Colombia.,Grupo de Investigación CIPTEC, Facultad de Ingenierı́a , Fundación Universitaria Tecnológico Comfenalco , Cartagena de Indias 130015 , Colombia
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19
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Zheng B, Chen Q, Wang C, Zhou W, Chen Y, Ding G, Jia Z, Zhang A, Huang S. Whole-genome sequencing revealed an interstitial deletion encompassing OCRL and SMARCA1 gene in a patient with Lowe syndrome. Mol Genet Genomic Med 2019; 7:e876. [PMID: 31376231 PMCID: PMC6732312 DOI: 10.1002/mgg3.876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 06/19/2019] [Accepted: 07/01/2019] [Indexed: 12/13/2022] Open
Abstract
Background Lowe syndrome is a rare X‑linked syndrome that is characterized by involvement of the eyes, central nervous system, and kidneys. The aim of the present study was to determine the molecular basis of four patients with congenital cataract, infantile congenital hypotonia, and proximal renal tubular defect. Methods Four children who met the clinical manifestations of Lowe syndrome were enrolled in this study. Patients’ clinical information on eyes, central nervous system, kidneys, and family histories, etc., were reviewed and analyzed. After obtaining informed consent, we performed a mutation analysis of OCRL gene using direct sequencing. Because of failure of PCR amplification, low coverage shortread whole genome sequencing (CNVseq) analysis was performed on one proband. Real‐time PCR was subsequently performed to confirm the CNV that was detected from the CNVseq results. Results We identified three OCRL allelic variants, including two novel missense mutations (c.1423C>T/p.Pro475Ser, c.1502T>G/p.Ile501Ser) and one recurrent nonsense mutation (c.2464C>T/p.Arg822Ter). Various bioinformatic tools revealed scores associated with potential pathogenic effects for the two missense variants, and protein alignments revealed that both variants affected an amino acid highly conserved among species. Since deletion of the entire gene was suspected in a patient, CNVseq was used, identifying an interstitial deletion to approximately 190 kb, encompassing OCRL, and SMARCA1 gene. Moreover, the hemizygous CNV was confirmed by qPCR. Reviewing another case reported in the literature, we found that the deletion of OCRL and nearby genes may contribute to a more severe phenotype and premature death. Conclusions This is the first report of an interstitial deletion encompassing OCRL and SMARCA1 gene in Lowe syndrome. Our results expand the spectrum of mutations of the OCRL gene in Chinese population. Moreover, whole‐genome sequencing presents a comprehensive and reliable approach for detecting genomic copy number variation in patients or carriers in the family with rare inherited disorders.
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Affiliation(s)
- Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Qiuxia Chen
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Zhou
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ying Chen
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Guixia Ding
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Aihua Zhang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - SongMing Huang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
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20
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Luscher A, Fröhlich F, Barisch C, Littlewood C, Metcalfe J, Leuba F, Palma A, Pirruccello M, Cesareni G, Stagi M, Walther TC, Soldati T, De Camilli P, Swan LE. Lowe syndrome-linked endocytic adaptors direct membrane cycling kinetics with OCRL in Dictyostelium discoideum. Mol Biol Cell 2019; 30:2268-2282. [PMID: 31216233 PMCID: PMC6743453 DOI: 10.1091/mbc.e18-08-0510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 04/17/2019] [Accepted: 06/10/2019] [Indexed: 11/23/2022] Open
Abstract
Mutations of the inositol 5-phosphatase OCRL cause Lowe syndrome (LS), characterized by congenital cataract, low IQ, and defective kidney proximal tubule resorption. A key subset of LS mutants abolishes OCRL's interactions with endocytic adaptors containing F&H peptide motifs. Converging unbiased methods examining human peptides and the unicellular phagocytic organism Dictyostelium discoideum reveal that, like OCRL, the Dictyostelium OCRL orthologue Dd5P4 binds two proteins closely related to the F&H proteins APPL1 and Ses1/2 (also referred to as IPIP27A/B). In addition, a novel conserved F&H interactor was identified, GxcU (in Dictyostelium) and the Cdc42-GEF FGD1-related F-actin binding protein (Frabin) (in human cells). Examining these proteins in D. discoideum, we find that, like OCRL, Dd5P4 acts at well-conserved and physically distinct endocytic stations. Dd5P4 functions in coordination with F&H proteins to control membrane deformation at multiple stages of endocytosis and suppresses GxcU-mediated activity during fluid-phase micropinocytosis. We also reveal that OCRL/Dd5P4 acts at the contractile vacuole, an exocytic osmoregulatory organelle. We propose F&H peptide-containing proteins may be key modifiers of LS phenotypes.
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Affiliation(s)
- Alexandre Luscher
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Florian Fröhlich
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Caroline Barisch
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Clare Littlewood
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Joe Metcalfe
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Florence Leuba
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Anita Palma
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Michelle Pirruccello
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Gianni Cesareni
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Tobias C. Walther
- Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510
| | - Laura E. Swan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
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21
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Hansen SD, Huang WYC, Lee YK, Bieling P, Christensen SM, Groves JT. Stochastic geometry sensing and polarization in a lipid kinase-phosphatase competitive reaction. Proc Natl Acad Sci U S A 2019; 116:15013-15022. [PMID: 31278151 PMCID: PMC6660746 DOI: 10.1073/pnas.1901744116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Phosphorylation reactions, driven by competing kinases and phosphatases, are central elements of cellular signal transduction. We reconstituted a native eukaryotic lipid kinase-phosphatase reaction that drives the interconversion of phosphatidylinositol-4-phosphate [PI(4)P] and phosphatidylinositol-4,5-phosphate [PI(4,5)P2] on membrane surfaces. This system exhibited bistability and formed spatial composition patterns on supported membranes. In smaller confined regions of membrane, rapid diffusion ensures the system remains spatially homogeneous, but the final outcome-a predominantly PI(4)P or PI(4,5)P2 membrane composition-was governed by the size of the reaction environment. In larger confined regions, interplay between the reactions, diffusion, and confinement created a variety of differentially patterned states, including polarization. Experiments and kinetic modeling reveal how these geometric confinement effects arise from a mechanism based on stochastic fluctuations in the copy number of membrane-bound kinases and phosphatases. The underlying requirements for such behavior are unexpectedly simple and likely to occur in natural biological signaling systems.
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Affiliation(s)
- Scott D Hansen
- Department of Chemistry, University of California, Berkeley, CA 94720;
- California Institute for Quantitative Biosciences, Berkeley, CA 94720
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
| | - William Y C Huang
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Young Kwang Lee
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Peter Bieling
- California Institute for Quantitative Biosciences, Berkeley, CA 94720
| | | | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, CA 94720;
- California Institute for Quantitative Biosciences, Berkeley, CA 94720
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22
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Voth KA, Chung IYW, van Straaten K, Li L, Boniecki MT, Cygler M. The structure of Legionella effector protein LpnE provides insights into its interaction with Oculocerebrorenal syndrome of Lowe (OCRL) protein. FEBS J 2018; 286:710-725. [PMID: 30479037 DOI: 10.1111/febs.14710] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/18/2018] [Accepted: 11/23/2018] [Indexed: 12/17/2022]
Abstract
Legionella pneumophila is a freshwater bacterium that replicates in predatory amoeba and alveolar macrophage. The ability of L. pneumophila to thrive in eukaryotic host cells is conferred by the Legionella containing vacuole (LCV). Formation and intracellular trafficking of the LCV are governed by an arsenal of effector proteins, many of which are secreted by the Icm/Dot Type 4 Secretion System. One such effector, known as LpnE (L. pneumophila Entry), has been implicated in facilitating bacterial entry into host cells, LCV trafficking, and substrate translocation. LpnE belongs to a subfamily of tetratricopeptide repeat proteins known as Sel1-like repeats (SLRs). All eight of the predicted SLRs in LpnE are required to promote host cell invasion. Herein, we report that LpnE(1-375) localizes to cis-Golgi in HEK293 cells via its signal peptide (aa 1-22). We further verify the interaction of LpnE(73-375) and LpnE(22-375) with Oculocerebrorenal syndrome of Lowe protein (OCRL) residues 10-208, restricting the known interacting residues for both proteins. To further characterize the SLR region of LpnE, we solved the crystal structure of LpnE(73-375) to 1.75Å resolution. This construct comprises all SLRs, which are arranged in a superhelical fold. The α-helices forming the inner concave surface of the LpnE superhelix suggest a potential protein-protein interaction interface. DATABASE: Coordinates and structure factors were deposited in the Protein Data Bank with the accession number 6DEH.
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Affiliation(s)
- Kevin A Voth
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
| | - Ivy Yeuk Wah Chung
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
| | - Karin van Straaten
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
| | - Lei Li
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
| | - Michal T Boniecki
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
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23
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Abstract
Phosphoinositides (PIs) play pivotal roles in the regulation of many biological processes. The quality and quantity of PIs is regulated in time and space by the activity of PI kinases and PI phosphatases. The number of PI-metabolizing enzymes exceeds the number of PIs with, in many cases, more than one enzyme controlling the same biochemical step. This would suggest that the PI system has an intrinsic ability to buffer and compensate for the absence of a specific enzymatic activity. However, there are several examples of severe inherited human diseases caused by mutations in one of the PI enzymes, although other enzymes with the same activity are fully functional. The kidney depends strictly on PIs for physiological processes, such as cell polarization, filtration, solute reabsorption, and signal transduction. Indeed, alteration of the PI system in the kidney very often results in pathological conditions, both inherited and acquired. Most of the knowledge of the roles that PIs play in the kidney comes from the study of KO animal models for genes encoding PI enzymes and from the study of human genetic diseases, such as Lowe syndrome/Dent disease 2 and Joubert syndrome, caused by mutations in the genes encoding the PI phosphatases, OCRL and INPP5E, respectively.
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Affiliation(s)
- Leopoldo Staiano
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy .,University of Naples Federico II, 80131 Naples, Italy
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24
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Ramos AR, Ghosh S, Erneux C. The impact of phosphoinositide 5-phosphatases on phosphoinositides in cell function and human disease. J Lipid Res 2018; 60:276-286. [PMID: 30194087 DOI: 10.1194/jlr.r087908] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/01/2018] [Indexed: 02/06/2023] Open
Abstract
Phosphoinositides (PIs) are recognized as major signaling molecules in many different functions of eukaryotic cells. PIs can be dephosphorylated by multiple phosphatase activities at the 5-, 4-, and 3- positions. Human PI 5-phosphatases belong to a family of 10 members. Except for inositol polyphosphate 5-phosphatase A, they all catalyze the dephosphorylation of PI(4,5)P2 and/or PI(3,4,5)P3 at the 5- position. PI 5-phosphatases thus directly control the levels of PI(3,4,5)P3 and participate in the fine-tuning regulatory mechanisms of PI(3,4)P2 and PI(4,5)P2 Second messenger functions have been demonstrated for PI(3,4)P2 in invadopodium maturation and lamellipodia formation. PI 5-phosphatases can use several substrates on isolated enzymes, and it has been challenging to establish their real substrate in vivo. PI(4,5)P2 has multiple functions in signaling, including interacting with scaffold proteins, ion channels, and cytoskeleton proteins. PI 5-phosphatase isoenzymes have been individually implicated in human diseases, such as the oculocerebrorenal syndrome of Lowe, through mechanisms that include lipid control. Oncogenic and tumor-suppressive functions of PI 5-phosphatases have also been reported in different cell contexts. The mechanisms responsible for genetic diseases and for oncogenic or tumor-suppressive functions are not fully understood. The regulation of PI 5-phosphatases is thus crucial in understanding cell functions.
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Affiliation(s)
- Ana Raquel Ramos
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Somadri Ghosh
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Christophe Erneux
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, 1070 Brussels, Belgium
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25
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Quantitative Imaging Flow Cytometry of Legionella-Infected Dictyostelium Amoebae Reveals the Impact of Retrograde Trafficking on Pathogen Vacuole Composition. Appl Environ Microbiol 2018; 84:AEM.00158-18. [PMID: 29602783 DOI: 10.1128/aem.00158-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/27/2018] [Indexed: 01/15/2023] Open
Abstract
The ubiquitous environmental bacterium Legionella pneumophila survives and replicates within amoebae and human macrophages by forming a Legionella-containing vacuole (LCV). In an intricate process governed by the bacterial Icm/Dot type IV secretion system and a plethora of effector proteins, the nascent LCV interferes with a number of intracellular trafficking pathways, including retrograde transport from endosomes to the Golgi apparatus. Conserved retrograde trafficking components, such as the retromer coat complex or the phosphoinositide (PI) 5-phosphatase D. discoideum 5-phosphatase 4 (Dd5P4)/oculocerebrorenal syndrome of Lowe (OCRL), restrict intracellular replication of L. pneumophila by an unknown mechanism. Here, we established an imaging flow cytometry (IFC) approach to assess in a rapid, unbiased, and large-scale quantitative manner the role of retrograde-linked PI metabolism and actin dynamics in the LCV composition. Exploiting Dictyostelium discoideum genetics, we found that Dd5P4 modulates the acquisition of fluorescently labeled LCV markers, such as calnexin, the small GTPase Rab1 (but not Rab7 and Rab8), and retrograde trafficking components (Vps5, Vps26, Vps35). The actin-nucleating protein and retromer interactor WASH (Wiskott-Aldrich syndrome protein [WASP] and suppressor of cAMP receptor [SCAR] homologue) promotes the accumulation of Rab1 and Rab8 on LCVs. Collectively, our findings validate IFC for the quantitative and unbiased analysis of the pathogen vacuole composition and reveal the impact of retrograde-linked PI metabolism and actin dynamics on the LCV composition. The IFC approach employed here can be adapted for a molecular analysis of the pathogen vacuole composition of other amoeba-resistant pathogens.IMPORTANCELegionella pneumophila is an amoeba-resistant environmental bacterium which can cause a life-threatening pneumonia termed Legionnaires' disease. In order to replicate intracellularly, the opportunistic pathogen forms a protective compartment, the Legionella-containing vacuole (LCV). An in-depth analysis of the LCV composition and the complex process of pathogen vacuole formation is crucial for understanding the virulence of L. pneumophila Here, we established an imaging flow cytometry (IFC) approach to assess in a rapid, unbiased, and quantitative manner the accumulation of fluorescently labeled markers and probes on LCVs. Using IFC and L. pneumophila-infected Dictyostelium discoideum or defined mutant amoebae, a role for phosphoinositide (PI) metabolism, retrograde trafficking, and the actin cytoskeleton in the LCV composition was revealed. In principle, the powerful IFC approach can be used to analyze the molecular composition of any cellular compartment harboring bacterial pathogens.
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26
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Rosselli-Murai LK, Yates JA, Yoshida S, Bourg J, Ho KKY, White M, Prisby J, Tan X, Altemus M, Bao L, Wu ZF, Veatch SL, Swanson JA, Merajver SD, Liu AP. Loss of PTEN promotes formation of signaling-capable clathrin-coated pits. J Cell Sci 2018; 131:jcs.208926. [PMID: 29588397 DOI: 10.1242/jcs.208926] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 03/19/2018] [Indexed: 12/19/2022] Open
Abstract
Defective endocytosis and vesicular trafficking of signaling receptors has recently emerged as a multifaceted hallmark of malignant cells. Clathrin-coated pits (CCPs) display highly heterogeneous dynamics on the plasma membrane where they can take from 20 s to over 1 min to form cytosolic coated vesicles. Despite the large number of cargo molecules that traffic through CCPs, it is not well understood whether signaling receptors activated in cancer, such as epidermal growth factor receptor (EGFR), are regulated through a specific subset of CCPs. The signaling lipid phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3], which is dephosphorylated by phosphatase and tensin homolog (PTEN), is a potent tumorigenic signaling lipid. By using total internal reflection fluorescence microscopy and automated tracking and detection of CCPs, we found that EGF-bound EGFR and PTEN are enriched in a distinct subset of short-lived CCPs that correspond with clathrin-dependent EGF-induced signaling. We demonstrated that PTEN plays a role in the regulation of CCP dynamics. Furthermore, increased PI(3,4,5)P3 resulted in higher proportion of short-lived CCPs, an effect that recapitulates PTEN deletion. Altogether, our findings provide evidence for the existence of short-lived 'signaling-capable' CCPs.
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Affiliation(s)
| | - Joel A Yates
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sei Yoshida
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Julia Bourg
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan White
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julia Prisby
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinyu Tan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan Altemus
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA.,Cancer Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liwei Bao
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Zhi-Fen Wu
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sarah L Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Sofia D Merajver
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA .,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA .,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA.,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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27
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Bärlocher K, Welin A, Hilbi H. Formation of the Legionella Replicative Compartment at the Crossroads of Retrograde Trafficking. Front Cell Infect Microbiol 2017; 7:482. [PMID: 29226112 PMCID: PMC5706426 DOI: 10.3389/fcimb.2017.00482] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
Retrograde trafficking from the endosomal system through the Golgi apparatus back to the endoplasmic reticulum is an essential pathway in eukaryotic cells, serving to maintain organelle identity and to recycle empty cargo receptors delivered by the secretory pathway. Intracellular replication of several bacterial pathogens, including Legionella pneumophila, is restricted by the retrograde trafficking pathway. L. pneumophila employs the Icm/Dot type IV secretion system (T4SS) to form the replication-permissive Legionella-containing vacuole (LCV), which is decorated with multiple components of the retrograde trafficking machinery as well as retrograde cargo receptors. The L. pneumophila effector protein RidL is secreted by the T4SS and interferes with retrograde trafficking. Here, we review recent evidence that the LCV interacts with the retrograde trafficking pathway, discuss the possible sites of action and function of RidL in the retrograde route, and put forth the hypothesis that the LCV is an acceptor compartment of retrograde transport vesicles.
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Affiliation(s)
- Kevin Bärlocher
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Amanda Welin
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
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28
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Abstract
Lowe syndrome is an X-linked disease that is characterized by congenital cataracts, central hypotonia, intellectual disability and renal Fanconi syndrome. The disease is caused by mutations in OCRL, which encodes an inositol polyphosphate 5-phosphatase (OCRL) that acts on phosphoinositides - quantitatively minor constituents of cell membranes that are nonetheless pivotal regulators of intracellular trafficking. In this Review we summarize the considerable progress made over the past decade in understanding the cellular roles of OCRL in regulating phosphoinositide balance along the endolysosomal pathway, a fundamental system for the reabsorption of proteins and solutes by proximal tubular cells. We discuss how studies of OCRL have led to important discoveries about the basic mechanisms of membrane trafficking and describe the key features and limitations of the currently available animal models of Lowe syndrome. Mutations in OCRL can also give rise to a milder pathology, Dent disease 2, which is characterized by renal Fanconi syndrome in the absence of extrarenal pathologies. Understanding how mutations in OCRL give rise to two clinical entities with differing extrarenal manifestations represents an opportunity to identify molecular pathways that could be targeted to develop treatments for these conditions.
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29
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Ocular Pathology of Oculocerebrorenal Syndrome of Lowe: Novel Mutations and Genotype-Phenotype Analysis. Sci Rep 2017; 7:1442. [PMID: 28473699 PMCID: PMC5431454 DOI: 10.1038/s41598-017-01447-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/28/2017] [Indexed: 12/02/2022] Open
Abstract
Mutations in the OCRL1 gene result in the oculocerebrorenal syndrome of Lowe, with symptoms including congenital bilateral cataracts, glaucoma, renal failure, and neurological impairments. OCRL1 encodes an inositol polyphosphate 5-phosphatase which preferentially dephosphorylates phosphatidylinositide 4,5 bisphosphate (PI(4,5)P2). We have identified two novel mutations in two unrelated Lowe syndrome patients with congenital glaucoma. Novel deletion mutations are detected at c.739-742delAAAG in Lowe patient 1 and c.1595-1631del in Lowe patient 2. End stage glaucoma in patient 2 resulted in the enucleation of the eye, which on histology demonstrated corneal keloid, fibrous infiltration of the angle, ectropion uvea, retinal gliosis, and retinal ganglion cell loss. We measured OCRL protein levels in patient keratinocytes and found that Lowe 1 patient cells had significantly reduced OCRL protein as compared to the control keratinocytes. Genotype-phenotype correlation of OCRL1 mutations associated with congenital glaucoma revealed clustering of missense and deletion mutations in the 5-phosphatase domain and the RhoGAP-like domain. In conclusion, we report novel OCRL1 mutations in Lowe syndrome patients and the corresponding histopathologic analysis of one patient’s ocular pathology.
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30
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Shiozaki Y, Segawa H, Ohnishi S, Ohi A, Ito M, Kaneko I, Kido S, Tatsumi S, Miyamoto KI. Relationship between sodium-dependent phosphate transporter (NaPi-IIc) function and cellular vacuole formation in opossum kidney cells. THE JOURNAL OF MEDICAL INVESTIGATION 2017; 62:209-18. [PMID: 26399350 DOI: 10.2152/jmi.62.209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
NaPi-IIc/SLC34A3 is a sodium-dependent inorganic phosphate (Pi) transporter in the renal proximal tubules and its mutations cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). In the present study, we created a specific antibody for opossum SLC34A3, NaPi-IIc (oNaPi-IIc), and analyzed its localization and regulation in opossum kidney cells (a tissue culture model of proximal tubular cells). Immunoreactive oNaPi-IIc protein levels increased during the proliferative phase and decreased during differentiation. Moreover, stimulating cell growth upregulated oNaPi-IIc protein levels, whereas suppressing cell proliferation downregulated oNaPi-IIc protein levels. Immunocytochemistry revealed that endogenous and exogenous oNaPi-IIc proteins localized at the protrusion of the plasma membrane, which is a phosphatidylinositol 4,5-bisphosphate (PIP2) rich-membrane, and at the intracellular vacuolar membrane. Exogenous NaPi-IIc also induced cellular vacuoles and localized in the plasma membrane. The ability to form vacuoles is specific to electroneutral NaPi-IIc, and not electrogenic NaPi-IIa or NaPi-IIb. In addition, mutations of NaPi-IIc (S138F and R468W) in HHRH did not cause cellular PIP2-rich vacuoles. In conclusion, our data anticipate that NaPi-IIc may regulate PIP2 production at the plasma membrane and cellular vesicle formation.
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Affiliation(s)
- Yuji Shiozaki
- Department of Molecular Nutrition, University of Tokushima Graduate School
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31
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Yin MX, Catimel B, Gregory M, Condron M, Kapp E, Holmes AB, Burgess AW. Synthesis of an inositol hexakisphosphate (IP6) affinity probe to study the interactome from a colon cancer cell line. Integr Biol (Camb) 2016; 8:309-18. [PMID: 26840369 DOI: 10.1039/c5ib00264h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Inositol hexakisphosphate (InsP6 or IP6) is an important signalling molecule in vesicular trafficking, neurotransmission, immune responses, regulation of protein kinases and phosphatases, activation of ion channels, antioxidant functions and anticancer activities. An IP6 probe was synthesised from myo-inositol via a derivatised analogue, which was immobilised through a terminal amino group onto Dynabeads. Systematic analysis of the IP6 interactome has been performed using the IP6 affinity probe using cytosolic extracts from the LIM1215 colonic carcinoma cell line. LC/MS/MS analysis identified 77 proteins or protein complexes that bind to IP6 specifically, including AP-2 complex proteins and β-arrestins as well as a number of novel potential IP6 interacting proteins. Bioinformatic enrichment analysis of the IP6 interactome reinforced the concept that IP6 regulates a number of biological processes including cell cycle and division, signal transduction, intracellular protein transport, vesicle-mediated transport and RNA splicing.
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Affiliation(s)
- Meng-Xin Yin
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia
| | - Bruno Catimel
- Ludwig Institute for Cancer Research, Melbourne-Austin Branch, Olivia Newton-John Cancer & Wellness Centre, Studley Road, Heidelberg, Victoria 3084, Australia
| | - Mark Gregory
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia
| | - Melanie Condron
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia. and Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Eugene Kapp
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia. and Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Andrew B Holmes
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia
| | - Antony W Burgess
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia. and Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia and Department of Surgery, RMH, University of Melbourne, Parkville, Victoria 3052, Australia
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32
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Duran D, Jin SC, DeSpenza T, Nelson-Williams C, Cogal AG, Abrash EW, Harris PC, Lieske JC, Shimshak SJ, Mane S, Bilguvar K, DiLuna ML, Günel M, Lifton RP, Kahle KT. Digenic mutations of human OCRL paralogs in Dent's disease type 2 associated with Chiari I malformation. Hum Genome Var 2016; 3:16042. [PMID: 28018608 PMCID: PMC5143364 DOI: 10.1038/hgv.2016.42] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 10/21/2016] [Indexed: 02/06/2023] Open
Abstract
OCRL1 and its paralog INPP5B encode phosphatidylinositol 5-phosphatases that localize to the primary cilium and have roles in ciliogenesis. Mutations in OCRL1 cause the X-linked Dent disease type 2 (DD2; OMIM# 300555), characterized by low-molecular weight proteinuria, hypercalciuria, and the variable presence of cataracts, glaucoma and intellectual disability without structural brain anomalies. Disease-causing mutations in INPP5B have not been described in humans. Here, we report the case of an 11-year-old boy with short stature and an above-average IQ; severe proteinuria, hypercalciuria and osteopenia resulting in a vertebral compression fracture; and Chiari I malformation with cervico-thoracic syringohydromyelia requiring suboccipital decompression. Sequencing revealed a novel, de novo DD2-causing 462 bp deletion disrupting exon 3 of OCRL1 and a maternally inherited, extremely rare (ExAC allele frequency 8.4×10−6) damaging missense mutation in INPP5B (p.A51V). This mutation substitutes an evolutionarily conserved amino acid in the protein’s critical PH domain. In silico analyses of mutation impact predicted by SIFT, PolyPhen2, MetaSVM and CADD algorithms were all highly deleterious. Together, our findings report a novel association of DD2 with Chiari I malformation and syringohydromyelia, and document the effects of digenic mutation of human OCRL paralogs. These findings lend genetic support to the hypothesis that impaired ciliogenesis may contribute to the development of Chiari I malformation, and implicates OCRL-dependent PIP3 metabolism in this mechanism.
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Affiliation(s)
- Daniel Duran
- Department of Neurosurgery, Yale School of Medicine , New Haven, CT, USA
| | - Sheng Chih Jin
- Department of Genetics, Yale School of Medicine , New Haven, CT, USA
| | - Tyrone DeSpenza
- Department of Neurosurgery, Yale School of Medicine , New Haven, CT, USA
| | - Carol Nelson-Williams
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Andrea G Cogal
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine , Rochester, MN, USA
| | - Elizabeth W Abrash
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine , Rochester, MN, USA
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, MN, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, MN, USA; O'Brien Urology Research Center, Mayo Clinic College of Medicine, Rochester, MN, USA; Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Serena Je Shimshak
- Department of Neurosurgery, Yale School of Medicine , New Haven, CT, USA
| | - Shrikant Mane
- Yale Center for Genome Analysis, Yale School of Medicine, Yale University , New Haven, CT, USA
| | - Kaya Bilguvar
- Yale Center for Genome Analysis, Yale School of Medicine, Yale University , New Haven, CT, USA
| | - Michael L DiLuna
- Department of Neurosurgery, Yale School of Medicine , New Haven, CT, USA
| | - Murat Günel
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA; Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | | | - Kristopher T Kahle
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA; Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
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33
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Inoue K, Balkin DM, Liu L, Nandez R, Wu Y, Tian X, Wang T, Nussbaum R, De Camilli P, Ishibe S. Kidney Tubular Ablation of Ocrl/ Inpp5b Phenocopies Lowe Syndrome Tubulopathy. J Am Soc Nephrol 2016; 28:1399-1407. [PMID: 27895154 DOI: 10.1681/asn.2016080913] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 10/05/2016] [Indexed: 12/26/2022] Open
Abstract
Lowe syndrome and Dent disease are two conditions that result from mutations of the inositol 5-phosphatase oculocerebrorenal syndrome of Lowe (OCRL) and share the feature of impaired kidney proximal tubule function. Genetic ablation of Ocrl in mice failed to recapitulate the human phenotypes, possibly because of the redundant functions of OCRL and its paralog type 2 inositol polyphosphate-5-phosphatase (INPP5B). Germline knockout of both paralogs in mice results in early embryonic lethality. We report that kidney tubule-specific inactivation of Inpp5b on a global Ocrl-knockout mouse background resulted in low molecular weight proteinuria, phosphaturia, and acidemia. At the cellular level, we observed a striking impairment of clathrin-dependent and -independent endocytosis in proximal tubules, phenocopying what has been reported for Dent disease caused by mutations in the gene encoding endosomal proton-chloride exchange transporter 5. These results suggest that the functions of OCRL/INPP5B and proton-chloride exchange transporter 5 converge on shared mechanisms, the impairment of which has a dramatic effect on proximal tubule endocytosis.
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Affiliation(s)
| | - Daniel M Balkin
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut
| | - Lijuan Liu
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | - Ramiro Nandez
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut
| | - Yumei Wu
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | | | | | - Robert Nussbaum
- Department of Medicine and.,Institute of Human Genetics, University of California, San Francisco, California; and.,Howard Hughes Medical Institute, and
| | - Pietro De Camilli
- Cell Biology, .,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | - Shuta Ishibe
- Departments of Internal Medicine, .,Cellular and Molecular Physiology
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34
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Shi X, Yang J, Cui X, Huang J, Long Z, Zhou Y, Liu P, Tao L, Ruan Z, Xiao B, Zhang W, Li D, Dai K, Mao J, Xi X. Functional Effect of the Mutations Similar to the Cleavage during Platelet Activation at Integrin β3 Cytoplasmic Tail when Expressed in Mouse Platelets. PLoS One 2016; 11:e0166136. [PMID: 27851790 PMCID: PMC5112943 DOI: 10.1371/journal.pone.0166136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 10/24/2016] [Indexed: 12/31/2022] Open
Abstract
Previous studies in Chinese hamster ovary cells showed that truncational mutations of β3 at sites of F754 and Y759 mimicking calpain cleavage regulate integrin signaling. The roles of the sequence from F754 to C-terminus and the conservative N756ITY759 motif in platelet function have yet to be elaborated. Mice expressing β3 with F754 and Y759 truncations, or NITY deletion (β3-ΔTNITYRGT, β3-ΔRGT, or β3-ΔNITY) were established through transplanting the homozygous β3-deficient mouse bone marrow cells infected by the GFP tagged MSCV MigR1 retroviral vector encoding different β3 mutants into lethally radiated wild-type mice. The platelets were harvested for soluble fibrinogen binding and platelet spreading on immobilized fibrinogen. Platelet adhesion on fibrinogen- and collagen-coated surface under flow was also tested to assess the ability of the platelets to resist hydrodynamic drag forces. Data showed a drastic inhibition of the β3-ΔTNITYRGT platelets to bind soluble fibrinogen and spread on immobilized fibrinogen in contrast to a partially impaired fibrinogen binding and an almost unaffected spreading exhibited in the β3-ΔNITY platelets. Behaviors of the β3-ΔRGT platelets were consistent with the previous observations in the β3-ΔRGT knock-in platelets. The adhesion impairment of platelets with the β3 mutants under flow was in different orders of magnitude shown as: β3-ΔTNITYRGT>β3-ΔRGT>β3-ΔNITY to fibrinogen-coated surface, and β3-ΔTNITYRGT>β3-ΔNITY>β3-ΔRGT to collagen-coated surface. To evaluate the interaction of the β3 mutants with signaling molecules, GST pull-down and immunofluorescent assays were performed. Results showed that β3-ΔRGT interacted with kindlin but not c-Src, β3-ΔNITY interacted with c-Src but not kindlin, while β3-ΔTNITYRGT did not interact with both proteins. This study provided evidence in platelets at both static and flow conditions that the calpain cleavage-related sequences of integrin β3, i.e. T755NITYRGT762, R760GT762, and N756ITY759 participate in bidirectional, outside-in, and inside-out signaling, respectively and the association of c-Src or kindlin with β3 integrin may regulate these processes.
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Affiliation(s)
- Xiaofeng Shi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Jichun Yang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiongying Cui
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jiansong Huang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Department of Hematology, Institute of Hematology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zhangbiao Long
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yulan Zhou
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Ping Liu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Lanlan Tao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zheng Ruan
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Bing Xiao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wei Zhang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Dongya Li
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Kesheng Dai
- Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Key Laboratory of Thrombosis and Hemostasis, Ministry of Health, Suzhou, 215006, China
| | - Jianhua Mao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- * E-mail: (JM); (XX)
| | - Xiaodong Xi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- * E-mail: (JM); (XX)
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35
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Sharma S, Skowronek A, Erdmann KS. The role of the Lowe syndrome protein OCRL in the endocytic pathway. Biol Chem 2016; 396:1293-300. [PMID: 26351914 DOI: 10.1515/hsz-2015-0180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/15/2015] [Indexed: 12/12/2022]
Abstract
Mutations of the inositol-5-phosphatase OCRL cause Lowe syndrome and Dent-II disease. Both are rare genetic disorders characterized by renal defects. Lowe syndrome is furthermore characterized by defects of the eye (congenital cataracts) and nervous system (mental disabilities, hypotonia). OCRL has been localised to various endocytic compartments suggesting impairments in the endocytic pathway as possible disease mechanism. Recent evidence strongly supports this view and shows essential roles of OCRL at clathrin coated pits, transport of cargo from endosomes to the trans-Golgi network as well as recycling of receptors from endosomes to the plasma membrane. In particular in vitro and in vivo evidence demonstrates an important role of OCRL in recycling of megalin, a multi-ligand receptor crucial for reabsorption of nutrients in the proximal tubulus, a process severely impaired in Lowe syndrome patients. Thus defects in the endocytic pathway are likely to significantly contribute to the kidney phenotype in Lowe syndrome and Dent-II disease.
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36
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Autophagosome-lysosome fusion triggers a lysosomal response mediated by TLR9 and controlled by OCRL. Nat Cell Biol 2016; 18:839-850. [PMID: 27398910 PMCID: PMC5040511 DOI: 10.1038/ncb3386] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 06/09/2016] [Indexed: 12/14/2022]
Abstract
Phosphoinositides (PtdIns) control fundamental cell processes, and inherited defects of PtdIns kinases or phosphatases cause severe human diseases, including Lowe syndrome due to mutations in OCRL, which encodes a PtdIns(4,5)P2 5-phosphatase. Here we unveil a lysosomal response to the arrival of autophagosomal cargo in which OCRL plays a key part. We identify mitochondrial DNA and TLR9 as the cargo and the receptor that triggers and mediates, respectively, this response. This lysosome-cargo response is required to sustain the autophagic flux and involves a local increase in PtdIns(4,5)P2 that is confined in space and time by OCRL. Depleting or inhibiting OCRL leads to an accumulation of lysosomal PtdIns(4,5)P2, an inhibitor of the calcium channel mucolipin-1 that controls autophagosome-lysosome fusion. Hence, autophagosomes accumulate in OCRL-depleted cells and in the kidneys of Lowe syndrome patients. Importantly, boosting the activity of mucolipin-1 with selective agonists restores the autophagic flux in cells from Lowe syndrome patients.
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37
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Picas L, Gaits-Iacovoni F, Goud B. The emerging role of phosphoinositide clustering in intracellular trafficking and signal transduction. F1000Res 2016; 5. [PMID: 27092250 PMCID: PMC4821294 DOI: 10.12688/f1000research.7537.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/23/2016] [Indexed: 01/03/2023] Open
Abstract
Phosphoinositides are master regulators of multiple cellular processes: from vesicular trafficking to signaling, cytoskeleton dynamics, and cell growth. They are synthesized by the spatiotemporal regulated activity of phosphoinositide-metabolizing enzymes. The recent observation that some protein modules are able to cluster phosphoinositides suggests that alternative or complementary mechanisms might operate to stabilize the different phosphoinositide pools within cellular compartments. Herein, we discuss the different known and potential molecular players that are prone to engage phosphoinositide clustering and elaborate on how such a mechanism might take part in the regulation of intracellular trafficking and signal transduction.
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Affiliation(s)
- Laura Picas
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, Montpellier, France
| | - Frederique Gaits-Iacovoni
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Bruno Goud
- Institut Curie, PSL Research University, CNRS UMR 144, Paris, France
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38
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Personnic N, Bärlocher K, Finsel I, Hilbi H. Subversion of Retrograde Trafficking by Translocated Pathogen Effectors. Trends Microbiol 2016; 24:450-462. [PMID: 26924068 DOI: 10.1016/j.tim.2016.02.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/22/2016] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
Intracellular bacterial pathogens subvert the endocytic bactericidal pathway to form specific replication-permissive compartments termed pathogen vacuoles or inclusions. To this end, the pathogens employ type III or type IV secretion systems, which translocate dozens, if not hundreds, of different effector proteins into their host cells, where they manipulate vesicle trafficking and signaling pathways in favor of the intruders. While the distinct cocktail of effectors defines the specific processes by which a pathogen vacuole is formed, the different pathogens commonly target certain vesicle trafficking routes, including the endocytic or secretory pathway. Recently, the retrograde transport pathway from endosomal compartments to the trans-Golgi network emerged as an important route affecting pathogen vacuole formation. Here, we review current insight into the host cell's retrograde trafficking pathway and how vacuolar pathogens of the genera Legionella, Coxiella, Salmonella, Chlamydia, and Simkania employ mechanistically distinct strategies to subvert this pathway, thus promoting intracellular survival and replication.
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Affiliation(s)
- Nicolas Personnic
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Kevin Bärlocher
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Ivo Finsel
- Max von Pettenkofer Institute, Ludwig-Maximilians University Munich, Pettenkoferstrasse 9a, 80336 Munich, Germany
| | - Hubert Hilbi
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland; Max von Pettenkofer Institute, Ludwig-Maximilians University Munich, Pettenkoferstrasse 9a, 80336 Munich, Germany.
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39
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Cauvin C, Rosendale M, Gupta-Rossi N, Rocancourt M, Larraufie P, Salomon R, Perrais D, Echard A. Rab35 GTPase Triggers Switch-like Recruitment of the Lowe Syndrome Lipid Phosphatase OCRL on Newborn Endosomes. Curr Biol 2015; 26:120-8. [PMID: 26725203 DOI: 10.1016/j.cub.2015.11.040] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/23/2015] [Accepted: 11/11/2015] [Indexed: 12/17/2022]
Abstract
Phosphoinositide (PtdIns) homeostasis requires a tight spatial and temporal regulation during the endocytic process [1]. Indeed, PtdIns(4,5)P2 plays a crucial role in endocytosis by controlling clathrin-coated pit formation, whereas its conversion into PtdIns4P right after scission of clathrin-coated vesicles (CCVs) is essential for successful uncoating and cargo sorting [1-6]. In non-neuronal cells, endosomal PtdIns(4,5)P2 hydrolysis critically relies on the lipid phosphatase OCRL [7-9], the inactivation of which causes the Oculo-Cerebro-Renal syndrome of Lowe [10, 11]. To understand the coupling between PtdIns(4,5)P2 hydrolysis and endosome formation, a key issue is thus to unravel the mechanism by which OCRL is recruited on CCVs precisely after their scission from the plasma membrane. Here we found that the Rab35 GTPase, which plays a fundamental but poorly understood role in endosomal trafficking after cargo internalization [12-21], directly recruits the OCRL phosphatase immediately after scission of the CCVs. Consistent with Rab35 and OCRL acting together, depletion of either Rab35 or OCRL leads to retention of internalized receptors such as the endogenous cation-independent mannose-6-phosphate receptor (CI-MPR) in peripheral clathrin-positive endosomes that display abnormal association with PtdIns(4,5)P2- and actin-binding proteins. Remarkably, Rab35 loading on CCVs rapidly follows the recruitment of the AP2-binding Rab35 GEF/activator DENND1A (connecdenn 1) and the disappearance of the Rab35 GAP/inhibitor EPI64B. We propose that the precise spatial and temporal activation of Rab35 acts as a major switch for OCRL recruitment on newborn endosomes, post-scission PtdIns(4,5)P2 hydrolysis, and subsequent endosomal trafficking.
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Affiliation(s)
- Clothilde Cauvin
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 Rue du Dr. Roux, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique UMR3691, 75015 Paris, France; Institut de Formation Doctorale, Sorbonne Universités and Université Pierre et Marie Curie, Université Paris 06, 75252 Paris, France
| | - Morgane Rosendale
- University of Bordeaux, 33000 Bordeaux, France; Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Neetu Gupta-Rossi
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 Rue du Dr. Roux, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique UMR3691, 75015 Paris, France
| | - Murielle Rocancourt
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 Rue du Dr. Roux, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique UMR3691, 75015 Paris, France
| | - Pierre Larraufie
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 Rue du Dr. Roux, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique UMR3691, 75015 Paris, France
| | - Rémi Salomon
- Service de Néphrologie Pédiatrique, AP-HP Hôpital Necker, INSERM U983, 75015 Paris, France
| | - David Perrais
- University of Bordeaux, 33000 Bordeaux, France; Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France.
| | - Arnaud Echard
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 Rue du Dr. Roux, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique UMR3691, 75015 Paris, France.
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40
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Campa CC, Martini M, De Santis MC, Hirsch E. How PI3K-derived lipids control cell division. Front Cell Dev Biol 2015; 3:61. [PMID: 26484344 PMCID: PMC4588110 DOI: 10.3389/fcell.2015.00061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/14/2015] [Indexed: 01/18/2023] Open
Abstract
To succeed in cell division, intense cytoskeletal and membrane remodeling are required to allow accurate chromosome segregation and cytoplasm partitioning. Spatial restriction of the actin dynamics and vesicle trafficking define the cell symmetry and equivalent membrane scission events, respectively. Protein complexes coordinating mitosis are recruited to membrane microdomains characterized by the presence of the phosphatidylinositol lipid members (PtdIns), like PtdIns(3,4,5)P3,PtdIns(4,5)P2, and PtdIns(3)P. These PtdIns represent a minor component of cell membranes, defining membrane domain identity, ultimately controlling cytoskeleton and membrane dynamics during mitosis. The coordinated presence of PtdIns(3,4,5)P3 at the cell poles and PtdIns(4,5)P2 at the cleavage furrow controls the polarity of the actin cytoskeleton leading to symmetrical cell division. In the endosomal compartment, the trafficking of PtdIns(3)P positive vesicles allows the recruitment of the protein machinery required for the abscission.
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Affiliation(s)
- Carlo C Campa
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Miriam Martini
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Maria C De Santis
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Emilio Hirsch
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
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41
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Nakatsu F, Messa M, Nández R, Czapla H, Zou Y, Strittmatter SM, De Camilli P. Sac2/INPP5F is an inositol 4-phosphatase that functions in the endocytic pathway. ACTA ACUST UNITED AC 2015; 209:85-95. [PMID: 25869668 PMCID: PMC4395491 DOI: 10.1083/jcb.201409064] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The function of Sac2/INPP5F in the endocytic pathway and its activity as a 4-phosphatase suggest that Sac2/INPP5F and OCRL may cooperate in the sequential dephosphorylation of PI(4,5)P2 in a partnership that mimics that of the two phosphatase modules of synaptojanin. The recruitment of inositol phosphatases to endocytic membranes mediates dephosphorylation of PI(4,5)P2, a phosphoinositide concentrated in the plasma membrane, and prevents its accumulation on endosomes. The importance of the conversion of PI(4,5)P2 to PtdIns during endocytosis is demonstrated by the presence of both a 5-phosphatase and a 4-phosphatase (Sac domain) module in the synaptojanins, endocytic PI(4,5)P2 phosphatases conserved from yeast to humans and the only PI(4,5)P2 phosphatases in yeast. OCRL, another 5-phosphatase that couples endocytosis to PI(4,5)P2 dephosphorylation, lacks a Sac domain. Here we show that Sac2/INPP5F is a PI4P phosphatase that colocalizes with OCRL on endocytic membranes, including vesicles formed by clathrin-mediated endocytosis, macropinosomes, and Rab5 endosomes. An OCRL–Sac2/INPP5F interaction could be demonstrated by coimmunoprecipitation and was potentiated by Rab5, whose activity is required to recruit Sac2/INPP5F to endosomes. Sac2/INPP5F and OCRL may cooperate in the sequential dephosphorylation of PI(4,5)P2 at the 5 and 4 position of inositol in a partnership that mimics that of the two phosphatase modules of synaptojanin.
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Affiliation(s)
- Fubito Nakatsu
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Mirko Messa
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Ramiro Nández
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Heather Czapla
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Yixiao Zou
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Stephen M Strittmatter
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Pietro De Camilli
- Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510 Department of Cell Biology, Howard Hughes Medical Institute, Department of Neurology, and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
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Hsu F, Hu F, Mao Y. Spatiotemporal control of phosphatidylinositol 4-phosphate by Sac2 regulates endocytic recycling. ACTA ACUST UNITED AC 2015; 209:97-110. [PMID: 25869669 PMCID: PMC4395482 DOI: 10.1083/jcb.201408027] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Sac2 (INPP5F) is a phosphoinositide 4-phosphatase that specifically hydrolyzes PI(4)P and regulates endocytic recycling. It is well established that the spatial- and temporal-restricted generation and turnover of phosphoinositides (PIs) by a cascade of PI-metabolizing enzymes is a key regulatory mechanism in the endocytic pathway. Here, we demonstrate that the Sac1 domain–containing protein Sac2 is a PI 4-phosphatase that specifically hydrolyzes phosphatidylinositol 4-phosphate in vitro. We further show that Sac2 colocalizes with early endosomal markers and is recruited to transferrin (Tfn)-containing vesicles during endocytic recycling. Exogenous expression of the catalytically inactive mutant Sac2C458S resulted in altered cellular distribution of Tfn receptors and delayed Tfn recycling. Furthermore, genomic ablation of Sac2 caused a similar perturbation on Tfn and integrin recycling as well as defects in cell migration. Structural characterization of Sac2 revealed a unique pleckstrin-like homology Sac2 domain conserved in all Sac2 orthologues. Collectively, our findings provide evidence for the tight regulation of PIs by Sac2 in the endocytic recycling pathway.
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Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Fenghua Hu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
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43
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Oltrabella F, Pietka G, Ramirez IBR, Mironov A, Starborg T, Drummond IA, Hinchliffe KA, Lowe M. The Lowe syndrome protein OCRL1 is required for endocytosis in the zebrafish pronephric tubule. PLoS Genet 2015; 11:e1005058. [PMID: 25838181 PMCID: PMC4383555 DOI: 10.1371/journal.pgen.1005058] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 02/07/2015] [Indexed: 02/03/2023] Open
Abstract
Lowe syndrome and Dent-2 disease are caused by mutation of the inositol 5-phosphatase OCRL1. Despite our increased understanding of the cellular functions of OCRL1, the underlying basis for the renal tubulopathy seen in both human disorders, of which a hallmark is low molecular weight proteinuria, is currently unknown. Here, we show that deficiency in OCRL1 causes a defect in endocytosis in the zebrafish pronephric tubule, a model for the mammalian renal tubule. This coincides with a reduction in levels of the scavenger receptor megalin and its accumulation in endocytic compartments, consistent with reduced recycling within the endocytic pathway. We also observe reduced numbers of early endocytic compartments and enlarged vacuolar endosomes in the sub-apical region of pronephric cells. Cell polarity within the pronephric tubule is unaffected in mutant embryos. The OCRL1-deficient embryos exhibit a mild ciliogenesis defect, but this cannot account for the observed impairment of endocytosis. Catalytic activity of OCRL1 is required for renal tubular endocytosis and the endocytic defect can be rescued by suppression of PIP5K. These results indicate for the first time that OCRL1 is required for endocytic trafficking in vivo, and strongly support the hypothesis that endocytic defects are responsible for the renal tubulopathy in Lowe syndrome and Dent-2 disease. Moreover, our results reveal PIP5K as a potential therapeutic target for Lowe syndrome and Dent-2 disease. Phosphoinositide lipids are key regulators of cellular physiology and consequently enzymes that generate or remove these lipids are of fundamental importance. Mutation of one such enzyme, called OCRL1, causes two disorders in humans, Lowe syndrome and Dent-2 disease. However, the underlying mechanisms remain poorly defined. Here, we demonstrate that OCRL1 regulates endocytosis, the process by which cells internalize material from their extracellular environment. Importantly, this is demonstrated in a physiologically relevant tissue in vivo, namely the zebrafish renal tubule. Defective endocytosis can explain the renal symptoms seen in Lowe syndrome and Dent-2 patients. We also report that defects in cell polarity or cilia formation cannot explain the renal symptoms. This study not only increases our understanding of the endocytic pathway, it also provides a mechanistic explanation for the renal defects observed in Lowe syndrome and Dent-2 patients.
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Affiliation(s)
| | - Grzegorz Pietka
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Aleksandr Mironov
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Toby Starborg
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Iain A Drummond
- Nephrology Division, Massachusetts General Hospital and Department of Genetics, Harvard Medical School, Charlestown, Massachusetts, United States of America
| | | | - Martin Lowe
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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Madhivanan K, Ramadesikan S, Aguilar RC. Role of Ocrl1 in primary cilia assembly. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:331-47. [PMID: 26008789 DOI: 10.1016/bs.ircmb.2015.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Lowe syndrome is a lethal X-linked genetic disorder characterized by congenital cataracts, mental retardation, and kidney dysfunction. It is caused by mutations in the OCRL1 (oculocerebrorenal syndrome of Lowe) gene that encodes a phosphatidylinositol 5-phosphatase (EC 3.1.3.36). The gene product Ocrl1 has been linked to a multitude of functions due to the central role played by phosphoinositides in signaling. Moreover, this protein also has the ability to bind Rho GTPases, the master regulators of the actin cytoskeleton, and to interact with elements of the vesicle trafficking machinery. It is currently under investigation how deficiencies in Ocrl1 affect these different processes and contribute to patient symptoms. This chapter outlines the known physiological roles of Ocrl1 which might be relevant to the mechanism underlying Lowe syndrome.
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Affiliation(s)
| | - Swetha Ramadesikan
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - R Claudio Aguilar
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
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45
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Waugh MG. PIPs in neurological diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1066-82. [PMID: 25680866 DOI: 10.1016/j.bbalip.2015.02.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/29/2015] [Accepted: 02/01/2015] [Indexed: 12/19/2022]
Abstract
Phosphoinositide (PIP) lipids regulate many aspects of cell function in the nervous system including receptor signalling, secretion, endocytosis, migration and survival. Levels of PIPs such as PI4P, PI(4,5)P2 and PI(3,4,5)P3 are normally tightly regulated by phosphoinositide kinases and phosphatases. Deregulation of these biochemical pathways leads to lipid imbalances, usually on intracellular endosomal membranes, and these changes have been linked to a number of major neurological diseases including Alzheimer's, Parkinson's, epilepsy, stroke, cancer and a range of rarer inherited disorders including brain overgrowth syndromes, Charcot-Marie-Tooth neuropathies and neurodevelopmental conditions such as Lowe's syndrome. This article analyses recent progress in this area and explains how PIP lipids are involved, to varying degrees, in almost every class of neurological disease. This article is part of a Special Issue entitled Brain Lipids.
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Affiliation(s)
- Mark G Waugh
- Lipid and Membrane Biology Group, Institute for Liver and Digestive Health, UCL, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom.
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46
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Mendelian disorders of PI metabolizing enzymes. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:867-81. [PMID: 25510381 DOI: 10.1016/j.bbalip.2014.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/18/2014] [Accepted: 12/01/2014] [Indexed: 12/18/2022]
Abstract
More than twenty different genetic diseases have been described that are caused by mutations in phosphoinositide metabolizing enzymes, mostly in phosphoinositide phosphatases. Although generally ubiquitously expressed, mutations in these enzymes, which are mainly loss-of-function, result in tissue-restricted clinical manifestations through mechanisms that are not completely understood. Here we analyze selected disorders of phosphoinositide metabolism grouped according to the principle tissue affected: the nervous system, muscle, kidney, the osteoskeletal system, the eye, and the immune system. We will highlight what has been learnt so far from the study of these disorders about not only the cellular and molecular pathways that are involved or are governed by phosphoinositides, but also the many gaps that remain to be filled to gain a full understanding of the pathophysiological mechanisms underlying the clinical manifestations of this steadily growing class of diseases, most of which still remain orphan in terms of treatment. This article is part of a Special Issue entitled Phosphoinositides.
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47
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Merrifield CJ, Kaksonen M. Endocytic accessory factors and regulation of clathrin-mediated endocytosis. Cold Spring Harb Perspect Biol 2014; 6:a016733. [PMID: 25280766 DOI: 10.1101/cshperspect.a016733] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Up to 60 different proteins are recruited to the site of clathrin-mediated endocytosis in an ordered sequence. These accessory proteins have roles during all the different stages of clathrin-mediated endocytosis. First, they participate in the initiation of the endocytic event, thereby determining when and where endocytic vesicles are made; later they are involved in the maturation of the clathrin coat, recruitment of specific cargo molecules, bending of the membrane, and finally in scission and uncoating of the nascent vesicle. In addition, many of the accessory components are involved in regulating and coupling the actin cytoskeleton to the endocytic membrane. We will discuss the different accessory components and their various roles. Most of the data comes from studies performed with cultured mammalian cells or yeast cells. The process of endocytosis is well conserved between these different organisms, but there are also many interesting differences that may shed light on the mechanistic principles of endocytosis.
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Affiliation(s)
- Christien J Merrifield
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique UPR3082, 91198 Gif-sur-Yvette, France
| | - Marko Kaksonen
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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48
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Hsu F, Mao Y. The structure of phosphoinositide phosphatases: Insights into substrate specificity and catalysis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:698-710. [PMID: 25264170 DOI: 10.1016/j.bbalip.2014.09.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 12/17/2022]
Abstract
Phosphoinositides (PIs) are a group of key signaling and structural lipid molecules involved in a myriad of cellular processes. PI phosphatases, together with PI kinases, are responsible for the conversion of PIs between distinctive phosphorylation states. PI phosphatases are a large collection of enzymes that are evolved from at least two disparate ancestors. One group is distantly related to endonucleases, which apply divalent metal ions for phosphoryl transfer. The other group is related to protein tyrosine phosphatases, which contain a highly conserved active site motif Cys-X5-Arg (CX5R). In this review, we focus on structural insights to illustrate current understandings of the molecular mechanisms of each PI phosphatase family, with emphasis on their structural basis for substrate specificity determinants and catalytic mechanisms. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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49
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Nández R, Balkin DM, Messa M, Liang L, Paradise S, Czapla H, Hein MY, Duncan JS, Mann M, De Camilli P. A role of OCRL in clathrin-coated pit dynamics and uncoating revealed by studies of Lowe syndrome cells. eLife 2014; 3:e02975. [PMID: 25107275 PMCID: PMC4358339 DOI: 10.7554/elife.02975] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 08/07/2014] [Indexed: 12/15/2022] Open
Abstract
Mutations in the inositol 5-phosphatase OCRL cause Lowe syndrome and Dent's disease. Although OCRL, a direct clathrin interactor, is recruited to late-stage clathrin-coated pits, clinical manifestations have been primarily attributed to intracellular sorting defects. Here we show that OCRL loss in Lowe syndrome patient fibroblasts impacts clathrin-mediated endocytosis and results in an endocytic defect. These cells exhibit an accumulation of clathrin-coated vesicles and an increase in U-shaped clathrin-coated pits, which may result from sequestration of coat components on uncoated vesicles. Endocytic vesicles that fail to lose their coat nucleate the majority of the numerous actin comets present in patient cells. SNX9, an adaptor that couples late-stage endocytic coated pits to actin polymerization and which we found to bind OCRL directly, remains associated with such vesicles. These results indicate that OCRL acts as an uncoating factor and that defects in clathrin-mediated endocytosis likely contribute to pathology in patients with OCRL mutations. DOI:http://dx.doi.org/10.7554/eLife.02975.001 Oculo-Cerebro-Renal syndrome of Lowe (Lowe syndrome) is a rare genetic disorder that can cause cataracts, mental disabilities and kidney dysfunction. It is caused by mutations in the gene encoding OCRL, a protein that modifies a membrane lipid and that is found on membranes transporting molecules (cargo) into cells by a process known as endocytosis. During endocytosis, the cell outer membrane is deformed into a pit that engulfs the cargo to be taken up by the cell. The pit then pinches off from the outer membrane to form a vesicle—a bubble-like compartment—inside the cell that transports the cargo to its destination. In one type of endocytosis, this process is mediated by a basket-like coat primarily made up from the protein clathrin that assembles at the membrane patch to be internalized. After the vesicle is released from the cell membrane, the clathrin coat is broken apart and its components are shed and recycled for use by new budding endocytic vesicles. The OCRL protein had previously been observed associated to newly forming clathrin-coated vesicles, but the significance of this was not known. Now, Nández et al. have used a range of imaging and analytical techniques to further investigate the properties of OCRL, taking advantage of cells from patients with Lowe syndrome. These cells lack OCRL, and so allow the effect of OCRL's absence on cell function to be deduced. OCRL destroys the membrane lipid that helps to connect the clathrin coat to the membrane, and Nández et al. show that without OCRL the newly formed vesicle moves into the cell but fails to efficiently shed its clathrin coat. Thus, a large fraction of clathrin coat components remain trapped on the vesicles, reducing the amount of such components available to help new pits develop into vesicles. As a consequence, the cell has difficulty internalizing molecules. Collectively, the findings of Nández et al. outline that OCRL plays a role in the regulation of endocytosis in addition to its previously reported actions in the control of intracellular membrane traffic. The results also help to explain some of the symptoms seen in Lowe syndrome patients. DOI:http://dx.doi.org/10.7554/eLife.02975.002
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Affiliation(s)
- Ramiro Nández
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Daniel M Balkin
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Mirko Messa
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Liang Liang
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, United States
| | - Summer Paradise
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Heather Czapla
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Marco Y Hein
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - James S Duncan
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, United States
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Pietro De Camilli
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
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50
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Croisé P, Estay-Ahumada C, Gasman S, Ory S. Rho GTPases, phosphoinositides, and actin: a tripartite framework for efficient vesicular trafficking. Small GTPases 2014; 5:e29469. [PMID: 24914539 DOI: 10.4161/sgtp.29469] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rho GTPases are well known regulators of the actin cytoskeleton that act by binding and activating actin nucleators. They are therefore involved in many actin-based processes, including cell migration, cell polarity, and membrane trafficking. With the identification of phosphoinositide kinases and phosphatases as potential binding partners or effectors, Rho GTPases also appear to participate in the regulation of phosphoinositide metabolism. Since both actin dynamics and phosphoinositide turnover affect the efficiency and the fidelity of vesicle transport between cell compartments, Rho GTPases have emerged as critical players in membrane trafficking. Rho GTPase activity, actin remodeling, and phosphoinositide metabolism need to be coordinated in both space and time to ensure the progression of vesicles along membrane trafficking pathways. Although most molecular pathways are still unclear, in this review, we will highlight recent advances made in our understanding of how Rho-dependent signaling pathways organize actin dynamics and phosphoinositides and how phosphoinositides potentially provide negative feedback to Rho GTPases during endocytosis, exocytosis and membrane exchange between intracellular compartments.
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Affiliation(s)
- Pauline Croisé
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Catherine Estay-Ahumada
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Gasman
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Ory
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
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