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Zhao X, Quintremil S, Rodriguez Castro ED, Cui H, Moraga D, Wang T, Vallee RB, Solmaz SR. Molecular mechanism for recognition of the cargo adapter Rab6 GTP by the dynein adapter BicD2. Life Sci Alliance 2024; 7:e202302430. [PMID: 38719748 PMCID: PMC11077774 DOI: 10.26508/lsa.202302430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/12/2024] Open
Abstract
Rab6 is a key modulator of protein secretion. The dynein adapter Bicaudal D2 (BicD2) recruits the motors cytoplasmic dynein and kinesin-1 to Rab6GTP-positive vesicles for transport; however, it is unknown how BicD2 recognizes Rab6. Here, we establish a structural model for recognition of Rab6GTP by BicD2, using structure prediction and mutagenesis. The binding site of BicD2 spans two regions of Rab6 that undergo structural changes upon the transition from the GDP- to GTP-bound state, and several hydrophobic interface residues are rearranged, explaining the increased affinity of the active GTP-bound state. Mutations of Rab6GTP that abolish binding to BicD2 also result in reduced co-migration of Rab6GTP/BicD2 in cells, validating our model. These mutations also severely diminished the motility of Rab6-positive vesicles in cells, highlighting the importance of the Rab6GTP/BicD2 interaction for overall motility of the multi-motor complex that contains both kinesin-1 and dynein. Our results provide insights into trafficking of secretory and Golgi-derived vesicles and will help devise therapies for diseases caused by BicD2 mutations, which selectively affect the affinity to Rab6 and other cargoes.
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Affiliation(s)
- Xiaoxin Zhao
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Sebastian Quintremil
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | | | - Heying Cui
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - David Moraga
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Tingyao Wang
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Richard B Vallee
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sozanne R Solmaz
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
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2
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Zhang W, Tariq M, Roy B, Shen J, Khan A, Altaf Malik N, He S, Baig SM, Fang X, Zhang J. Whole exome sequencing identified a homozygous novel variant in DOP1A gene in the Pakistan family with neurodevelopmental disabilities: case report and literature review. Front Genet 2024; 15:1351710. [PMID: 38818041 PMCID: PMC11137318 DOI: 10.3389/fgene.2024.1351710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 04/11/2024] [Indexed: 06/01/2024] Open
Abstract
Background Hereditary neurodevelopmental disorders (NDDs) are prevalent in poorly prognostic pediatric diseases, but the pathogenesis of NDDs is still unclear. Irregular myelination could be one of the possible causes of NDDs. Case presentation Here, whole exome sequencing was carried out for a consanguineous Pakistani family with NDDs to identify disease-associated variants. The co-segregation of candidate variants in the family was validated using Sanger sequencing. The potential impact of the gene on NDDs has been supported by conservation analysis, protein prediction, and expression analysis. A novel homozygous variant DOP1A(NM_001385863.1):c.2561A>G was identified. It was concluded that the missense variant might affect the protein-protein binding sites of the critical MEC interaction region of DOP1A, and DOP1A-MON2 may cause stability deficits in Golgi-endosome protein traffic. Proteolipid protein (PLP) and myelin-associate glycoprotein (MAG) could be targets of the DOP1A-MON2 Golgi-endosome traffic complex, especially during the fetal stage and the early developmental stages. This further supports the perspective that disorganized myelinogenesis due to congenital DOP1A deficiency might cause neurodevelopmental disorders (NDDs). Conclusion Our case study revealed the potential pathway of myelinogenesis-relevant NDDs and identified DOP1A as a potential NDDs-relevant gene in humans.
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Affiliation(s)
- Wei Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- BGI Genomics, Shenzhen, China
| | - Muhammad Tariq
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C PIEAS), Faisalabad, Pakistan
| | - Bhaskar Roy
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Juan Shen
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Ayaz Khan
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C PIEAS), Faisalabad, Pakistan
| | - Naveed Altaf Malik
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C PIEAS), Faisalabad, Pakistan
| | - Sijie He
- Hebei Industrial Technology Research Institute of Genomics in Maternal and Child Health, Shijiazhuang, China
- Clin Lab, BGI Genomics, Shijiazhuang, China
| | - Shahid Mahmood Baig
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C PIEAS), Faisalabad, Pakistan
| | - Xiaodong Fang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Jianguo Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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Park S, Noblett N, Pitts L, Colavita A, Wehman AM, Jin Y, Chisholm AD. Dopey-dependent regulation of extracellular vesicles maintains neuronal morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.591898. [PMID: 38766017 PMCID: PMC11100700 DOI: 10.1101/2024.05.07.591898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Mature neurons maintain their distinctive morphology for extended periods in adult life. Compared to developmental neurite outgrowth, axon guidance, and target selection, relatively little is known of mechanisms that maintain mature neuron morphology. Loss of function in C. elegans DIP-2, a member of the conserved lipid metabolic regulator Dip2 family, results in progressive overgrowth of neurites in adults. We find that dip-2 mutants display specific genetic interactions with sax-2, the C. elegans ortholog of Drosophila Furry and mammalian FRY. Combined loss of DIP-2 and SAX-2 results in severe disruption of neuronal morphology maintenance accompanied by increased release of neuronal extracellular vesicles (EVs). By screening for suppressors of dip-2 sax-2 double mutant defects we identified gain-of-function (gf) mutations in the conserved Dopey family protein PAD-1 and its associated phospholipid flippase TAT-5/ATP9A. In dip-2 sax-2 double mutants carrying either pad-1(gf) or tat-5(gf) mutation, EV release is reduced and neuronal morphology across multiple neuron types is restored to largely normal. PAD-1(gf) acts cell autonomously in neurons. The domain containing pad-1(gf) is essential for PAD-1 function, and PAD-1(gf) protein displays increased association with the plasma membrane and inhibits EV release. Our findings uncover a novel functional network of DIP-2, SAX-2, PAD-1, and TAT-5 that maintains morphology of neurons and other types of cells, shedding light on the mechanistic basis of neurological disorders involving human orthologs of these genes.
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Affiliation(s)
- Seungmee Park
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Nathaniel Noblett
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Lauren Pitts
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Antonio Colavita
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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4
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Ying R, Li C, Li H, Zou J, Hu M, Hong Q, Shen Y, Hou L, Cheng H, Zhou R. RPGR is a guanine nucleotide exchange factor for the small GTPase RAB37 required for retinal function via autophagy regulation. Cell Rep 2024; 43:114010. [PMID: 38536817 DOI: 10.1016/j.celrep.2024.114010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/28/2024] [Accepted: 03/13/2024] [Indexed: 04/28/2024] Open
Abstract
Although the small GTPase RAB37 acts as an organizer of autophagosome biogenesis, the upstream regulatory mechanism of autophagy via guanosine diphosphate (GDP)-guanosine triphosphate (GTP) exchange in maintaining retinal function has not been determined. We found that retinitis pigmentosa GTPase regulator (RPGR) is a guanine nucleotide exchange factor that activates RAB37 by accelerating GDP-to-GTP exchange. RPGR directly interacts with RAB37 via the RPGR-RCC1-like domain to promote autophagy through stimulating exchange. Rpgr knockout (KO) in mice leads to photoreceptor degeneration owing to autophagy impairment in the retina. Notably, the retinopathy phenotypes of Rpgr KO retinas are rescued by the adeno-associated virus-mediated transfer of pre-trans-splicing molecules, which produce normal Rpgr mRNAs via trans-splicing in the Rpgr KO retinas. This rescue upregulates autophagy through the re-expression of RPGR in KO retinas to accelerate GDP-to-GTP exchange; thus, retinal homeostasis reverts to normal. Taken together, these findings provide an important missing link for coordinating RAB37 GDP-GTP exchange via the RPGR and retinal homeostasis by autophagy regulation.
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Affiliation(s)
- Ruhong Ying
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Cong Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Huirong Li
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou 325003, China
| | - Juan Zou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Mengxin Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Qiang Hong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Yin Shen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Ling Hou
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou 325003, China.
| | - Hanhua Cheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China.
| | - Rongjia Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China.
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5
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Tan WS, Rong E, Dry I, Lillico S, Law A, Digard P, Whitelaw B, Dalziel RG. Validation of Candidate Host Cell Entry Factors for Bovine Herpes Virus Type-1 Based on a Genome-Wide CRISPR Knockout Screen. Viruses 2024; 16:297. [PMID: 38400072 PMCID: PMC10893506 DOI: 10.3390/v16020297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
To identify host factors that affect Bovine Herpes Virus Type 1 (BoHV-1) infection we previously applied a genome wide CRISPR knockout screen targeting all bovine protein coding genes. By doing so we compiled a list of both pro-viral and anti-viral proteins involved in BoHV-1 replication. Here we provide further analysis of those that are potentially involved in viral entry into the host cell. We first generated single cell knockout clones deficient in some of the candidate genes for validation. We provide evidence that Polio Virus Receptor-related protein (PVRL2) serves as a receptor for BoHV-1, mediating more efficient entry than the previously identified Polio Virus Receptor (PVR). By knocking out two enzymes that catalyze HSPG chain elongation, HST2ST1 and GLCE, we further demonstrate the significance of HSPG in BoHV-1 entry. Another intriguing cluster of candidate genes, COG1, COG2 and COG4-7 encode six subunits of the Conserved Oligomeric Golgi (COG) complex. MDBK cells lacking COG6 produced fewer but bigger plaques compared to control cells, suggesting more efficient release of newly produced virions from these COG6 knockout cells, due to impaired HSPG biosynthesis. We further observed that viruses produced by the COG6 knockout cells consist of protein(s) with reduced N-glycosylation, potentially explaining their lower infectivity. To facilitate candidate validation, we also detailed a one-step multiplex CRISPR interference (CRISPRi) system, an orthogonal method to KO that enables quick and simultaneous deployment of three CRISPRs for efficient gene inactivation. Using CRISPR3i, we verified eight candidates that have been implicated in the synthesis of surface heparan sulfate proteoglycans (HSPGs). In summary, our experiments confirmed the two receptors PVR and PVRL2 for BoHV-1 entry into the host cell and other factors that affect this process, likely through the direct or indirect roles they play during HSPG synthesis and glycosylation of viral proteins.
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Affiliation(s)
- Wenfang Spring Tan
- Division of Infection and Immunity, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK (I.D.); (P.D.); (R.G.D.)
| | - Enguang Rong
- Division of Infection and Immunity, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK (I.D.); (P.D.); (R.G.D.)
| | - Inga Dry
- Division of Infection and Immunity, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK (I.D.); (P.D.); (R.G.D.)
| | - Simon Lillico
- Division of Functional Genetics and Development, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK; (S.L.); (B.W.)
- Centre for Tropical Livestock Genetics and Health, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK
| | - Andy Law
- Division of Genetics and Genomics, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK;
| | - Paul Digard
- Division of Infection and Immunity, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK (I.D.); (P.D.); (R.G.D.)
| | - Bruce Whitelaw
- Division of Functional Genetics and Development, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK; (S.L.); (B.W.)
- Division of Genetics and Genomics, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK;
| | - Robert G. Dalziel
- Division of Infection and Immunity, the Roslin Institute, Easter Bush Campus, University of Edinburgh, Edinburgh EH259RG, UK (I.D.); (P.D.); (R.G.D.)
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6
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Cheng CY, Romero DP, Zoltner M, Yao MC, Turkewitz AP. Structure and dynamics of the contractile vacuole complex in Tetrahymena thermophila. J Cell Sci 2023; 136:jcs261511. [PMID: 37902010 PMCID: PMC10729820 DOI: 10.1242/jcs.261511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/23/2023] [Indexed: 10/31/2023] Open
Abstract
The contractile vacuole complex (CVC) is a dynamic and morphologically complex membrane organelle, comprising a large vesicle (bladder) linked with a tubular reticulum (spongiome). CVCs provide key osmoregulatory roles across diverse eukaryotic lineages, but probing the mechanisms underlying their structure and function is hampered by the limited tools available for in vivo analysis. In the experimentally tractable ciliate Tetrahymena thermophila, we describe four proteins that, as endogenously tagged constructs, localize specifically to distinct CVC zones. The DOPEY homolog Dop1p and the CORVET subunit Vps8Dp localize both to the bladder and spongiome but with different local distributions that are sensitive to osmotic perturbation, whereas the lipid scramblase Scr7p colocalizes with Vps8Dp. The H+-ATPase subunit Vma4 is spongiome specific. The live imaging permitted by these probes revealed dynamics at multiple scales including rapid exchange of CVC-localized and soluble protein pools versus lateral diffusion in the spongiome, spongiome extension and branching, and CVC formation during mitosis. Although the association with DOP1 and VPS8D implicate the CVC in endosomal trafficking, both the bladder and spongiome might be isolated from bulk endocytic input.
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Affiliation(s)
- Chao-Yin Cheng
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Daniel P. Romero
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Martin Zoltner
- Biotechnology Biomedicine Centre of the Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Meng-Chao Yao
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Aaron P. Turkewitz
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
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7
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Mahajan D, Madugula V, Lu L. Rab8 and TNPO1 are ciliary transport adaptors for GTPase Arl13b by interacting with its RVEP motif-containing ciliary targeting sequence. J Biol Chem 2023; 299:104604. [PMID: 36907439 PMCID: PMC10124946 DOI: 10.1016/j.jbc.2023.104604] [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: 08/24/2022] [Revised: 03/04/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
Arl13b, an ARF/Arl-family GTPase, is highly enriched in the cilium. Recent studies have established Arl13b as one of the most crucial regulators for ciliary organization, trafficking, and signaling. The ciliary localization of Arl13b is known to require the RVEP motif. However, its cognitive ciliary transport adaptor has been elusive. Here, by imaging the ciliary localization of truncation and point mutations, we defined the ciliary targeting sequence (CTS) of Arl13b as a C-terminal stretch of 17 amino acids containing the RVEP motif. We found Rab8-GDP, but not Rab8-GTP, and TNPO1 simultaneously and directly bind to the CTS of Arl13b in pull-down assays using cell lysates or purified recombinant proteins. Furthermore, Rab8-GDP substantially enhances the interaction between TNPO1 and CTS. Additionally, we determined that the RVEP motif is an essential element as its mutation abolishes the interaction of the CTS with Rab8-GDP and TNPO1 in pull-down and TurboID-based proximity ligation assays. Finally, knockdown of endogenous Rab8 or TNPO1 decreases the ciliary localization of endogenous Arl13b. Therefore, our results suggest Rab8 and TNPO1 might function together as a ciliary transport adaptor for Arl13b by interacting with its RVEP-containing CTS.
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Affiliation(s)
- Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Viswanadh Madugula
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore.
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8
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Pitts LR, Nguyen AT, Wehman AM. Conserved N- and C-terminal motifs of PAD-1 are required to inhibit extracellular vesicle release. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000625. [PMID: 36188098 PMCID: PMC9520342 DOI: 10.17912/micropub.biology.000625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/11/2022] [Accepted: 08/31/2022] [Indexed: 11/06/2022]
Abstract
Cells release extracellular vesicles (EVs) carrying cargos that can influence development and disease, but the mechanisms that govern EV release by plasma membrane budding are poorly understood. We previously showed that the Dopey protein PAD-1 inhibits EV release from the plasma membrane in C. elegans . However, PAD-1 is large, and the domains required to regulate EV release were unknown. Here, we reveal that the conserved N-terminal EWAD motif and C-terminal leucine zippers are required to inhibit EV release from the plasma membrane. Revealing a role for these domains is an important first step to identifying how EV release is regulated.
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Affiliation(s)
- Lauren R Pitts
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Alexander T Nguyen
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO, USA
,
Correspondence to: Ann M Wehman (
)
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9
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Villari G, Gioelli N, Valdembri D, Serini G. Vesicle choreographies keep up cell-to-extracellular matrix adhesion dynamics in polarized epithelial and endothelial cells. Matrix Biol 2022; 112:62-71. [PMID: 35961423 DOI: 10.1016/j.matbio.2022.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/21/2022] [Accepted: 08/08/2022] [Indexed: 12/19/2022]
Abstract
In metazoans, cell adhesion to the extracellular matrix (ECM) drives the development, functioning, and repair of different tissues, organs, and systems. Disruption or dysregulation of cell-to-ECM adhesion promote the initiation and progression of several diseases, such as bleeding, immune disorders and cancer. Integrins are major ECM transmembrane receptors, whose function depends on both allosteric changes and exo-endocytic traffic, which carries them to and from the plasma membrane. In apico-basally polarized cells, asymmetric adhesion to the ECM is maintained by continuous targeting of the plasma membrane by vesicles coming from the trans Golgi network and carrying ECM proteins. Active integrin-bound ECM is indeed endocytosed and replaced by the exocytosis of fresh ECM. Such vesicular traffic is finely driven by the teamwork of microtubules (MTs) and their associated kinesin and dynein motors. Here, we review the main cytoskeletal actors involved in the control of the spatiotemporal distribution of active integrins and their ECM ligands, highlighting the key role of the synchronous (ant)agonistic cooperation between MT motors transporting vesicular cargoes, in the same or in opposite direction, in the regulation of traffic logistics, and the establishment of epithelial and endothelial cell polarity.
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Affiliation(s)
- Giulia Villari
- Candiolo Cancer Institute - Fondazione del Piemonte per l'Oncologia (FPO) Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 10060, Candiolo, Torino, Italy; Department of Oncology, University of Torino School of Medicine, 10060, Candiolo, Torino, Italy
| | - Noemi Gioelli
- Candiolo Cancer Institute - Fondazione del Piemonte per l'Oncologia (FPO) Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 10060, Candiolo, Torino, Italy; Department of Oncology, University of Torino School of Medicine, 10060, Candiolo, Torino, Italy
| | - Donatella Valdembri
- Candiolo Cancer Institute - Fondazione del Piemonte per l'Oncologia (FPO) Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 10060, Candiolo, Torino, Italy; Department of Oncology, University of Torino School of Medicine, 10060, Candiolo, Torino, Italy.
| | - Guido Serini
- Candiolo Cancer Institute - Fondazione del Piemonte per l'Oncologia (FPO) Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 10060, Candiolo, Torino, Italy; Department of Oncology, University of Torino School of Medicine, 10060, Candiolo, Torino, Italy.
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10
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Zhao P, Han H, Wu X, Wu J, Ren Z. ARP2/3 Regulates Fatty Acid Synthesis by Modulating Lipid Droplets' Motility. Int J Mol Sci 2022; 23:ijms23158730. [PMID: 35955862 PMCID: PMC9368945 DOI: 10.3390/ijms23158730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/01/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
The breakdown of lipid droplets (LDs) provides energy and contributes to the proliferation and migration of cancer cells. Recent studies have suggested that motility plays a key role in LD breakdown. However, the molecular mechanisms underlying LD motility were poorly characterized. In this study, we examined the function of microfilament-associated proteins 2 and 3 (ARP2 and ARP3) in regulating LDs’ motility in Hela cells. ARP2/3 mediated the LDs’ physical contact with F-actin and promoted the recruitment of Myosin Heavy Chain 9 (MYH9). MYH9 regulated the LD content by binding with LDs and ARP2/3. The number of LDs and TG content was increased after MYH9 interfered. The genes related to FA-related genes and neutral lipid synthesis-related genes were significantly increased (p < 0.05) when ARP2 and ARP3 were overexpressed. Bioinformatic analysis indicated that the high expression of ARP2/3 was associated with a poorer prognosis in cervical squamous cell carcinoma (CSCC). This study showed the effect of cytoskeletal filaments on LD metabolism in cancer cells.
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Affiliation(s)
- Pengxiang Zhao
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hongbo Han
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiang Wu
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jian Wu
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhuqing Ren
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
- Correspondence:
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11
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Shi M, Tie HC, Divyanshu M, Sun X, Zhou Y, Boh BK, Vardy LA, Lu L. Arl15 upregulates the TGFβ family signaling by promoting the assembly of the Smad-complex. eLife 2022; 11:76146. [PMID: 35834310 PMCID: PMC9352346 DOI: 10.7554/elife.76146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
The hallmark event of the canonical transforming growth factor β (TGFβ) family signaling is the assembly of the Smad-complex, consisting of the common Smad, Smad4, and phosphorylated receptor-regulated Smads. How the Smad-complex is assembled and regulated is still unclear. Here, we report that active Arl15, an Arf-like small G protein, specifically binds to the MH2 domain of Smad4 and colocalizes with Smad4 at the endolysosome. The binding relieves the autoinhibition of Smad4, which is imposed by the intramolecular interaction between its MH1 and MH2 domains. Activated Smad4 subsequently interacts with phosphorylated receptor-regulated Smads, forming the Smad-complex. Our observations suggest that Smad4 functions as an effector and a GTPase activating protein (GAP) of Arl15. Assembly of the Smad-complex enhances the GAP activity of Smad4 toward Arl15, therefore dissociating Arl15 before the nuclear translocation of the Smad-complex. Our data further demonstrate that Arl15 positively regulates the TGFβ family signaling.
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Affiliation(s)
- Meng Shi
- Skin Research Laboratory, A*STAR, Singapore, singapore, Singapore
| | - Hieng Chiong Tie
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Mahajan Divyanshu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xiuping Sun
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yan Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Boon Kim Boh
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Leah A Vardy
- Skin Research Laboratory, A*STAR, Singapore, singapore, Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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12
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Molière A, Beer KB, Wehman AM. Dopey proteins are essential but overlooked regulators of membrane trafficking. J Cell Sci 2022; 135:274973. [PMID: 35388894 DOI: 10.1242/jcs.259628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Dopey family proteins play crucial roles in diverse processes from morphogenesis to neural function and are conserved from yeast to mammals. Understanding the mechanisms behind these critical functions could have major clinical significance, as dysregulation of Dopey proteins has been linked to the cognitive defects in Down syndrome, as well as neurological diseases. Dopey proteins form a complex with the non-essential GEF-like protein Mon2 and an essential lipid flippase from the P4-ATPase family. Different combinations of Dopey, Mon2 and flippases have been linked to regulating membrane remodeling, from endosomal recycling to extracellular vesicle formation, through their interactions with lipids and other membrane trafficking regulators, such as ARL1, SNX3 and the kinesin-1 light chain KLC2. Despite these important functions and their likely clinical significance, Dopey proteins remain understudied and their roles elusive. Here, we review the major scientific discoveries relating to Dopey proteins and detail key open questions regarding their function to draw attention to these fascinating enigmas.
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Affiliation(s)
- Adrian Molière
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Katharina B Beer
- Rudolf Virchow Center, Julius Maximilian University of Würzburg, D-97080, Würzburg, Germany
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA.,Rudolf Virchow Center, Julius Maximilian University of Würzburg, D-97080, Würzburg, Germany
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13
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Abstract
Phosphoinositides are signalling lipids derived from phosphatidylinositol, a ubiquitous phospholipid in the cytoplasmic leaflet of eukaryotic membranes. Initially discovered for their roles in cell signalling, phosphoinositides are now widely recognized as key integrators of membrane dynamics that broadly impact on all aspects of cell physiology and on disease. The past decade has witnessed a vast expansion of our knowledge of phosphoinositide biology. On the endocytic and exocytic routes, phosphoinositides direct the inward and outward flow of membrane as vesicular traffic is coupled to the conversion of phosphoinositides. Moreover, recent findings on the roles of phosphoinositides in autophagy and the endolysosomal system challenge our view of lysosome biology. The non-vesicular exchange of lipids, ions and metabolites at membrane contact sites in between organelles has also been found to depend on phosphoinositides. Here we review our current understanding of how phosphoinositides shape and direct membrane dynamics to impact on cell physiology, and provide an overview of emerging concepts in phosphoinositide regulation.
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14
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Sun X, Mahajan D, Chen B, Song Z, Lu L. A quantitative study of the Golgi retention of glycosyltransferases. J Cell Sci 2021; 134:272560. [PMID: 34533190 DOI: 10.1242/jcs.258564] [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: 02/16/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022] Open
Abstract
How Golgi glycosyltransferases and glycosidases (hereafter glycosyltransferases) localize to the Golgi is still unclear. Here, we first investigated the post-Golgi trafficking of glycosyltransferases. We found that glycosyltransferases can escape the Golgi to the plasma membrane, where they are subsequently endocytosed to the endolysosome. Post-Golgi glycosyltransferases are probably degraded by ectodomain shedding. We discovered that most glycosyltransferases are not retrieved from post-Golgi sites, indicating that retention rather than retrieval is the primary mechanism for their Golgi localization. We therefore used the Golgi residence time to study Golgi retention of glycosyltransferases quantitatively and systematically. Quantitative analysis of chimeras of ST6GAL1 and either transferrin receptor or tumor necrosis factor α revealed the contributions of three regions of ST6GAL1, namely the N-terminal cytosolic tail, the transmembrane domain and the ectodomain, to Golgi retention. We found that each of the three regions is sufficient for Golgi retention in an additive manner. N-terminal cytosolic tail length negatively affects the Golgi retention of ST6GAL1, similar to effects observed for the transmembrane domain. Therefore, the long N-terminal cytosolic tail and transmembrane domain could act as Golgi export signals for transmembrane secretory cargos. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Xiuping Sun
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore637551
| | - Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore637551
| | - Bing Chen
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore637551
| | - Zhiwei Song
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore138668
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore637551
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15
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Nie ZW, Niu YJ, Zhou W, Zhou DJ, Kim JY, Cui XS. AGS3-dependent trans-Golgi network membrane trafficking is essential for compaction in mouse embryos. J Cell Sci 2020; 133:jcs.243238. [PMID: 33148610 DOI: 10.1242/jcs.243238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 10/26/2020] [Indexed: 11/20/2022] Open
Abstract
Activator of G-protein signaling 3 (AGS3, also known as GPSM1) regulates the trans-Golgi network. The AGS3 GoLoco motif binds to Gαi and thereby regulates the transport of proteins to the plasma membrane. Compaction of early embryos is based on the accumulation of E-cadherin (Cdh1) at cell-contacted membranes. However, how AGS3 regulates the transport of Cdh1 to the plasma membrane remains undetermined. To investigate this, AGS3 was knocked out using the Cas9-sgRNA system. Both trans-Golgi network protein 46 (TGN46, also known as TGOLN2) and transmembrane p24-trafficking protein 7 (TMED7) were tracked in early mouse embryos by tagging these proteins with a fluorescent protein label. We observed that the majority of the AGS3-edited embryos were developmentally arrested and were fragmented after the four-cell stage, exhibiting decreased accumulation of Cdh1 at the membrane. The trans-Golgi network and TMED7-positive vesicles were also dispersed and were not polarized near the membrane. Additionally, increased Gαi1 (encoded by GNAI1) expression could rescue AGS3-overexpressed embryos. In conclusion, AGS3 reinforces the dynamics of the trans-Golgi network and the transport of TMED7-positive cargo containing Cdh1 to the cell-contact surface during early mouse embryo development.
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Affiliation(s)
- Zheng-Wen Nie
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
| | - Ying-Jie Niu
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
| | - Wenjun Zhou
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
| | - Dong-Jie Zhou
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
| | - Ju-Yeon Kim
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
| | - Xiang-Shun Cui
- Department of Animal Sciences, Chungbuk National University, Chungbuk, Cheongju 361-763, Republic of Korea
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16
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Serra-Marques A, Martin M, Katrukha EA, Grigoriev I, Peeters CAE, Liu Q, Hooikaas PJ, Yao Y, Solianova V, Smal I, Pedersen LB, Meijering E, Kapitein LC, Akhmanova A. Concerted action of kinesins KIF5B and KIF13B promotes efficient secretory vesicle transport to microtubule plus ends. eLife 2020; 9:e61302. [PMID: 33174839 PMCID: PMC7710357 DOI: 10.7554/elife.61302] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/10/2020] [Indexed: 01/30/2023] Open
Abstract
Intracellular transport relies on multiple kinesins, but it is poorly understood which kinesins are present on particular cargos, what their contributions are and whether they act simultaneously on the same cargo. Here, we show that Rab6-positive secretory vesicles are transported from the Golgi apparatus to the cell periphery by kinesin-1 KIF5B and kinesin-3 KIF13B, which determine the location of secretion events. KIF5B plays a dominant role, whereas KIF13B helps Rab6 vesicles to reach freshly polymerized microtubule ends, to which KIF5B binds poorly, likely because its cofactors, MAP7-family proteins, are slow in populating these ends. Sub-pixel localization demonstrated that during microtubule plus-end directed transport, both kinesins localize to the vesicle front and can be engaged on the same vesicle. When vesicles reverse direction, KIF13B relocates to the middle of the vesicle, while KIF5B shifts to the back, suggesting that KIF5B but not KIF13B undergoes a tug-of-war with a minus-end directed motor.
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Affiliation(s)
- Andrea Serra-Marques
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Maud Martin
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Eugene A Katrukha
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Ilya Grigoriev
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Cathelijn AE Peeters
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Qingyang Liu
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Peter Jan Hooikaas
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Yao Yao
- Departments of Medical Informatics and Radiology, Biomedical Imaging Group Rotterdam, Erasmus University Medical CenterRotterdamNetherlands
| | - Veronika Solianova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Ihor Smal
- Departments of Medical Informatics and Radiology, Biomedical Imaging Group Rotterdam, Erasmus University Medical CenterRotterdamNetherlands
| | - Lotte B Pedersen
- Department of Biology, Section of Cell Biology and Physiology, the August Krogh Building, University of CopenhagenCopenhagenDenmark
| | - Erik Meijering
- Departments of Medical Informatics and Radiology, Biomedical Imaging Group Rotterdam, Erasmus University Medical CenterRotterdamNetherlands
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht UniversityUtrechtNetherlands
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17
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Mohan S, Mok S, Judge T. Identification of Novel Therapeutic Molecular Targets in Inflammatory Bowel Disease by Using Genetic Databases. Clin Exp Gastroenterol 2020; 13:467-473. [PMID: 33116744 PMCID: PMC7585167 DOI: 10.2147/ceg.s264812] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose Utilization of genetic databases to identify genes involved in ulcerative colitis (UC), Crohn’s disease (CD), and their extra-intestinal manifestations. Methods Protein coding genes involved in ulcerative colitis (3783 genes), Crohn’s disease (3980 genes), uveitis (1043 genes), arthritis (5583 genes), primary sclerosing cholangitis (PSC) (1313 genes), and pyoderma gangrenosum (119 genes) were categorized using four genetic databases. These include Genecards: The Human Gene Database (www.genecards.org), DisGeNET (https://www.disgenet.org/), The Comparative Toxicogenomics Database (http://ctdbase.org/) and the Universal Protein Resource (https://www.uniprot.org/). NDex, Network Data Exchange (http://www.ndexbio.org/), was then utilized for mapping a unique signal pathway from the identified shared genes involved in the above disease processes. Results We have detected a unique array of 20 genes with the highest probability of overlay in UC, CD, uveitis, arthritis, pyoderma gangrenosum, and PSC. Figure 1 represents the interactome of these 20 protein coding genes. Of note, unique immune modulators in different disease processes are also noted. Interleukin-25 (IL-25) and monensin-resistant homolog 2 (MON-2) are only noted in UC, CD, pyoderma gangrenosum, and arthritis. Arachidonate 5-lipoxygenase (ALOX5) is involved in UC, CD, and arthritis. SLCO1B3 is exclusively involved with pyoderma gangrenosum, UC, and CD. As expected, TNF involvement is noted in CD, UC, PSC, and arthritis. Table 1 depicts the detailed result. Conclusion Our work has identified a distinctive set of genes involved in IBD and its associated extra-intestinal disease processes. These genes play crucial roles in mechanisms of immune response, inflammation, and apoptosis and further our understanding of this complex disease process. We postulate that these genes play a critical role at intersecting pathways involved in inflammatory bowel disease, and these novel molecules, their upstream and downstream effectors, are potential targets for future therapeutic agents.
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Affiliation(s)
- Sachin Mohan
- Department of Gastroenterology and Hepatology, University of Minnesota School of Medicine, St Paul, MN, USA.,Regions Hospital, Department of Gastroenterology and Hepatology, St Paul, MN, USA.,Health Partners Digestive Care Center, St Paul, MN, 55130, USA
| | - Shaffer Mok
- Division of Gastroenterology and Hepatology, University Hospital Digestive Health Institute, Westlake, OH 44145, USA
| | - Thomas Judge
- Division of Gastroenterology and Liver Diseases, Cooper University Hospital, Mount Laurel, NJ 08054, USA
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18
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Sun X, Tie HC, Chen B, Lu L. Glycans function as a Golgi export signal to promote the constitutive exocytic trafficking. J Biol Chem 2020; 295:14750-14762. [PMID: 32826314 PMCID: PMC7586228 DOI: 10.1074/jbc.ra120.014476] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/17/2020] [Indexed: 11/15/2022] Open
Abstract
Most proteins in the secretory pathway are glycosylated. However, the role of glycans in membrane trafficking is still unclear. Here, we discovered that transmembrane secretory cargos, such as interleukin 2 receptor α subunit or Tac, transferrin receptor, and cluster of differentiation 8a, unexpectedly displayed substantial Golgi localization when their O-glycosylation was compromised. By quantitatively measuring their Golgi residence times, we found that the observed Golgi localization of O-glycan–deficient cargos is due to their slow Golgi export. Using a superresolution microscopy method that we previously developed, we revealed that O-glycan–deficient Tac chimeras localize at the interior of the trans-Golgi cisternae. O-Glycans were observed to be both necessary and sufficient for the efficient Golgi export of Tac chimeras. By sequentially introducing O-glycosylation sites to ST6GAL1, we demonstrated that O-glycan's effect on Golgi export is probably additive. Finally, the finding that N-glycosylated GFP substantially reduces the Golgi residence time of a Tac chimera suggests that N-glycans might have a similar effect. Therefore, both O- and N-glycans might function as a generic Golgi export signal at the trans-Golgi to promote the constitutive exocytic trafficking.
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Affiliation(s)
- Xiuping Sun
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Hieng Chiong Tie
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Bing Chen
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore.
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19
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Fazeli G, Beer KB, Geisenhof M, Tröger S, König J, Müller-Reichert T, Wehman AM. Loss of the Major Phosphatidylserine or Phosphatidylethanolamine Flippases Differentially Affect Phagocytosis. Front Cell Dev Biol 2020; 8:648. [PMID: 32793595 PMCID: PMC7385141 DOI: 10.3389/fcell.2020.00648] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/29/2020] [Indexed: 12/31/2022] Open
Abstract
The lipids phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEth) are normally asymmetrically localized to the cytosolic face of membrane bilayers, but can both be externalized during diverse biological processes, including cell division, cell fusion, and cell death. Externalized lipids in the plasma membrane are recognized by lipid-binding proteins to regulate the clearance of cell corpses and other cell debris. However, it is unclear whether PtdSer and PtdEth contribute in similar or distinct ways to these processes. We discovered that disruption of the lipid flippases that maintain PtdSer or PtdEth asymmetry in the plasma membrane have opposite effects on phagocytosis in Caenorhabditis elegans embryos. Constitutive PtdSer externalization caused by disruption of the major PtdSer flippase TAT-1 led to increased phagocytosis of cell debris, sometimes leading to two cells engulfing the same debris. In contrast, PtdEth externalization caused by depletion of the major PtdEth flippase TAT-5 or its activator PAD-1 disrupted phagocytosis. These data suggest that PtdSer and PtdEth externalization have opposite effects on phagocytosis. Furthermore, externalizing PtdEth is associated with increased extracellular vesicle release, and we present evidence that the extent of extracellular vesicle accumulation correlates with the extent of phagocytic defects. Thus, a general loss of lipid asymmetry can have opposing impacts through different lipid subtypes simultaneously exerting disparate effects.
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Affiliation(s)
- Gholamreza Fazeli
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany.,Imaging Core Facility, Biocenter, University of Würzburg, Würzburg, Germany
| | - Katharina B Beer
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | | | - Sarah Tröger
- Imaging Core Facility, Biocenter, University of Würzburg, Würzburg, Germany
| | - Julia König
- Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | - Ann M Wehman
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany.,Department of Biological Sciences, University of Denver, Denver, CO, United States
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20
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Ali I, Yang WC. Why are ATP-driven microtubule minus-end directed motors critical to plants? An overview of plant multifunctional kinesins. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:524-536. [PMID: 32336322 DOI: 10.1071/fp19177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 01/13/2020] [Indexed: 06/11/2023]
Abstract
In plants, microtubule and actin cytoskeletons are involved in key processes including cell division, cell expansion, growth and development, biotic and abiotic stress, tropisms, hormonal signalling as well as cytoplasmic streaming in growing pollen tubes. Kinesin enzymes have a highly conserved motor domain for binding microtubule cytoskeleton assisting these motors to organise their own tracks, the microtubules by using chemical energy of ATP hydrolysis. In addition to this conserved binding site, kinesins possess non-conserved variable domains mediating structural and functional interaction of microtubules with other cell structures to perform various cellular jobs such as chromosome segregation, spindle formation and elongation, transport of organelles as well as microtubules-actins cross linking and microtubules sliding. Therefore, how the non-motor variable regions specify the kinesin function is of fundamental importance for all eukaryotic cells. Kinesins are classified into ~17 known families and some ungrouped orphans, of which ~13 families have been recognised in plants. Kinesin-14 family consisted of plant specific microtubules minus end-directed motors, are much diverse and unique to plants in the sense that they substitute the functions of animal dynein. In this review, we explore the functions of plant kinesins, especially from non-motor domains viewpoint, focussing mainly on recent work on the origin and functional diversity of motors that drive microtubule minus-end trafficking events.
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Affiliation(s)
- Iftikhar Ali
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; and The College of Advanced Agricultural Science, The University of Chinese Academy of Sciences, Beijing 100049, China; and Corresponding author.
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21
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Abstract
Lipid droplets (LDs) are fat storage organelles integral to energy homeostasis and a wide range of cellular processes. LDs physically and functionally interact with many partner organelles, including the ER, mitochondria, lysosomes, and peroxisomes. Recent findings suggest that the dynamics of LD inter-organelle contacts is in part controlled by LD intracellular motility. LDs can be transported directly by motor proteins along either actin filaments or microtubules, via Kinesin-1, Cytoplasmic Dynein, and type V Myosins. LDs can also be propelled indirectly, by hitchhiking on other organelles, cytoplasmic flows, and potentially actin polymerization. Although the anchors that attach motors to LDs remain elusive, other regulators of LD motility have been identified, ranging from modification of the tracks to motor co-factors to members of the perilipin family of LD proteins. Manipulating these regulatory pathways provides a tool to probe whether altered motility affects organelle contacts and has revealed that LD motility can promote interactions with numerous partners, with profound consequences for metabolism. LD motility can cause dramatic redistribution of LDs between a clustered and a dispersed state, resulting in altered organelle contacts and LD turnover. We propose that LD motility can thus promote switches in the metabolic state of a cell. Finally, LD motility is also important for LD allocation during cell division. In a number of animal embryos, uneven allocation results in a large difference in LD content in distinct daughter cells, suggesting cell-type specific LD needs.
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Affiliation(s)
- Marcus D Kilwein
- Department of Biology, University of Rochester, RC Box 270211, Rochester, NY 14627, USA
| | - M A Welte
- Department of Biology, University of Rochester, RC Box 270211, Rochester, NY 14627, USA
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