1
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Pulli K, Saarimäki-Vire J, Ahonen P, Liu X, Ibrahim H, Chandra V, Santambrogio A, Wang Y, Vaaralahti K, Iivonen AP, Känsäkoski J, Tommiska J, Kemkem Y, Varjosalo M, Vuoristo S, Andoniadou CL, Otonkoski T, Raivio T. A splice site variant in MADD affects hormone expression in pancreatic β cells and pituitary gonadotropes. JCI Insight 2024; 9:e167598. [PMID: 38775154 PMCID: PMC11141940 DOI: 10.1172/jci.insight.167598] [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: 06/27/2023] [Accepted: 04/12/2024] [Indexed: 06/02/2024] Open
Abstract
MAPK activating death domain (MADD) is a multifunctional protein regulating small GTPases RAB3 and RAB27, MAPK signaling, and cell survival. Polymorphisms in the MADD locus are associated with glycemic traits, but patients with biallelic variants in MADD manifest a complex syndrome affecting nervous, endocrine, exocrine, and hematological systems. We identified a homozygous splice site variant in MADD in 2 siblings with developmental delay, diabetes, congenital hypogonadotropic hypogonadism, and growth hormone deficiency. This variant led to skipping of exon 30 and in-frame deletion of 36 amino acids. To elucidate how this mutation causes pleiotropic endocrine phenotypes, we generated relevant cellular models with deletion of MADD exon 30 (dex30). We observed reduced numbers of β cells, decreased insulin content, and increased proinsulin-to-insulin ratio in dex30 human embryonic stem cell-derived pancreatic islets. Concordantly, dex30 led to decreased insulin expression in human β cell line EndoC-βH1. Furthermore, dex30 resulted in decreased luteinizing hormone expression in mouse pituitary gonadotrope cell line LβT2 but did not affect ontogeny of stem cell-derived GnRH neurons. Protein-protein interactions of wild-type and dex30 MADD revealed changes affecting multiple signaling pathways, while the GDP/GTP exchange activity of dex30 MADD remained intact. Our results suggest MADD-specific processes regulate hormone expression in pancreatic β cells and pituitary gonadotropes.
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Affiliation(s)
- Kristiina Pulli
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Jonna Saarimäki-Vire
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Pekka Ahonen
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Xiaonan Liu
- Institute of Biotechnology, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Hazem Ibrahim
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Vikash Chandra
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Alice Santambrogio
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
- Department of Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Yafei Wang
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Kirsi Vaaralahti
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Anna-Pauliina Iivonen
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
| | - Johanna Känsäkoski
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
- Department of Physiology, Faculty of Medicine
| | - Johanna Tommiska
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
- Department of Physiology, Faculty of Medicine
| | - Yasmine Kemkem
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Markku Varjosalo
- Institute of Biotechnology, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Sanna Vuoristo
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
- Department of Obstetrics and Gynecology; and
- HiLIFE, University of Helsinki, Helsinki, Finland
| | - Cynthia L. Andoniadou
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
- Department of Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
- New Children’s Hospital, Helsinki University Hospital, Pediatric Research Center, Helsinki, Finland
| | - Taneli Raivio
- Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, and
- Department of Physiology, Faculty of Medicine
- New Children’s Hospital, Helsinki University Hospital, Pediatric Research Center, Helsinki, Finland
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2
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Erol ÖD, Şenocak Ş, Aerts-Kaya F. The Role of Rab GTPases in the development of genetic and malignant diseases. Mol Cell Biochem 2024; 479:255-281. [PMID: 37060515 DOI: 10.1007/s11010-023-04727-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.
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Affiliation(s)
- Özgür Doğuş Erol
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Şimal Şenocak
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Fatima Aerts-Kaya
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey.
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey.
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3
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Ren JG, Xing B, Lv K, O’Keefe RA, Wu M, Wang R, Bauer KM, Ghazaryan A, Burslem GM, Zhang J, O’Connell RM, Pillai V, Hexner EO, Philips MR, Tong W. RAB27B controls palmitoylation-dependent NRAS trafficking and signaling in myeloid leukemia. J Clin Invest 2023; 133:e165510. [PMID: 37317963 PMCID: PMC10266782 DOI: 10.1172/jci165510] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/24/2023] [Indexed: 06/16/2023] Open
Abstract
RAS mutations are among the most prevalent oncogenic drivers in cancers. RAS proteins propagate signals only when associated with cellular membranes as a consequence of lipid modifications that impact their trafficking. Here, we discovered that RAB27B, a RAB family small GTPase, controlled NRAS palmitoylation and trafficking to the plasma membrane, a localization required for activation. Our proteomic studies revealed RAB27B upregulation in CBL- or JAK2-mutated myeloid malignancies, and its expression correlated with poor prognosis in acute myeloid leukemias (AMLs). RAB27B depletion inhibited the growth of CBL-deficient or NRAS-mutant cell lines. Strikingly, Rab27b deficiency in mice abrogated mutant but not WT NRAS-mediated progenitor cell growth, ERK signaling, and NRAS palmitoylation. Further, Rab27b deficiency significantly reduced myelomonocytic leukemia development in vivo. Mechanistically, RAB27B interacted with ZDHHC9, a palmitoyl acyltransferase that modifies NRAS. By regulating palmitoylation, RAB27B controlled c-RAF/MEK/ERK signaling and affected leukemia development. Importantly, RAB27B depletion in primary human AMLs inhibited oncogenic NRAS signaling and leukemic growth. We further revealed a significant correlation between RAB27B expression and sensitivity to MEK inhibitors in AMLs. Thus, our studies presented a link between RAB proteins and fundamental aspects of RAS posttranslational modification and trafficking, highlighting future therapeutic strategies for RAS-driven cancers.
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Affiliation(s)
- Jian-Gang Ren
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bowen Xing
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kaosheng Lv
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Biochemistry, School of Medicine at the Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Rachel A. O’Keefe
- Department of Medicine and Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, New York, USA
| | - Mengfang Wu
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ruoxing Wang
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kaylyn M. Bauer
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - Arevik Ghazaryan
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - George M. Burslem
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jing Zhang
- McArdle Laboratory for Cancer Research, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Ryan M. O’Connell
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - Vinodh Pillai
- Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Elizabeth O. Hexner
- Division of Hematology and Oncology, Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark R. Philips
- Department of Medicine and Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, New York, USA
| | - Wei Tong
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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4
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Ma Q, Beal JR, Song X, Bhurke A, Bagchi IC, Bagchi MK. Extracellular Vesicles Secreted by Mouse Decidual Cells Carry Critical Information for the Establishment of Pregnancy. Endocrinology 2022; 163:6758297. [PMID: 36219207 PMCID: PMC9761388 DOI: 10.1210/endocr/bqac165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Indexed: 11/19/2022]
Abstract
The mouse decidua secretes many factors that act in a paracrine/autocrine manner to critically control uterine decidualization, neovascularization, and tissue remodeling that ensure proper establishment of pregnancy. The precise mechanisms that dictate intercellular communications among the uterine cells during early pregnancy remain unknown. We recently reported that conditional deletion of the gene encoding the hypoxia-inducible transcription factor 2 alpha (Hif2α) in mouse uterus led to infertility. Here, we report that HIF2α in mouse endometrial stromal cells (MESCs) acts via the cellular trafficking regulator RAB27b to control the secretion of extracellular vesicles (EVs) during decidualization. We also found that Hif2α-regulated pathways influence the biogenesis of EVs. Proteomic analysis of EVs secreted by decidualizing MESCs revealed that they harbor a wide variety of protein cargoes whose composition changed as the decidualization process progressed. The EVs enhanced the differentiation capacity of MESCs and the production of angiogenic factors by these cells. We also established that matrix metalloproteinase-2, a prominent EV cargo protein, modulates uterine remodeling during decidualization. Collectively, our results support the concept that EVs are central to the mechanisms by which the decidual cells communicate with each other and other cell types within the uterus to facilitate successful establishment of pregnancy.
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Affiliation(s)
- Qiuyan Ma
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Jacob R Beal
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Xiangning Song
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Arpita Bhurke
- Carle Woese Institute of Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Indrani C Bagchi
- Correspondence: Indrani C. Bagchi, PhD, Departments of Comparative Biosciences, University of Illinois, Urbana-Champaign, Urbana, IL, USA. ; or Milan K. Bagchi, PhD, Departments of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.
| | - Milan K Bagchi
- Correspondence: Indrani C. Bagchi, PhD, Departments of Comparative Biosciences, University of Illinois, Urbana-Champaign, Urbana, IL, USA. ; or Milan K. Bagchi, PhD, Departments of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.
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5
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Deletion in chromosome 6 spanning alpha-synuclein and multimerin1 loci in the Rab27a/b double knockout mouse. Sci Rep 2022; 12:9837. [PMID: 35701443 PMCID: PMC9197848 DOI: 10.1038/s41598-022-13557-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 05/25/2022] [Indexed: 11/08/2022] Open
Abstract
We report an incidental 358.5 kb deletion spanning the region encoding for alpha-synuclein (αsyn) and multimerin1 (Mmrn1) in the Rab27a/Rab27b double knockout (DKO) mouse line previously developed by Tolmachova and colleagues in 2007. Western blot and RT-PCR studies revealed lack of αsyn expression at either the mRNA or protein level in Rab27a/b DKO mice. PCR of genomic DNA from Rab27a/b DKO mice demonstrated at least partial deletion of the Snca locus using primers targeted to exon 4 and exon 6. Most genes located in proximity to the Snca locus, including Atoh1, Atoh2, Gm5570, Gm4410, Gm43894, and Grid2, were shown not to be deleted by PCR except for Mmrn1. Using whole genomic sequencing, the complete deletion was mapped to chromosome 6 (60,678,870–61,037,354), a slightly smaller deletion region than that previously reported in the C57BL/6J substrain maintained by Envigo. Electron microscopy of cortex from these mice demonstrates abnormally enlarged synaptic terminals with reduced synaptic vesicle density, suggesting potential interplay between Rab27 isoforms and αsyn, which are all highly expressed at the synaptic terminal. Given this deletion involving several genes, the Rab27a/b DKO mouse line should be used with caution or with appropriate back-crossing to other C57BL/6J mouse substrain lines without this deletion.
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6
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Mizuno K, Izumi T. Munc13b stimulus-dependently accumulates on granuphilin-mediated, docked granules prior to fusion. Cell Struct Funct 2022; 47:31-41. [PMID: 35387942 PMCID: PMC10511056 DOI: 10.1247/csf.22005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/30/2022] [Indexed: 11/11/2022] Open
Abstract
The Rab27 effector granuphilin plays an indispensable role in stable docking of secretory granules to the plasma membrane by interacting with the complex of Munc18-1 and the fusion-incompetent, closed form of syntaxins-1~3. Although this process prevents spontaneous granule exocytosis, those docked granules actively fuse in parallel with other undocked granules after stimulation. Therefore, it is postulated that the closed form of syntaxins must be converted into the fusion-competent open form in a stimulus-dependent manner. Although Munc13 family proteins are generally thought to prime docked vesicles by facilitating conformational change in syntaxins, it is unknown which isoform acts in granuphilin-mediated, docked granule exocytosis. In the present study, we show that, although both Munc13a and Munc13b are expressed in mouse pancreatic islets and their beta-cell line MIN6, the silencing of Munc13b, but not that of Munc13a, severely affects glucose-induced insulin secretion. Furthermore, Munc13b accumulates on a subset of granules beneath the plasma membrane just prior to fusion during stimulation, whereas Munc13a is translocated to the plasma membrane where granules do not exist. When fluorescently labeled granuphilin was introduced to discriminate between molecularly docked granules and other undocked granules in living cells, Munc13b downregulation was observed to preferentially decrease the fusion of granuphilin-positive granules immobilized to the plasma membrane. These findings suggest that Munc13b promotes insulin exocytosis by clustering on molecularly docked granules in a stimulus-dependent manner.Key words: docking, insulin, live cell imaging, priming, TIRF microscopy.
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Affiliation(s)
- Kouichi Mizuno
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
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7
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Jamshidiha M, Lanyon-Hogg T, Sutherell CL, Craven GB, Tersa M, De Vita E, Brustur D, Pérez-Dorado I, Hassan S, Petracca R, Morgan RM, Sanz-Hernández M, Norman JC, Armstrong A, Mann DJ, Cota E, Tate EW. Identification of the first structurally validated covalent ligands of the small GTPase RAB27A. RSC Med Chem 2022; 13:150-155. [PMID: 35308027 PMCID: PMC8864489 DOI: 10.1039/d1md00225b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022] Open
Abstract
Rab27A is a small GTPase, which mediates transport and docking of secretory vesicles at the plasma membrane via protein-protein interactions (PPIs) with effector proteins. Rab27A promotes the growth and invasion of multiple cancer types such as breast, lung and pancreatic, by enhancing secretion of chemokines, metalloproteases and exosomes. The significant role of Rab27A in multiple cancer types and the minor role in adults suggest that Rab27A may be a suitable target to disrupt cancer metastasis. Similar to many GTPases, the flat topology of the Rab27A-effector PPI interface and the high affinity for GTP make it a challenging target for inhibition by small molecules. Reported co-crystal structures show that several effectors of Rab27A interact with the Rab27A SF4 pocket ('WF-binding pocket') via a conserved tryptophan-phenylalanine (WF) dipeptide motif. To obtain structural insight into the ligandability of this pocket, a novel construct was designed fusing Rab27A to part of an effector protein (fRab27A), allowing crystallisation of Rab27A in high throughput. The paradigm of KRas covalent inhibitor development highlights the challenge presented by GTPase proteins as targets. However, taking advantage of two cysteine residues, C123 and C188, that flank the WF pocket and are unique to Rab27A and Rab27B among the >60 Rab family proteins, we used the quantitative Irreversible Tethering (qIT) assay to identify the first covalent ligands for native Rab27A. The binding modes of two hits were elucidated by co-crystallisation with fRab27A, exemplifying a platform for identifying suitable lead fragments for future development of competitive inhibitors of the Rab27A-effector interaction interface, corroborating the use of covalent libraries to tackle challenging targets.
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Affiliation(s)
- Mostafa Jamshidiha
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Thomas Lanyon-Hogg
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | | | - Gregory B Craven
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
| | - Montse Tersa
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
| | - Elena De Vita
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Delia Brustur
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | | | - Sarah Hassan
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Rita Petracca
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Rhodri M Morgan
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
| | | | - Jim C Norman
- Beatson Institute for Cancer Research, Garscube Estate Glasgow G61 1BD UK
| | - Alan Armstrong
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - David J Mann
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
| | - Ernesto Cota
- Department of Life Sciences, Imperial College London London SW7 2AZ UK
| | - Edward W Tate
- Department of Chemistry, Imperial College London London W12 0BZ UK
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8
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Izumi T. In vivo Roles of Rab27 and Its Effectors in Exocytosis. Cell Struct Funct 2021; 46:79-94. [PMID: 34483204 PMCID: PMC10511049 DOI: 10.1247/csf.21043] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/31/2021] [Indexed: 11/11/2022] Open
Abstract
The monomeric GTPase Rab27 regulates exocytosis of a broad range of vesicles in multicellular organisms. Several effectors bind GTP-bound Rab27a and/or Rab27b on secretory vesicles to execute a series of exocytic steps, such as vesicle maturation, movement along microtubules, anchoring within the peripheral F-actin network, and tethering to the plasma membrane, via interactions with specific proteins and membrane lipids in a local milieu. Although Rab27 effectors generally promote exocytosis, they can also temporarily restrict it when they are involved in the rate-limiting step. Genetic alterations in Rab27-related molecules cause discrete diseases manifesting pigment dilution and immunodeficiency, and can also affect common diseases such as diabetes and cancer in complex ways. Although the function and mechanism of action of these effectors have been explored, it is unclear how multiple effectors act in coordination within a cell to regulate the secretory process as a whole. It seems that Rab27 and various effectors constitutively reside on individual vesicles to perform consecutive exocytic steps. The present review describes the unique properties and in vivo roles of the Rab27 system, and the functional relationship among different effectors coexpressed in single cells, with pancreatic beta cells used as an example.Key words: membrane trafficking, regulated exocytosis, insulin granules, pancreatic beta cells.
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Affiliation(s)
- Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371-8512, Japan
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9
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Yasui T, Miyata K, Nakatsuka C, Tsukise A, Gomi H. Morphological and histochemical characterization of the secretory epithelium in the canine lacrimal gland. Eur J Histochem 2021; 65. [PMID: 34726360 PMCID: PMC8581551 DOI: 10.4081/ejh.2021.3320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/14/2021] [Indexed: 11/24/2022] Open
Abstract
In the present study, the expression of secretory components and vesicular transport proteins in the canine lacrimal gland was examined and morphometric analysis was performed. The secretory epithelium consists of two types of secretory cells with different morphological features. The secretory cells constituting acinar units (type A cells) exhibited higher levels of glycoconjugates, including β-GlcNAc, than the other cell type constituting tubular units (type T cells). Immunoblot analysis revealed that antimicrobial proteins, such as lysozyme, lactoferrin and lactoperoxidase, Rab proteins (Rab3d, Rab27a and Rab27b) and soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins (VAMP2, VAMP4, VAMP8, syntaxin-1, syntaxin-4 and syntaxin-6), were expressed at various levels. We immunohistochemically demonstrated that the expression patterns of lysozyme, lactoferrin, Rab27a, Rab27b, VAMP4, VAMP8 and syntaxin-6 differed depending on the secretory cell type. Additionally, in type T cells, VAMP4 was confined to a subpopulation of secretory granules, while VAMP8 was detected in almost all of them. The present study displayed the morphological and histochemical characteristics of the secretory epithelium in the canine lacrimal gland. These findings will help elucidate the species-specific properties of this gland.
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Affiliation(s)
- Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa.
| | - Kenya Miyata
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa.
| | - Chie Nakatsuka
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa.
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa.
| | - Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa.
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10
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Pournaghi M, Khodavirdilou R, Saadatlou MAE, Nasimi FS, Yousefi S, Mobarak H, Darabi M, Shahnazi V, Rahbarghazi R, Mahdipour M. Effect of melatonin on exosomal dynamics in bovine cumulus cells. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Arias-Hervert ER, Xu N, Njus M, Murphy GG, Hou Y, Williams JA, Lentz SI, Ernst SA, Stuenkel EL. Actions of Rab27B-GTPase on mammalian central excitatory synaptic transmission. Physiol Rep 2021; 8:e14428. [PMID: 32358861 PMCID: PMC7195558 DOI: 10.14814/phy2.14428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/20/2022] Open
Abstract
Members of the Rab3 gene family are considered central to membrane trafficking of synaptic vesicles at mammalian central excitatory synapses. Recent evidence, however, indicates that the Rab27B-GTPase, which is highly homologous to the Rab3 family, is also enriched on SV membranes and co-localize with Rab3A and Synaptotagmin at presynaptic terminals. While functional roles of Rab3A have been well-established, little functional information exists on the role of Rab27B in synaptic transmission. Here we report on functional effects of Rab27B at SC-CA1 and DG-MF hippocampal synapses. The data establish distinct functional actions of Rab27B and demonstrate functions of Rab27B that differ between SC-CA1 and DG-MF synapses. Rab27B knockout reduced frequency facilitation compared to wild-type (WT) controls at the DG/MF-CA3 synaptic region, while increasing facilitation at the SC-CA1 synaptic region. Remarkably, Rab27B KO resulted in a complete elimination of LTP at the MF-CA3 synapse with no effect at the SC-CA1 synapse. These actions are similar to those previously reported for Rab3A KO. Specificity of action on LTP to Rab27B was confirmed as LTP was rescued in response to lentiviral infection and expression of human Rab27B, but not to GFP, in the DG in the Rab27B KO mice. Notably, the effect of Rab27B KO on MF-CA3 LTP occurred in spite of continued expression of Rab3A in the Rab27B KO. Overall, the results provide a novel perspective in suggesting that Rab27B and Rab3A act synergistically, perhaps via sequential effector recruitment or signaling for presynaptic LTP expression in this hippocampal synaptic region.
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Affiliation(s)
- Erwin R Arias-Hervert
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Nicole Xu
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Meredith Njus
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Geoff G Murphy
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Yanan Hou
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - John A Williams
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA.,Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Stephen I Lentz
- Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Stephen A Ernst
- Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Edward L Stuenkel
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
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12
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Abu-Libdeh B, Mor-Shaked H, Atawna AA, Gillis D, Halstuk O, Shaul-Lotan N, Slae M, Sultan M, Meiner V, Elpeleg O, Harel T. Homozygous variant in MADD, encoding a Rab guanine nucleotide exchange factor, results in pleiotropic effects and a multisystemic disorder. Eur J Hum Genet 2021; 29:977-987. [PMID: 33723354 DOI: 10.1038/s41431-021-00844-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 01/20/2021] [Accepted: 02/24/2021] [Indexed: 12/20/2022] Open
Abstract
Rab proteins coordinate inter-organellar vesicle-mediated transport, facilitating intracellular communication, protein recycling, and signaling processes. Dysfunction of Rab proteins or their direct interactors leads to a wide range of diseases with diverse manifestations. We describe seven individuals from four consanguineous Arab Muslim families with an infantile-lethal syndrome, including failure to thrive (FTT), chronic diarrhea, neonatal respiratory distress, variable pituitary dysfunction, and distal arthrogryposis. Exome sequencing analysis in the independent families, followed by an internal gene-matching process using a local exome database, identified a homozygous splice-site variant in MADD (c.2816 + 1 G > A) on a common haplotype. The variant segregated with the disease in all available family members. Determination of cDNA sequence verified single exon skipping, resulting in an out-of-frame deletion. MADD encodes a Rab guanine nucleotide exchange factor (GEF), which activates RAB3 and RAB27A/27B and is thus a crucial regulator of neuromuscular junctions and endocrine secretory granule release. Moreover, MADD protects cells from caspase-mediated TNF-α-induced apoptosis. The combined roles of MADD and its downstream effectors correlate with the phenotypic spectrum of disease, and call for additional studies to confirm the pathogenic mechanism and to investigate possible therapeutic avenues through modulation of TNF-α signaling.
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Affiliation(s)
- Bassam Abu-Libdeh
- Department of Pediatrics, Makassed Hospital and Faculty of Medicine, Al-Quds University, East Jerusalem, Palestine
| | - Hagar Mor-Shaked
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel.,Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Amir A Atawna
- Department of Neonatology, Makassed Hospital, East Jerusalem, Palestine
| | - David Gillis
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Pediatrics, Hadassah Medical Center, Jerusalem, Israel
| | - Orli Halstuk
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel.,Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shaul-Lotan
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
| | - Mordechai Slae
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Pediatrics, Hadassah Medical Center, Jerusalem, Israel
| | - Mutaz Sultan
- Department of Pediatrics, Makassed Hospital and Faculty of Medicine, Al-Quds University, East Jerusalem, Palestine
| | - Vardiella Meiner
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel.,Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel.,Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel. .,Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
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13
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Gomi H, Hinata A, Yasui T, Torii S, Hosaka M. Expression Pattern of the LacZ Reporter in Secretogranin III Gene-trapped Mice. J Histochem Cytochem 2021; 69:229-243. [PMID: 33622062 DOI: 10.1369/0022155421996845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Secretogranin III (SgIII) is a granin protein involved in secretory granule formation in peptide-hormone-producing endocrine cells. In this study, we analyzed the expression of the LacZ reporter in the SgIII knockout mice produced by gene trapping (SgIII-gtKO) for the purpose of comprehensively clarifying the expression patterns of SgIII at the cell and tissue levels. In the endocrine tissues of SgIII-gtKO mice, LacZ expression was observed in the pituitary gland, adrenal medulla, and pancreatic islets, where SgIII expression has been canonically revealed. LacZ expression was extensively observed in brain regions, especially in the cerebral cortex, hippocampus, hypothalamic nuclei, cerebellum, and spinal cord. In peripheral nervous tissues, LacZ expression was observed in the retina, optic nerve, and trigeminal ganglion. LacZ expression was particularly prominent in astrocytes, in addition to neurons and ependymal cells. In the cerebellum, at least four cell types expressed SgIII under basal conditions. The expression of SgIII in the glioma cell lines C6 and RGC-6 was enhanced by excitatory glutamate treatment. It also became clear that the expression level of SgIII varied among neuron and astrocyte subtypes. These results suggest that SgIII is involved in glial cell function, in addition to neuroendocrine functions, in the nervous system.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Airi Hinata
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Seiji Torii
- Center for Food Science and Wellness, Gunma University, Maebashi, Japan
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
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14
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Okunishi K, Wang H, Suzukawa M, Ishizaki R, Kobayashi E, Kihara M, Abe T, Miyazaki JI, Horie M, Saito A, Saito H, Nakae S, Izumi T. Exophilin-5 regulates allergic airway inflammation by controlling IL-33-mediated Th2 responses. J Clin Invest 2021; 130:3919-3935. [PMID: 32240120 DOI: 10.1172/jci127839] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/31/2020] [Indexed: 12/12/2022] Open
Abstract
A common variant in the RAB27A gene in adults was recently found to be associated with the fractional exhaled nitric oxide level, a marker of eosinophilic airway inflammation. The small GTPase Rab27 is known to regulate intracellular vesicle traffic, although its role in allergic responses is unclear. We demonstrated that exophilin-5, a Rab27-binding protein, was predominantly expressed in both of the major IL-33 producers, lung epithelial cells, and the specialized IL-5 and IL-13 producers in the CD44hiCD62LloCXCR3lo pathogenic Th2 cell population in mice. Exophilin-5 deficiency increased stimulant-dependent damage and IL-33 secretion by lung epithelial cells. Moreover, it enhanced IL-5 and IL-13 production in response to TCR and IL-33 stimulation from a specific subset of pathogenic Th2 cells that expresses a high level of IL-33 receptor, which exacerbated allergic airway inflammation in a mouse model of asthma. Mechanistically, exophilin-5 regulates extracellular superoxide release, intracellular ROS production, and phosphoinositide 3-kinase activity by controlling intracellular trafficking of Nox2-containing vesicles, which seems to prevent the overactivation of pathogenic Th2 cells mediated by IL-33. This is the first report to our knowledge to establish the significance of the Rab27-related protein exophilin-5 in the development of allergic airway inflammation, and provides insights into the pathophysiology of asthma.
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Affiliation(s)
- Katsuhide Okunishi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hao Wang
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Maho Suzukawa
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan.,Division of Respiratory Medicine and Allergology, Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Ray Ishizaki
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Eri Kobayashi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Miho Kihara
- Laboratory for Animal Resource Development and
| | - Takaya Abe
- Laboratory for Animal Resource Development and.,Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Jun-Ichi Miyazaki
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Masafumi Horie
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Akira Saito
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hirohisa Saito
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Susumu Nakae
- Laboratory of Systems Biology, Center for Experimental Medicine and Systems Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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15
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Brusilovsky M, Rochman M, Azouz NP, Mack LE, Rothenberg ME. Uncovering the secretes of allergic inflammation. J Clin Invest 2021; 130:3419-3421. [PMID: 32510472 DOI: 10.1172/jci138343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Allergic asthma is a chronic inflammatory lung disease associated with increased cytokine secretion. Aspects of airway inflammation are also linked to a common genetic variant that corresponds to the small GTPase, Rab27, a protein involved in vesicular trafficking in immune cells. However, the mechanisms by which Rab27 contributes to airway inflammation and cytokine release remain ambiguous. In this issue of the JCI, Okunishi et al. explored the role that the Rab27 effector, exophilin-5, has in allergic inflammation. Exophilin-5-deficient mice and asthma mouse models revealed that exophilin-5 regulates IL-33 production and the Th2 response. Notably, exophilin-5 deletion enhanced IL-33 release and pathogenic Th2 responsiveness through the mTOR pathway and altered intracellular IL-33 trafficking. This work provides insights into the molecular mechanisms that underlie inflammatory lung disease.
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Affiliation(s)
- Michael Brusilovsky
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Mark Rochman
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nurit P Azouz
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Lydia E Mack
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Marc E Rothenberg
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
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16
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Homma Y, Hiragi S, Fukuda M. Rab family of small GTPases: an updated view on their regulation and functions. FEBS J 2021; 288:36-55. [PMID: 32542850 PMCID: PMC7818423 DOI: 10.1111/febs.15453] [Citation(s) in RCA: 214] [Impact Index Per Article: 71.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/27/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022]
Abstract
The Rab family of small GTPases regulates intracellular membrane trafficking by orchestrating the biogenesis, transport, tethering, and fusion of membrane-bound organelles and vesicles. Like other small GTPases, Rabs cycle between two states, an active (GTP-loaded) state and an inactive (GDP-loaded) state, and their cycling is catalyzed by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Because an active form of each Rab localizes on a specific organelle (or vesicle) and recruits various effector proteins to facilitate each step of membrane trafficking, knowing when and where Rabs are activated and what effectors Rabs recruit is crucial to understand their functions. Since the discovery of Rabs, they have been regarded as one of the central hubs for membrane trafficking, and numerous biochemical and genetic studies have revealed the mechanisms of Rab functions in recent years. The results of these studies have included the identification and characterization of novel GEFs, GAPs, and effectors, as well as post-translational modifications, for example, phosphorylation, of Rabs. Rab functions beyond the simple effector-recruiting model are also emerging. Furthermore, the recently developed CRISPR/Cas technology has enabled acceleration of knockout analyses in both animals and cultured cells and revealed previously unknown physiological roles of many Rabs. In this review article, we provide the most up-to-date and comprehensive lists of GEFs, GAPs, effectors, and knockout phenotypes of mammalian Rabs and discuss recent findings in regard to their regulation and functions.
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Affiliation(s)
- Yuta Homma
- Laboratory of Membrane Trafficking MechanismsDepartment of Integrative Life SciencesGraduate School of Life SciencesTohoku UniversitySendaiJapan
| | - Shu Hiragi
- Laboratory of Membrane Trafficking MechanismsDepartment of Integrative Life SciencesGraduate School of Life SciencesTohoku UniversitySendaiJapan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking MechanismsDepartment of Integrative Life SciencesGraduate School of Life SciencesTohoku UniversitySendaiJapan
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17
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Dong X, Bai X, Ni J, Zhang H, Duan W, Graham P, Li Y. Exosomes and breast cancer drug resistance. Cell Death Dis 2020; 11:987. [PMID: 33203834 PMCID: PMC7673022 DOI: 10.1038/s41419-020-03189-z] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022]
Abstract
Drug resistance is a daunting challenge in the treatment of breast cancer (BC). Exosomes, as intercellular communicative vectors in the tumor microenvironment, play an important role in BC progression. With the in-depth understanding of tumor heterogeneity, an emerging role of exosomes in drug resistance has attracted extensive attention. The functional proteins or non-coding RNAs contained in exosomes secreted from tumor and stromal cells mediate drug resistance by regulating drug efflux and metabolism, pro-survival signaling, epithelial–mesenchymal transition, stem-like property, and tumor microenvironmental remodeling. In this review, we summarize the underlying associations between exosomes and drug resistance of BC and discuss the unique biogenesis of exosomes, the change of exosome cargo, and the pattern of release by BC cells in response to drug treatment. Moreover, we propose exosome as a candidate biomarker in predicting and monitoring the therapeutic drug response of BC and as a potential target or carrier to reverse the drug resistance of BC.
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Affiliation(s)
- Xingli Dong
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, 150081, Harbin, Heilongjiang, China.,St George and Sutherland Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW, 2052, Australia
| | - Xupeng Bai
- St George and Sutherland Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW, 2052, Australia.,Cancer Care Centre, St. George Hospital, Kogarah, NSW, 2217, Australia
| | - Jie Ni
- St George and Sutherland Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW, 2052, Australia.,Cancer Care Centre, St. George Hospital, Kogarah, NSW, 2217, Australia
| | - Hao Zhang
- Institute of Precision Cancer Medicine and Pathology and Department of Pathology, Jinan University Medical College, 510630, Guangzhou, China
| | - Wei Duan
- School of Medicine and Centre for Molecular and Medical Research, Deakin University, Waurn Ponds, VIC, 3216, Australia
| | - Peter Graham
- St George and Sutherland Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW, 2052, Australia.,Cancer Care Centre, St. George Hospital, Kogarah, NSW, 2217, Australia
| | - Yong Li
- St George and Sutherland Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW, 2052, Australia. .,Cancer Care Centre, St. George Hospital, Kogarah, NSW, 2217, Australia. .,School of Basic Medicine Sciences, Zhengzhou University, 450001, Henan, China.
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18
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Olejarz W, Kubiak-Tomaszewska G, Chrzanowska A, Lorenc T. Exosomes in Angiogenesis and Anti-angiogenic Therapy in Cancers. Int J Mol Sci 2020; 21:ijms21165840. [PMID: 32823989 PMCID: PMC7461570 DOI: 10.3390/ijms21165840] [Citation(s) in RCA: 143] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/09/2020] [Accepted: 08/12/2020] [Indexed: 12/13/2022] Open
Abstract
Angiogenesis is the process through which new blood vessels are formed from pre-existing ones. Exosomes are involved in angiogenesis in cancer progression by transporting numerous pro-angiogenic biomolecules like vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), and microRNAs. Exosomes promote angiogenesis by suppressing expression of factor-inhibiting hypoxia-inducible factor 1 (HIF-1). Uptake of tumor-derived exosomes (TEX) by normal endothelial cells activates angiogenic signaling pathways in endothelial cells and stimulates new vessel formation. TEX-driven cross-talk of mesenchymal stem cells (MSCs) with immune cells blocks their anti-tumor activity. Effective inhibition of tumor angiogenesis may arrest tumor progression. Bevacizumab, a VEGF-specific antibody, was the first antiangiogenic agent to enter the clinic. The most important clinical problem associated with cancer therapy using VEGF- or VEFGR-targeting agents is drug resistance. Combined strategies based on angiogenesis inhibitors and immunotherapy effectively enhances therapies in various cancers, but effective treatment requires further research.
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Affiliation(s)
- Wioletta Olejarz
- Department of Biochemistry and Pharmacogenomics, Faculty of Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland; (W.O.); (G.K.-T.)
- Centre for Preclinical Research, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Grażyna Kubiak-Tomaszewska
- Department of Biochemistry and Pharmacogenomics, Faculty of Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland; (W.O.); (G.K.-T.)
- Centre for Preclinical Research, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Alicja Chrzanowska
- Chair and Department of Biochemistry, Medical University of Warsaw, ul. Banacha 1, 02-097 Warsaw, Poland;
| | - Tomasz Lorenc
- 1st Department of Clinical Radiology, Medical University of Warsaw, ul. Chałubińskiego 5, 02-004 Warsaw, Poland
- Correspondence: ; Tel.: +48-22-502-1073
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19
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Schneeberger PE, Kortüm F, Korenke GC, Alawi M, Santer R, Woidy M, Buhas D, Fox S, Juusola J, Alfadhel M, Webb BD, Coci EG, Abou Jamra R, Siekmeyer M, Biskup S, Heller C, Maier EM, Javaher-Haghighi P, Bedeschi MF, Ajmone PF, Iascone M, Peeters H, Ballon K, Jaeken J, Rodríguez Alonso A, Palomares-Bralo M, Santos-Simarro F, Meuwissen MEC, Beysen D, Kooy RF, Houlden H, Murphy D, Doosti M, Karimiani EG, Mojarrad M, Maroofian R, Noskova L, Kmoch S, Honzik T, Cope H, Sanchez-Valle A, Gelb BD, Kurth I, Hempel M, Kutsche K. Biallelic MADD variants cause a phenotypic spectrum ranging from developmental delay to a multisystem disorder. Brain 2020; 143:2437-2453. [PMID: 32761064 PMCID: PMC7447524 DOI: 10.1093/brain/awaa204] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 12/22/2022] Open
Abstract
In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.
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Affiliation(s)
- Pauline E Schneeberger
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Georg Christoph Korenke
- Klinik für Neuropädiatrie und angeborene Stoffwechselerkrankungen, Klinikum Oldenburg, Oldenburg, Germany
| | - Malik Alawi
- Bioinformatics Core Unit, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mathias Woidy
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniela Buhas
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, Canada
- Human Genetics Department, McGill University, Montreal, Canada
| | - Stephanie Fox
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, Canada
- Human Genetics Department, McGill University, Montreal, Canada
| | | | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdullah specialized Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Bryn D Webb
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, USA
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Emanuele G Coci
- Department for Neuropediatrics, University Children's Hospital, Ruhr University Bochum, Bochum, Germany
- Department of Pediatrics, Prignitz Hospital, Brandenburg Medical School, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University Medical Center Leipzig, Leipzig, Germany
| | - Manuela Siekmeyer
- Universitätsklinikum Leipzig - AöR, University of Leipzig, Hospital for Children and Adolescents, Leipzig, Germany
| | - Saskia Biskup
- CeGaT GmbH and Praxis für Humangenetik Tübingen, Tübingen, Germany
| | - Corina Heller
- CeGaT GmbH and Praxis für Humangenetik Tübingen, Tübingen, Germany
| | - Esther M Maier
- Dr. von Hauner Children's Hospital, University of Munich, Munich, Germany
| | | | - Maria F Bedeschi
- Medical Genetic Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Paola F Ajmone
- Child and Adolescent Neuropsychiatric Unit, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Iascone
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Hilde Peeters
- Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Katleen Ballon
- Centre for Developmental Disabilities, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Jaak Jaeken
- Center for Metabolic Diseases, KU Leuven, Leuven, Belgium
| | - Aroa Rodríguez Alonso
- Unidad de Patología Compleja, Servicio de Pediatría, Hospital Universitario La Paz, Madrid, Spain
| | - María Palomares-Bralo
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz, IdiPAZ, CIBERER, ISCIII, Madrid, Spain
| | - Fernando Santos-Simarro
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz, IdiPAZ, CIBERER, ISCIII, Madrid, Spain
| | | | - Diane Beysen
- Department of Pediatric Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - David Murphy
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | | | - Ehsan G Karimiani
- Next Generation Genetic Polyclinic, Mashhad, Iran
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St. George's, University, London, UK
| | - Majid Mojarrad
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Genetic Center of Khorasan Razavi, Mashhad, Iran
| | - Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Lenka Noskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Stanislav Kmoch
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Tomas Honzik
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Heidi Cope
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Amarilis Sanchez-Valle
- Division of Genetics and Metabolism, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Bruce D Gelb
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, USA
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
- Institute of Human Genetics, Jena University Hospital, Jena, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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20
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Rab27a Contributes to the Processing of Inflammatory Pain in Mice. Cells 2020; 9:cells9061488. [PMID: 32570938 PMCID: PMC7349490 DOI: 10.3390/cells9061488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/13/2020] [Accepted: 06/15/2020] [Indexed: 12/26/2022] Open
Abstract
Tissue injury and inflammation may result in chronic pain, a severe debilitating disease that is associated with great impairment of quality of life. An increasing body of evidence indicates that members of the Rab family of small GTPases contribute to pain processing; however, their specific functions remain poorly understood. Here, we found using immunofluorescence staining and in situ hybridization that the small GTPase Rab27a is highly expressed in sensory neurons and in the superficial dorsal horn of the spinal cord of mice. Rab27a mutant mice, which carry a single-nucleotide missense mutation of Rab27a leading to the expression of a nonfunctional protein, show reduced mechanical hyperalgesia and spontaneous pain behavior in inflammatory pain models, while their responses to acute noxious mechanical and thermal stimuli is not affected. Our study uncovers a previously unrecognized function of Rab27a in the processing of persistent inflammatory pain in mice.
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21
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A hypoxia-induced Rab pathway regulates embryo implantation by controlled trafficking of secretory granules. Proc Natl Acad Sci U S A 2020; 117:14532-14542. [PMID: 32513733 DOI: 10.1073/pnas.2000810117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Implantation is initiated when an embryo attaches to the uterine luminal epithelium and subsequently penetrates into the underlying stroma to firmly embed in the endometrium. These events are followed by the formation of an extensive vascular network in the stroma that supports embryonic growth and ensures successful implantation. Interestingly, in many mammalian species, these processes of early pregnancy occur in a hypoxic environment. However, the mechanisms underlying maternal adaptation to hypoxia during early pregnancy remain unclear. In this study, using a knockout mouse model, we show that the transcription factor hypoxia-inducible factor 2 alpha (Hif2α), which is induced in subluminal stromal cells at the time of implantation, plays a crucial role during early pregnancy. Indeed, when preimplantation endometrial stromal cells are exposed to hypoxic conditions in vitro, we observed a striking enhancement in HIF2α expression. Further studies revealed that HIF2α regulates the expression of several metabolic and protein trafficking factors, including RAB27B, at the onset of implantation. RAB27B is a member of the Rab family of GTPases that allows controlled release of secretory granules. These granules are involved in trafficking MMP-9 from the stroma to the epithelium to promote luminal epithelial remodeling during embryo invasion. As pregnancy progresses, the HIF2α-RAB27B pathway additionally mediates crosstalk between stromal and endothelial cells via VEGF granules, developing the vascular network critical for establishing pregnancy. Collectively, our study provides insights into the intercellular communication mechanisms that operate during adaptation to hypoxia, which is essential for embryo implantation and establishment of pregnancy.
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22
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Oncogenic effects of RAB27B through exosome independent function in renal cell carcinoma including sunitinib-resistant. PLoS One 2020; 15:e0232545. [PMID: 32379831 PMCID: PMC7205224 DOI: 10.1371/journal.pone.0232545] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 04/16/2020] [Indexed: 12/11/2022] Open
Abstract
Exosomes are 40–100 nm nano-sized extracellular vesicles. They are released from many cell types and move into the extracellular space, thereby transferring their components to recipient cells. Exosomes are receiving increasing attention as novel structures participating in intracellular communication. RAB27B is one of the leading proteins involved in exosome secretion, and oncogenic effects have been reported in several cancers. In recent years, molecularly targeted agents typified by sunitinib are widely used for the treatment of metastatic or recurrent renal cell carcinoma (RCC). However, intrinsic or acquired resistance to sunitinib has become a major issue. The present study aimed to elucidate the role of RAB27B in RCC including sunitinib-resistant and its role in exosomes. Bioinformatic analyses revealed that high expression of RAB27B correlates with progression of RCC. The expression of RAB27B protein in RCC cell lines was significantly enhanced compared with that in normal kidney cell lines. Furthermore, RAB27B protein expression was enhanced in all of the tested sunitinib-resistant RCC cell lines compared to parental cells. Although no specific effect of RAB27B on exosomes was identified in RCC cells, loss-of-function studies demonstrated that knockdown of RAB27B suppressed cell proliferation, migration and invasive activities. Moreover, anti-tumor effects of RAB27B downregulation were also observed in sunitinib-resistant RCC cells. RNA sequence and pathway analysis suggested that the oncogenic effects of RAB27B might be associated with MAPK and VEGF signaling pathways. These results showed that RAB27B is a prognostic marker and a novel therapeutic target in sunitinib-sensitive and -resistant RCCs. Further analyses should improve our understanding of sunitinib resistance in RCC.
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23
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Underwood R, Wang B, Carico C, Whitaker RH, Placzek WJ, Yacoubian TA. The GTPase Rab27b regulates the release, autophagic clearance, and toxicity of α-synuclein. J Biol Chem 2020; 295:8005-8016. [PMID: 32350025 DOI: 10.1074/jbc.ra120.013337] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/24/2020] [Indexed: 12/25/2022] Open
Abstract
α-Synuclein (αsyn) is the primary component of proteinaceous aggregates termed Lewy bodies that pathologically define synucleinopathies including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). αsyn is hypothesized to spread through the brain in a prion-like fashion by misfolded protein forming a template for aggregation of endogenous αsyn. The cell-to-cell release and uptake of αsyn are considered important processes for its prion-like spread. Rab27b is one of several GTPases essential to the endosomal-lysosomal pathway and is implicated in protein secretion and clearance, but its role in αsyn spread has yet to be characterized. In this study, we used a paracrine αsyn in vitro neuronal model to test the impact of Rab27b on αsyn release, clearance, and toxicity. shRNA-mediated knockdown (KD) of Rab27b increased αsyn-mediated paracrine toxicity. Rab27b reduced αsyn release primarily through nonexosomal pathways, but the αsyn released after Rab27b KD was of higher-molecular-weight species, as determined by size-exclusion chromatography. Rab27b KD increased intracellular levels of insoluble αsyn and led to an accumulation of endogenous light chain 3 (LC3)-positive puncta. Rab27b KD also decreased LC3 turnover after treatment with an autophagosome-lysosome fusion inhibitor, chloroquine, indicating that Rab27b KD induces a defect in autophagic flux. Rab27b protein levels were increased in brain lysates obtained from postmortem tissues of individuals with PD and DLB compared with healthy controls. These data indicate a role for Rab27b in the release, clearance, and toxicity of αsyn and, ultimately, in the pathogenesis of synucleinopathies.
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Affiliation(s)
- Rachel Underwood
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Bing Wang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Christine Carico
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Robert H Whitaker
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - William J Placzek
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Talene A Yacoubian
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
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24
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Stephens DC, Osunsanmi N, Sochacki KA, Powell TW, Taraska JW, Harris DA. Spatiotemporal organization and protein dynamics involved in regulated exocytosis of MMP-9 in breast cancer cells. J Gen Physiol 2019; 151:1386-1403. [PMID: 31676484 PMCID: PMC6888755 DOI: 10.1085/jgp.201812299] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 09/30/2019] [Indexed: 12/22/2022] Open
Abstract
This paper describes the dynamics of proteins and lipids during exocytosis of MMP-9 from cancer cells in real time using fluorescence microscopy. Stephens et al. find that core exocytic proteins, accessory proteins, and lipids are involved at sites of secretory vesicle fusion. Altered regulation of exocytosis is an important mechanism controlling many diseases, including cancer. Defects in exocytosis have been implicated in many cancer cell types and are generally attributed to mutations in cellular transport, trafficking, and assembly of machinery necessary for exocytosis of secretory vesicle cargo. In these cancers, up-regulation of trafficking and secretion of matrix metalloproteinase-9 (MMP-9), a proteolytic enzyme, is responsible for degrading the extracellular matrix, a necessary step in tumor progression. Using TIRF microscopy, we identified proteins associated with secretory vesicles containing MMP-9 and imaged the local dynamics of these proteins at fusion sites during regulated exocytosis of MMP-9 from MCF-7 breast cancer cells. We found that many regulators of exocytosis, including several Rab GTPases, Rab effector proteins, and SNARE/SNARE modulator proteins, are stably assembled on docked secretory vesicles before exocytosis. At the moment of fusion, many of these components are quickly lost from the vesicle, while several endocytic proteins and lipids are simultaneously recruited to exocytic sites at precisely that moment. Our findings provide insight into the dynamic behavior of key core exocytic proteins, accessory proteins, lipids, and some endocytic proteins at single sites of secretory vesicle fusion in breast cancer cells.
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Affiliation(s)
| | | | - Kem A Sochacki
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Tyrel W Powell
- Department of Chemistry, Howard University, Washington, DC
| | - Justin W Taraska
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
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25
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Rafi SK, Fernández-Jaén A, Álvarez S, Nadeau OW, Butler MG. High Functioning Autism with Missense Mutations in Synaptotagmin-Like Protein 4 (SYTL4) and Transmembrane Protein 187 (TMEM187) Genes: SYTL4- Protein Modeling, Protein-Protein Interaction, Expression Profiling and MicroRNA Studies. Int J Mol Sci 2019; 20:E3358. [PMID: 31323913 PMCID: PMC6651166 DOI: 10.3390/ijms20133358] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/10/2019] [Accepted: 06/17/2019] [Indexed: 01/31/2023] Open
Abstract
We describe a 7-year-old male with high functioning autism spectrum disorder (ASD) and maternally-inherited rare missense variant of Synaptotagmin-like protein 4 (SYTL4) gene (Xq22.1; c.835C>T; p.Arg279Cys) and an unknown missense variant of Transmembrane protein 187 (TMEM187) gene (Xq28; c.708G>T; p. Gln236His). Multiple in-silico predictions described in our study indicate a potentially damaging status for both X-linked genes. Analysis of predicted atomic threading models of the mutant and the native SYTL4 proteins suggest a potential structural change induced by the R279C variant which eliminates the stabilizing Arg279-Asp60 salt bridge in the N-terminal half of the SYTL4, affecting the functionality of the protein's critical RAB-Binding Domain. In the European (Non-Finnish) population, the allele frequency for this variant is 0.00042. The SYTL4 gene is known to directly interact with several members of the RAB family of genes, such as, RAB27A, RAB27B, RAB8A, and RAB3A which are known autism spectrum disorder genes. The SYTL4 gene also directly interacts with three known autism genes: STX1A, SNAP25 and STXBP1. Through a literature-based analytical approach, we identified three of five (60%) autism-associated serum microRNAs (miRs) with high predictive power among the total of 298 mouse Sytl4 associated/predicted microRNA interactions. Five of 13 (38%) miRs were differentially expressed in serum from ASD individuals which were predicted to interact with the mouse equivalent Sytl4 gene. TMEM187 gene, like SYTL4, is a protein-coding gene that belongs to a group of genes which host microRNA genes in their introns or exons. The novel Q236H amino acid variant in the TMEM187 in our patient is near the terminal end region of the protein which is represented by multiple sequence alignments and hidden Markov models, preventing comparative structural analysis of the variant harboring region. Like SYTL4, the TMEM187 gene is expressed in the brain and interacts with four known ASD genes, namely, HCFC1; TMLHE; MECP2; and GPHN. TMM187 is in linkage with MECP2, which is a well-known determinant of brain structure and size and is a well-known autism gene. Other members of the TMEM gene family, TMEM132E and TMEM132D genes are associated with bipolar and panic disorders, respectively, while TMEM231 is a known syndromic autism gene. Together, TMEM187 and SYTL4 genes directly interact with recognized important ASD genes, and their mRNAs are found in extracellular vesicles in the nervous system and stimulate target cells to translate into active protein. Our evidence shows that both these genes should be considered as candidate genes for autism. Additional biological testing is warranted to further determine the pathogenicity of these gene variants in the causation of autism.
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Affiliation(s)
- Syed K Rafi
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | | | - Sara Álvarez
- Genomics and Medicine, NIM Genetics, 28108 Madrid, Spain
| | - Owen W Nadeau
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Merlin G Butler
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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26
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Abstract
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed.
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27
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Li Z, Fang R, Fang J, He S, Liu T. Functional implications of Rab27 GTPases in Cancer. Cell Commun Signal 2018; 16:44. [PMID: 30081925 PMCID: PMC6080553 DOI: 10.1186/s12964-018-0255-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022] Open
Abstract
Background The Rab27 family of small GTPases promotes the progression of breast cancer, melanoma, and other human cancers. In this review, we discuss the role of Rab27 GTPases in cancer progression and the potential applications of these targets in cancer treatment. Main body Elevated expression of Rab27 GTPases is associated with poor prognosis and cancer metastasis. Moreover, these GTPases govern a variety of oncogenic functions, including cell proliferation, cell motility, and chemosensitivity. In addition, small GTPases promote tumor growth and metastasis by enhancing exosome secretion, which alters intracellular microRNA levels, signaling molecule expression, and the tumor microenvironment. Conclusion Rab27 GTPases may have applications as prognostic markers and therapeutic targets in cancer treatment.
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Affiliation(s)
- Zhihong Li
- Department of Orthopaedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Rui Fang
- Department of Orthopaedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jia Fang
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shasha He
- Department of Oncology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
| | - Tang Liu
- Department of Orthopaedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
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28
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Zhou W, De Iuliis GN, Dun MD, Nixon B. Characteristics of the Epididymal Luminal Environment Responsible for Sperm Maturation and Storage. Front Endocrinol (Lausanne) 2018; 9:59. [PMID: 29541061 PMCID: PMC5835514 DOI: 10.3389/fendo.2018.00059] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The testicular spermatozoa of all mammalian species are considered functionally immature owing to their inability to swim in a progressive manner and engage in productive interactions with the cumulus-oocyte complex. The ability to express these key functional attributes develops progressively during the cells' descent through the epididymis, a highly specialized ductal system that forms an integral part of the male reproductive tract. The functional maturation of the spermatozoon is achieved via continuous interactions with the epididymal luminal microenvironment and remarkably, occurs in the complete absence of de novo gene transcription or protein translation. Compositional analysis of the luminal fluids collected from the epididymis of a variety of species has revealed the complexity of this milieu, with a diversity of inorganic ions, proteins, and small non-coding RNA transcripts having been identified to date. Notably, both the quantitative and qualitative profile of each of these different luminal elements display substantial segment-to-segment variation, which in turn contribute to the regionalized functionality of this long tubule. Thus, spermatozoa acquire functional maturity in the proximal segments before being stored in a quiescent state in the distal segment in preparation for ejaculation. Such marked division of labor is achieved via the combined secretory and absorptive activity of the epithelial cells lining each segment. Here, we review our current understanding of the molecular mechanisms that exert influence over the unique intraluminal environment of the epididymis, with a particular focus on vesicle-dependent mechanisms that facilitate intercellular communication between the epididymal soma and maturing sperm cell population.
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Affiliation(s)
- Wei Zhou
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Geoffry N. De Iuliis
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Matthew D. Dun
- Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
- Cancer Research Program, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, NSW, Australia
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
- *Correspondence: Brett Nixon,
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29
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Gomi H, Osawa H, Uno R, Yasui T, Hosaka M, Torii S, Tsukise A. Canine Salivary Glands: Analysis of Rab and SNARE Protein Expression and SNARE Complex Formation With Diverse Tissue Properties. J Histochem Cytochem 2017; 65:637-653. [PMID: 28914590 DOI: 10.1369/0022155417732527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The comparative structure and expression of salivary components and vesicular transport proteins in the canine major salivary glands were investigated. Histochemical analysis revealed that the morphology of the five major salivary glands-parotid, submandibular, polystomatic sublingual, monostomatic sublingual, and zygomatic glands-was greatly diverse. Immunoblot analysis revealed that expression levels of α-amylase and antimicrobial proteins, such as lysozyme, lactoperoxidase, and lactoferrin, differed among the different glands. Similarly, Rab proteins (Rab3d, Rab11a, Rab11b, Rab27a, and Rab27b) and soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins VAMP4, VAMP8, syntaxin-2, syntaxin-3, syntaxin-4, and syntaxin-6 were expressed at various levels in individual glands. mmunohistochemistry of Rab3d, Rab11b, Rab27b, VAMP4, VAMP8, syntaxin-4, and syntaxin-6 revealed their predominant expression in serous acinar cells, demilunes, and ductal cells. The VAMP4/syntaxin-6 SNARE complex, which is thought to be involved in the maturation of secretory granules in the Golgi field, was found more predominantly in the monostomatic sublingual gland than in the parotid gland. These results suggest that protein expression profiles in canine salivary glands differ among individual glands and reflect the properties of their specialized functions.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Hiromi Osawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Rie Uno
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
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30
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Yang X, Ye X, Sun L, Gao F, Li Y, Ji X, Wang X, Feng Y, Wang X. Downregulation of serum RAB27B confers improved prognosis and is associated with hepatocellular carcinoma progression through PI3K-AKT-P21 signaling. Oncotarget 2017; 8:61118-61132. [PMID: 28977851 PMCID: PMC5617411 DOI: 10.18632/oncotarget.18010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/25/2017] [Indexed: 12/11/2022] Open
Abstract
Previous study revealed that elevated expression of RAB27B in tissues is correlated with hepatocellular carcinoma (HCC) progression; however, the mechanisms involved in promoting HCC development are still unclear. Moreover, HCC tissues are not readily obtained during routine diagnosis. Therefore, to further explore its potential value in early diagnosis, we examined RAB27B expression in patient sera. First, the correlation between serum RAB27B expression and survival, as well as TNM and Barcelona Clinic Liver Cancer stages, were evaluated in patients with HCC. Second, lentiviral vector plasmids carrying interference sequences and plasmids harboring the complete open reading frame of RAB27B were designed to knockdown or overexpress RAB27B in BEL7402 or HuH-7 cells to determine its biological function. Compared with healthy controls and patients with chronic hepatitis B infection, serum RAB27B was significantly increased in patients with HCC. After down-regulating expression of RAB27B, the proliferation of BEL7402 cells was remarkably inhibited both in vitro and in vivo. Additionally, activation of the PI3K/AKT pathway was significantly diminished. Moreover, cell cycle progression of the knockdown cells was notably arrested in the G1/S phase, and upregulation of p21 contributed to this effect. Restoration experiments to recover RAB27B expression revealed opposing results. These findings indicated RAB27B might regulate cell cycle through the PI3K/AKT/p21 pathway by releasing cytokines via exocytosis, thereby modulating the proliferation of HCC cells. RAB27B could potentially be a valuable serum biomarker for the early diagnosis of, and a therapeutic target in, HCC.
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Affiliation(s)
- Xue Yang
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xieqiong Ye
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Le Sun
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Fangyuan Gao
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Yuxin Li
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xiaomin Ji
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xuejiang Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China.,Beijing Key Laboratory for Cancer Invasion and Metastasis Research, Capital Medical University, Beijing, China
| | - Ying Feng
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xianbo Wang
- Center of Integrative Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China
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31
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Abstract
Neurons are highly polarized cells that exhibit one of the more complex morphology and function. Neuronal intracellular trafficking plays a key role in dictating the directionality and specificity of vesicle formation, transport and fusion, allowing the transmission of information in sophisticate cellular network. Thus, the integrity of protein trafficking and spatial organization is especially important in neuronal cells. RAB proteins, small monomeric GTPases belonging to the RAS superfamily, spatially and temporally orchestrate specific vesicular trafficking steps. In this review we summarise the known roles of RAB GTPases involved in the maintenance of neuronal vesicular trafficking in the central nervous system. In particular, we discriminate the axonal pre-synaptic trafficking and dendritic post-synaptic trafficking, to better underlie how a correct orchestration of vesicle movement is necessary to maintain neuronal polarity and then, to permit an accurate architecture and functionality of synaptic activity.
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Affiliation(s)
- Maria Lidia Mignogna
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
| | - Patrizia D'Adamo
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
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32
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Shen Y, Mao H, Huang M, Chen L, Chen J, Cai Z, Wang Y, Xu N. Long Noncoding RNA and mRNA Expression Profiles in the Thyroid Gland of Two Phenotypically Extreme Pig Breeds Using Ribo-Zero RNA Sequencing. Genes (Basel) 2016; 7:genes7070034. [PMID: 27409639 PMCID: PMC4962004 DOI: 10.3390/genes7070034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/24/2016] [Accepted: 07/05/2016] [Indexed: 11/16/2022] Open
Abstract
The thyroid gland is an important endocrine organ modulating development, growth, and metabolism, mainly by controlling the synthesis and secretion of thyroid hormones (THs). However, little is known about the pig thyroid transcriptome. Long non-coding RNAs (lncRNAs) regulate gene expression and play critical roles in many cellular processes. Yorkshire pigs have a higher growth rate but lower fat deposition than that of Jinhua pigs, and thus, these species are ideal models for studying growth and lipid metabolism. This study revealed higher levels of THs in the serum of Yorkshire pigs than in the serum of Jinhua pigs. By using Ribo-zero RNA sequencing—which can capture both polyA and non-polyA transcripts—the thyroid transcriptome of both breeds were analyzed and 22,435 known mRNAs were found to be expressed in the pig thyroid. In addition, 1189 novel mRNAs and 1018 candidate lncRNA transcripts were detected. Multiple TH-synthesis-related genes were identified among the 455 differentially-expressed known mRNAs, 37 novel mRNAs, and 52 lncRNA transcripts. Bioinformatics analysis revealed that differentially-expressed genes were enriched in the microtubule-based process, which contributes to THs secretion. Moreover, integrating analysis predicted 13 potential lncRNA-mRNA gene pairs. These data expanded the repertoire of porcine lncRNAs and mRNAs and contribute to understanding the possible molecular mechanisms involved in animal growth and lipid metabolism.
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Affiliation(s)
- Yifei Shen
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
| | - Haiguang Mao
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
| | - Minjie Huang
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
| | - Lixing Chen
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
| | - Jiucheng Chen
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
| | - Zhaowei Cai
- Laboratory of Animal Research Center, Zhenjiang Chinese Medical University, Hangzhou 310053, China.
| | - Ying Wang
- College of Mechanics, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Ningying Xu
- College of Animal Science, Zhejiang University, Hangzhou 310058, China.
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Higashio H, Satoh YI, Saino T. Mast cell degranulation is negatively regulated by the Munc13-4-binding small-guanosine triphosphatase Rab37. Sci Rep 2016; 6:22539. [PMID: 26931073 PMCID: PMC4773767 DOI: 10.1038/srep22539] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 02/17/2016] [Indexed: 02/07/2023] Open
Abstract
Mast cell degranulation is regulated by the small guanosine triphosphatases (GTPases) Rab27a and Rab27b, which have distinct and opposing roles: Rab27b acts as a positive regulator through its effector protein Munc13-4, a non-neuronal isoform of the vesicle-priming Munc13 family of proteins, whereas Rab27a acts as a negative regulator through its effector protein melanophilin, by maintaining integrity of cortical filamentous actin (F-actin), a barrier to degranulation. Here we investigated the role of Rab37, one of the Rab GTPases assumed to be implicated in regulated secretion during mast cell degranulation. Using the RBL-2H3 mast cell line, we detected Rab37 on the secretory granules and found that antigen-induced degranulation was extensively increased by either knockdown of Rab37 or overexpression of a dominant-active Rab37 mutant. This hypersecretion phenotype in the Rab37-knockdown cells was suppressed by simultaneous knockdown of Rab27a and Rab27b or of Munc13-4, but not by disruption of cortical F-actin. We further found that Rab37 interacted with Munc13-4 in a GTP-independent manner and formed a Rab27-Munc13-4-Rab37 complex. These results suggest that Rab37 is a Munc13-4-binding protein that inhibits mast cell degranulation through its effector protein, by counteracting the vesicle-priming activity of the Rab27-Munc13-4 system.
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Affiliation(s)
- Hironori Higashio
- Department of Chemistry, Center for Liberal Arts and Sciences, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Yoh-ichi Satoh
- Division of Cell Biology, Department of Anatomy, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan.,Department of Medical Education, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Tomoyuki Saino
- Division of Cell Biology, Department of Anatomy, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
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Davila J, Laws MJ, Kannan A, Li Q, Taylor RN, Bagchi MK, Bagchi IC. Rac1 Regulates Endometrial Secretory Function to Control Placental Development. PLoS Genet 2015; 11:e1005458. [PMID: 26305333 PMCID: PMC4549291 DOI: 10.1371/journal.pgen.1005458] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/21/2015] [Indexed: 01/14/2023] Open
Abstract
During placenta development, a succession of complex molecular and cellular interactions between the maternal endometrium and the developing embryo ensures reproductive success. The precise mechanisms regulating this maternal-fetal crosstalk remain unknown. Our study revealed that the expression of Rac1, a member of the Rho family of GTPases, is markedly elevated in mouse decidua on days 7 and 8 of gestation. To investigate its function in the uterus, we created mice bearing a conditional deletion of the Rac1 gene in uterine stromal cells. Ablation of Rac1 did not affect the formation of the decidua but led to fetal loss in mid gestation accompanied by extensive hemorrhage. To gain insights into the molecular pathways affected by the loss of Rac1, we performed gene expression profiling which revealed that Rac1 signaling regulates the expression of Rab27b, another GTPase that plays a key role in targeting vesicular trafficking. Consequently, the Rac1-null decidual cells failed to secrete vascular endothelial growth factor A, which is a critical regulator of decidual angiogenesis, and insulin-like growth factor binding protein 4, which regulates the bioavailability of insulin-like growth factors that promote proliferation and differentiation of trophoblast cell lineages in the ectoplacental cone. The lack of secretion of these key factors by Rac1-null decidua gave rise to impaired angiogenesis and dysregulated proliferation of trophoblast cells, which in turn results in overexpansion of the trophoblast giant cell lineage and disorganized placenta development. Further experiments revealed that RAC1, the human ortholog of Rac1, regulates the secretory activity of human endometrial stromal cells during decidualization, supporting the concept that this signaling G protein plays a central and conserved role in controlling endometrial secretory function. This study provides unique insights into the molecular mechanisms regulating endometrial secretions that mediate stromal-endothelial and stromal-trophoblast crosstalk critical for placenta development and establishment of pregnancy. During early pregnancy, a succession of molecular interactions between the uterus and the developing embryo ensures reproductive success. Although it is conceivable that signaling cues originating in the uterus impact on the developing embryo at the time of placenta establishment, the precise mechanisms regulating the maternal-fetal crosstalk remain unknown. Impaired uterine functions during early pregnancy are likely to contribute to abnormal embryo development and various diseases of pregnancy, such as recurrent miscarriage, preeclampsia, and intrauterine growth restriction. This study provides insights into the molecular mechanisms by which Rac1, a signaling molecule expressed in the decidua, controls uterine secretions that mediate maternal-fetal communication critical for placental development and establishment of pregnancy.
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Affiliation(s)
- Juanmahel Davila
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Mary J. Laws
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Athilakshmi Kannan
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Quanxi Li
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Robert N. Taylor
- Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Milan K. Bagchi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail: (MKB); (ICB)
| | - Indrani C. Bagchi
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail: (MKB); (ICB)
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Reichhart N, Markowski M, Ishiyama S, Wagner A, Crespo-Garcia S, Schorb T, Ramalho JS, Milenkovic VM, Föckler R, Seabra MC, Strauß O. Rab27a GTPase modulates L-type Ca2+ channel function via interaction with the II-III linker of CaV1.3 subunit. Cell Signal 2015; 27:2231-40. [PMID: 26235199 DOI: 10.1016/j.cellsig.2015.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022]
Abstract
In a variety of cells, secretory processes require the activation of both Rab27a and L-type channels of the Ca(V)1.3 subtype. In the retinal pigment epithelium (RPE), Rab27a and Ca(V)1.3 channels regulate growth-factor secretion towards its basolateral side. Analysis of murine retina sections revealed a co-localization of both Rab27a and Ca(V)1.3 at the basolateral membrane of the RPE. Heterologously expressed Ca(V)1.3/β3/α2δ1 channels showed negatively shifted voltage-dependence and decreased current density of about 70% when co-expressed with Rab27a. However, co-localization analysis using α(5)β(1) integrin as a membrane marker revealed that Rab27a co-expression reduced the surface expression of Ca(V)1.3 only about 10%. Physical binding of heterologously expressed Rab27a with Ca(V)1.3 channels was shown by co-localization in immunocytochemistry as well as co-immunoprecipitation which was abolished after deletion of a MyRIP-homologous amino acid sequence at the II-III linker of the Ca(V)1.3 subunit. Rab27a over-expression in ARPE-19 cells positively shifted the voltage dependence, decreased current density of endogenous Ca(V)1.3 channels and reduced VEGF-A secretion. We show the first evidence of a direct functional modulation of an ion channel by Rab27a suggesting a new mechanism of Rab and ion channel interaction in the control of VEGF-A secretion in the RPE.
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Affiliation(s)
- Nadine Reichhart
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Magdalena Markowski
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Shimpei Ishiyama
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Andrea Wagner
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Sergio Crespo-Garcia
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Talitha Schorb
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - José S Ramalho
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Vladimir M Milenkovic
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Department of Psychiatry and Psychotherapy, Molecular Neuroscience, University of Regensburg, Germany
| | - Renate Föckler
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Miguel C Seabra
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Olaf Strauß
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany.
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Gomi H, Morikawa S, Shinmura N, Moki H, Yasui T, Tsukise A, Torii S, Watanabe T, Maeda Y, Hosaka M. Expression of Secretogranin III in Chicken Endocrine Cells: Its Relevance to the Secretory Granule Properties of Peptide Prohormone Processing and Bioactive Amine Content. J Histochem Cytochem 2015; 63:350-66. [PMID: 25673289 PMCID: PMC4409946 DOI: 10.1369/0022155415575032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/05/2015] [Indexed: 01/27/2023] Open
Abstract
The expression of secretogranin III (SgIII) in chicken endocrine cells has not been investigated. There is limited data available for the immunohistochemical localization of SgIII in the brain, pituitary, and pancreatic islets of humans and rodents. In the present study, we used immunoblotting to reveal the similarities between the expression patterns of SgIII in the common endocrine glands of chickens and rats. The protein-protein interactions between SgIII and chromogranin A (CgA) mediate the sorting of CgA/prohormone core aggregates to the secretory granule membrane. We examined these interactions using co-immunoprecipitation in chicken endocrine tissues. Using immunohistochemistry, we also examined the expression of SgIII in a wide range of chicken endocrine glands and gastrointestinal endocrine cells (GECs). SgIII was expressed in the pituitary, pineal, adrenal (medullary parts), parathyroid, and ultimobranchial glands, but not in the thyroid gland. It was also expressed in GECs of the stomach (proventriculus and gizzard), small and large intestines, and pancreatic islet cells. These SgIII-expressing cells co-expressed serotonin, somatostatin, gastric inhibitory polypeptide, glucagon-like peptide-1, glucagon, or insulin. These results suggest that SgIII is expressed in the endocrine cells that secrete peptide hormones, which mature via the intragranular enzymatic processing of prohormones and physiologically active amines in chickens.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Satomi Morikawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Naoki Shinmura
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Hiroaki Moki
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan (ST)
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical College, Asahikawa, Japan (TW)
| | - Yoshinori Maeda
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
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Liu L, Mellerio JE, Martinez AE, McMillan JR, Aristodemou S, Parsons M, McGrath JA. Mutations in EXPH5 result in autosomal recessive inherited skin fragility. Br J Dermatol 2015; 170:196-9. [PMID: 24443915 DOI: 10.1111/bjd.12723] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2013] [Indexed: 12/15/2022]
Abstract
Several different genes have been implicated in the pathophysiology of inherited blistering skin diseases. Recently, autosomal recessive loss-of-function mutations in EXPH5 (encoding exophilin-5, also known as Slac2-b, a protein involved in intracellular vesicle transport) were identified in a new mechanobullous disease resembling a form of epidermolysis bullosa simplex (EBS). Here, we searched for mutations in EXPH5 in a 4-year-old white boy with EBS in whom initial Sanger sequencing of known genes implicated in intraepidermal skin fragility failed to identify pathogenic mutations. Transmission electron microscopy of rubbed nonlesional patient skin revealed disruption of keratinocytes in the lower epidermis with cytolysis and acantholysis, keratin filament clumping and prominent perinuclear cytoplasmic vesicles, and provided the clue to the candidate gene pathology. Sanger sequencing of genomic DNA showed compound heterozygosity for two new mutations in EXPH5, c.1947dupC (p.Pro649fsPro*11) and c.2249C>A (p.Ser750*). Immunofluorescence microscopy of patient skin showed a complete absence of exophilin-5 labelling. This case represents the third pedigree with EXPH5 mutations resulting in inherited skin fragility. The clinical and molecular data expand genotype-phenotype correlation in this new form of EBS and demonstrate the important role of exophilin-5 in keratinocyte cell biology.
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Affiliation(s)
- L Liu
- The Robin Eady National Diagnostic Epidermolysis Bullosa Laboratory, GSTS Pathology, St Thomas' Hospital, London, U.K
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38
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Pavlos NJ, Jahn R. Distinct yet overlapping roles of Rab GTPases on synaptic vesicles. Small GTPases 2014; 2:77-81. [PMID: 21776405 DOI: 10.4161/sgtp.2.2.15201] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 02/17/2011] [Indexed: 11/19/2022] Open
Abstract
Exo-endocytotic cycling of synaptic vesicles (SVs) is one of the most intensely studied membrane trafficking pathways. It is governed by sets of conserved proteins including Rab GTPases. Long considered to define the identity and composition of a subcellular organelle, it has become increasingly evident that multiple Rabs co-exist on intracellular compartments, each contributing to its membrane organization and specialised function. Indeed, we have recently demonstrated that at least 11 distinct Rab proteins co-exist on highly purified SVs. These include Rabs involved in exocytosis (Rab3a/b/c and Rab27b) and intermediates of SV recycling such as early endosomes (Rab4, Rab5, Rab10, Rab11b and Rab14). Interestingly, we found that while two of these proteins, namely Rab3a and Rab27b, exhibited differential cycling dynamics on SV membranes; they played complementary roles during Ca(2+)-triggered neurotransmitter release. The implications of these findings in the SV trafficking cycle are discussed.
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Affiliation(s)
- Nathan J Pavlos
- Department of Neurobiology; Max-Planck Institute for Biophysical Chemistry; Göttingen, Germany
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Prognostic value of Rab27B nuclear expression in gastrointestinal stromal tumors. DISEASE MARKERS 2014; 2014:942181. [PMID: 25382899 PMCID: PMC4213986 DOI: 10.1155/2014/942181] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 09/22/2014] [Indexed: 12/31/2022]
Abstract
Rab proteins of the endocytosis and exocytosis pathways both play critical roles in cancer progression, and Rab27B has a significant relationship with several types of human cancer. However, the association between Rab27B expression and clinical features to determine its clinicopathological significance in gastrointestinal tumor (GIST) has not been investigated. To examine the expression of Rab27B in GIST and investigate the association between its expression and patient prognosis, immunohistochemistry analysis with tissue microarray was used to evaluate expression of Rab27B in 162 patients with GIST. The relationship between Rab27B expression and patient prognosis was analyzed. High nuclear staining of Rab27B was detected in 88 of 162 (54.32%) GIST tissues. Positive staining of Rab27B was significantly associated with tumor size (P = 0.006), mitotic index (P = 0.013), Armed Forces Institute of Pathology Miettinen risk classification (P = 0.002), and tumor grade (P = 0.021). Kaplan-Meier survival curves showed that GIST patients with low Rab27B nuclear expression (P = 0.038) and mitotic index <5 per 50 high-power fields (P = 0.029) had a more favorable prognosis. These findings indicate that Rab27B nuclear expression is correlated with several clinicopathological features of GIST patients, and it may serve as an unfavorable prognostic marker.
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40
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Cazares VA, Subramani A, Saldate JJ, Hoerauf W, Stuenkel EL. Distinct actions of Rab3 and Rab27 GTPases on late stages of exocytosis of insulin. Traffic 2014; 15:997-1015. [PMID: 24909540 DOI: 10.1111/tra.12182] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/04/2014] [Accepted: 06/04/2014] [Indexed: 12/16/2022]
Abstract
Rab GTPases associated with insulin-containing secretory granules (SGs) are key in targeting, docking and assembly of molecular complexes governing pancreatic β-cell exocytosis. Four Rab3 isoforms along with Rab27A are associated with insulin granules, yet elucidation of the distinct roles of these Rab families on exocytosis remains unclear. To define specific actions of these Rab families we employ Rab3GAP and/or EPI64A GTPase-activating protein overexpression in β-cells from wild-type or Ashen mice to selectively transit the entire Rab3 family or Rab27A to a GDP-bound state. Ashen mice carry a spontaneous mutation that eliminates Rab27A expression. Using membrane capacitance measurements we find that GTP/GDP nucleotide cycling of Rab27A is essential for generation of the functionally defined immediately releasable pool (IRP) and central to regulating the size of the readily releasable pool (RRP). By comparison, nucleotide cycling of Rab3 GTPases, but not of Rab27A, is essential for a kinetically rapid filling of the RRP with SGs. Aside from these distinct functions, Rab3 and Rab27A GTPases demonstrate considerable functional overlap in building the readily releasable granule pool. Hence, while Rab3 and Rab27A cooperate to generate release-ready SGs in β-cells, they also direct unique kinetic and functional properties of the exocytotic pathway.
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Affiliation(s)
- Victor A Cazares
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
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Gómez-Lázaro M, Rinn C, Aroso M, Amado F, Schrader M. Proteomic analysis of zymogen granules. Expert Rev Proteomics 2014; 7:735-47. [DOI: 10.1586/epr.10.31] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Berg-Larsen A, Landsverk OJB, Progida C, Gregers TF, Bakke O. Differential regulation of Rab GTPase expression in monocyte-derived dendritic cells upon lipopolysaccharide activation: a correlation to maturation-dependent functional properties. PLoS One 2013; 8:e73538. [PMID: 24039975 PMCID: PMC3764041 DOI: 10.1371/journal.pone.0073538] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/21/2013] [Indexed: 12/25/2022] Open
Abstract
The regulation of Rab expression to modulate cellular function has recently been proposed. Dendritic cells are a prototypic example of cells that drastically alter their function in response to environmental cues by reducing endocytosis, secreting cytokines, changing surface protein repertoires and altering morphology and migration. This is not a binary event, but is subject to fluctuations through the activation process, termed maturation. Consequently, DCs transiently increase endocytosis and production of major histocompatibility complex class II molecules, and secrete inflammatory cytokines in infected tissues before migrating to secondary lymph nodes and releasing T cell polarizing factors. All these cellular processes rely on intracellular membrane transport, which is regulated by Rab family GTPases and their diverse effectors. Here we examine how the Rabs likely to be involved in these functions are regulated throughout DC maturation. We find that Rab expression is altered upon lipopolysaccharide-induced activation, and discuss how this correlates to the reported functions of these cells during maturation.
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Affiliation(s)
- Axel Berg-Larsen
- Centre for Immune Regulation, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ole J. B. Landsverk
- Centre for Immune Regulation, Department of Biosciences, University of Oslo, Oslo, Norway
- * E-mail:
| | - Cinzia Progida
- Centre for Immune Regulation, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Tone F. Gregers
- Centre for Immune Regulation, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Oddmund Bakke
- Centre for Immune Regulation, Department of Biosciences, University of Oslo, Oslo, Norway
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Fukuda M. Rab27 effectors, pleiotropic regulators in secretory pathways. Traffic 2013; 14:949-63. [PMID: 23678941 DOI: 10.1111/tra.12083] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/13/2013] [Accepted: 05/16/2013] [Indexed: 12/18/2022]
Abstract
Rab27, a member of the small GTPase Rab family, is widely conserved in metazoan, and two Rab27 isoforms, Rab27A and Rab27B, are present in vertebrates. Rab27A was the first Rab protein whose dysfunction was found to cause a human hereditary disease, type 2 Griscelli syndrome, which is characterized by silvery hair and immunodeficiency. The discovery in the 21st century of three distinct types of mammalian Rab27A effectors [synaptotagmin-like protein (Slp), Slp homologue lacking C2 domains (Slac2), and Munc13-4] that specifically bind active Rab27A has greatly accelerated our understanding not only of the molecular mechanisms of Rab27A-mediated membrane traffic (e.g. melanosome transport and regulated secretion) but of the symptoms of Griscelli syndrome patients at the molecular level. Because Rab27B is widely expressed in various tissues together with Rab27A and has been found to have the ability to bind all of the Rab27A effectors that have been tested, Rab27A and Rab27B were initially thought to function redundantly by sharing common Rab27 effectors. However, recent evidence has indicated that by interacting with different Rab27 effectors Rab27A and Rab27B play different roles in special types of secretion (e.g. exosome secretion and mast cell secretion) even within the same cell type. In this review article, I describe the current state of our understanding of the functions of Rab27 effectors in secretory pathways.
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Affiliation(s)
- Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
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44
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Upregulation of the Rab27a-dependent trafficking and secretory mechanisms improves lysosomal transport, alleviates endoplasmic reticulum stress, and reduces lysosome overload in cystinosis. Mol Cell Biol 2013; 33:2950-62. [PMID: 23716592 DOI: 10.1128/mcb.00417-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cystinosis is a lysosomal storage disorder caused by the accumulation of the amino acid cystine due to genetic defects in the CTNS gene, which encodes cystinosin, the lysosomal cystine transporter. Although many cellular dysfunctions have been described in cystinosis, the mechanisms leading to these defects are not well understood. Here, we show that increased lysosomal overload induced by accumulated cystine leads to cellular abnormalities, including vesicular transport defects and increased endoplasmic reticulum (ER) stress, and that correction of lysosomal transport improves cellular function in cystinosis. We found that Rab27a was expressed in proximal tubular cells (PTCs) and partially colocalized with the lysosomal marker LAMP-1. The expression of Rab27a but not other small GTPases, including Rab3 and Rab7, was downregulated in kidneys from Ctns-/- mice and in human PTCs from cystinotic patients. Using total internal reflection fluorescence microscopy, we found that lysosomal transport is impaired in Ctns-/- cells. Ctns-/- cells showed significant ER expansion and a marked increase in the unfolded protein response-induced chaperones Grp78 and Grp94. Upregulation of the Rab27a-dependent vesicular trafficking mechanisms rescued the defective lysosomal transport phenotype and reduced ER stress in cystinotic cells. Importantly, reconstitution of lysosomal transport mediated by Rab27a led to decreased lysosomal overload, manifested as reduced cystine cellular content. Our data suggest that upregulation of the Rab27a-dependent lysosomal trafficking and secretory pathways contributes to the correction of some of the cellular defects induced by lysosomal overload in cystinosis, including ER stress.
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Hou Y, Chen X, Tolmachova T, Ernst SA, Williams JA. EPI64B acts as a GTPase-activating protein for Rab27B in pancreatic acinar cells. J Biol Chem 2013; 288:19548-57. [PMID: 23671284 DOI: 10.1074/jbc.m113.472134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The small GTPase Rab27B localizes to the zymogen granule membranes and plays an important role in regulating protein secretion by pancreatic acinar cells, as does Rab3D. A common guanine nucleotide exchange factor (GEF) for Rab3 and Rab27 has been reported; however, the GTPase-activating protein (GAP) specific for Rab27B has not been identified. In this study, the expression in mouse pancreatic acini of two candidate Tre-2/Bub2/Cdc16 (TBC) domain-containing proteins, EPI64 (TBC1D10A) and EPI64B (TBC1D10B), was first demonstrated. Their GAP activity on digestive enzyme secretion was examined by adenovirus-mediated overexpression of EPI64 and EPI64B in isolated pancreatic acini. EPI64B almost completely abolished the GTP-bound form of Rab27B, without affecting GTP-Rab3D. Overexpression of EPI64B also enhanced amylase release. This enhanced release was independent of Rab27A, but dependent on Rab27B, as shown using acini from genetically modified mice. EPI64 had a mild effect on both GTP-Rab27B and amylase release. Co-overexpression of EPI64B with Rab27B can reverse the inhibitory effect of Rab27B on amylase release. Mutations that block the GAP activity decreased the inhibitory effect of EPI64B on the GTP-bound state of Rab27B and abolished the enhancing effect of EPI64B on the amylase release. These data suggest that EPI64B can serve as a potential physiological GAP for Rab27B and thereby participate in the regulation of exocytosis in pancreatic acinar cells.
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Affiliation(s)
- Yanan Hou
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Catz SD. Regulation of vesicular trafficking and leukocyte function by Rab27 GTPases and their effectors. J Leukoc Biol 2013; 94:613-22. [PMID: 23378593 DOI: 10.1189/jlb.1112600] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Rab27 family of GTPases regulates the efficiency and specificity of exocytosis in hematopoietic cells, including neutrophils, CTLs, NK cells, and mast cells. However, the mechanisms regulated by Rab27 GTPases are cell-specific, as they depend on the differential expression and function of particular effector molecules that are recruited by the GTPases. In addition, Rab27 GTPases participate in multiple steps of the regulation of the secretory process, including priming, tethering, docking, and fusion through sequential interaction with multiple effector molecules. Finally, recent reports suggest that Rab27 GTPases and their effectors regulate vesicular trafficking mechanisms other than exocytosis, including endocytosis and phagocytosis. This review focuses on the latest discoveries on the function of Rab27 GTPases and their effectors Munc13-4 and Slp1 in neutrophil function comparatively to their functions in other leukocytes.
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Affiliation(s)
- Sergio Daniel Catz
- 1.The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA. ; Twitter: http://www.scripps.edu/catz/
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Singh RK, Mizuno K, Wasmeier C, Wavre-Shapton ST, Recchi C, Catz SD, Futter C, Tolmachova T, Hume AN, Seabra MC. Distinct and opposing roles for Rab27a/Mlph/MyoVa and Rab27b/Munc13-4 in mast cell secretion. FEBS J 2013; 280:892-903. [PMID: 23281710 DOI: 10.1111/febs.12081] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 10/31/2012] [Accepted: 11/26/2012] [Indexed: 11/29/2022]
Abstract
Mediator release from mast cells is a critical step in allergic and inflammatory disease. However, the processes regulating the latter stages of granule release are yet to be fully understood. Rab27 small GTPases regulate release of secretory lysosomes in a variety of cells, including mast cell granules. In the present study, using murine bone marrow-derived mast cells (BMMC) from Rab27-deficient mutant mice, we found that, in contrast to Rab27b, Rab27a primarily plays an inhibitory role in regulating degranulation. Immunofluorescence analysis revealed that resting Rab27a-deficient (ashen) BMMCs display abnormal cortical F-actin distribution. Actin disassembly prior to IgE cross-linking increased wild-type BMMC secretion to ashen levels, suggesting that changes in the integrity of cortical F-actin underlie the ashen phenotype. Comparison of the secretory impairment of Rab27b knockout and Rab27a/b double knockout BMMCs highlighted a secondary positive role for Rab27a in enhancing degranulation. Rab27 is known to interact with actin via its effectors melanophilin (Mlph) and myosin Va (MyoVa) in other cell types. To better understand the differing roles of Rab27 proteins, we analysed the secretory phenotype of BMMCs derived from mice lacking Rab27 effector proteins. These experiments revealed that the phenotype of BMMCs deficient in Mlph (leaden) and BMMCs deficient in MyoVa (dilute) resembles the hyper-secretion of ashen BMMCs, while Munc13-4-deficient (jinx) BMMCs phenocopy the Rab27b knockout and double Rab27a/b knockout secretory impairment. We conclude that Rab27a and Rab27b regulate distinct steps in the BMMC degranulation pathway, with Rab27a/Mlph/MyoVa regulating cortical actin stability upstream of Rab27a/b/Munc13-4-dependent granule exocytosis.
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Affiliation(s)
- Rajesh K Singh
- Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK
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Khan AR. Oligomerization of rab/effector complexes in the regulation of vesicle trafficking. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:579-614. [PMID: 23663983 DOI: 10.1016/b978-0-12-386931-9.00021-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rabs comprise the largest member of the Ras superfamily of small GTPases with over 60 proteins in mammals and 11 proteins in yeast. Like all small GTPases, Rabs oscillate between an inactive GDP-bound conformation and an active GTP-bound state that is tethered to lipid membranes via a C-terminal prenylation site on conserved cysteine residues. In their active state, Rabs regulate various aspects of membrane trafficking, including vesicle formation, transport, docking, and fusion. The critical element of biological activity is the recruitment of cytosolic effector proteins to specific endomembranes by active Rabs. The importance of Rabs in cellular processes is apparent from their links to genetic disorders, immunodeficiency, cancer, and pathogen invasion. During the last decade, numerous structures of complexes have shed light on the molecular basis for Rab/effector specificity and their topological organization on subcellular membranes. Here, I review the known structures of Rab/effector complexes and their modes of oligomerization. This is followed by a brief discussion on the thermodynamics of effector recruitment, which has not been documented sufficiently in previous reviews. A summary of diseases associated with Rab/effector trafficking pathways concludes this chapter.
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Affiliation(s)
- Amir R Khan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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Germline Mutation in EXPH5 Implicates the Rab27B Effector Protein Slac2-b in Inherited Skin Fragility. Am J Hum Genet 2012. [PMID: 23176819 DOI: 10.1016/j.ajhg.2012.10.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Rab GTPase Rab27B and one of its effector proteins, Slac2-b (also known as EXPH5, exophilin-5), have putative roles in intracellular vesicle trafficking but their relevance to human disease is not known. By using whole-exome sequencing, we identified a homozygous frameshift mutation in EXPH5 in three siblings with inherited skin fragility born to consanguineous Iraqi parents. All three individuals harbor the mutation c.5786delC (p.Pro1929Leufs(∗)8) in EXPH5, which truncates the 1,989 amino acid Slac2-b protein by 52 residues. The clinical features comprised generalized scale-crusts and occasional blisters, mostly induced by trauma, as well as mild diffuse pigmentary mottling on the trunk and proximal limbs. There was no increased bleeding tendency, no neurologic abnormalities, and no increased incidence of infection. Analysis of an affected person's skin showed loss of Slac2-b immunostaining (C-terminal antibody), disruption of keratinocyte adhesion within the lower epidermis, and an increased number of perinuclear vesicles. A role for Slac2-b in keratinocyte biology was supported by findings of cytoskeletal disruption (mainly keratin intermediate filaments) and decreased keratinocyte adhesion in both keratinocytes from an affected subject and after shRNA knockdown of Slac2-b in normal keratinocytes. Slac2-b was also shown to colocalize with Rab27B and β4 integrin to early adhesion initiation sites in spreading normal keratinocytes. Collectively, our findings identify an unexpected role for Slac2-b in inherited skin fragility and expand the clinical spectrum of human disorders of GTPase effector proteins.
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Wang H, Ishizaki R, Xu J, Kasai K, Kobayashi E, Gomi H, Izumi T. The Rab27a effector exophilin7 promotes fusion of secretory granules that have not been docked to the plasma membrane. Mol Biol Cell 2012; 24:319-30. [PMID: 23223571 PMCID: PMC3564536 DOI: 10.1091/mbc.e12-04-0265] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent microscopic recordings in living cells demonstrated that granules without prior stable docking to the plasma membrane can efficiently undergo exocytosis, although the molecular mechanism is unknown. The present report is the first to identify exophilin7 as a molecule that functions in the exocytosis of undocked granules. Granuphilin, an effector of the small GTPase Rab27a, mediates the stable attachment (docking) of insulin granules to the plasma membrane and inhibits subsequent fusion of docked granules, possibly through interaction with a fusion-inhibitory Munc18-1/syntaxin complex. However, phenotypes of insulin exocytosis differ considerably between Rab27a- and granuphilin-deficient pancreatic β cells, suggesting that other Rab27a effectors function in those cells. We found that one of the putative Rab27a effector family proteins, exophilin7/JFC1/Slp1, is expressed in β cells; however, unlike granuphilin, exophilin7 overexpressed in the β-cell line MIN6 failed to show granule-docking or fusion-inhibitory activity. Furthermore, exophilin7 has no affinities to either Munc18-1 or Munc18-1–interacting syntaxin-1a, in contrast to granuphilin. Although β cells of exophilin7-knockout mice show no apparent abnormalities in intracellular distribution or in ordinary glucose-induced exocytosis of insulin granules, they do show impaired fusion in response to some stronger stimuli, specifically from granules that have not been docked to the plasma membrane. Exophilin7 appears to mediate the fusion of undocked granules through the affinity of its C2A domain toward the plasma membrane phospholipids. These findings indicate that the two Rab27a effectors, granuphilin and exophilin7, differentially regulate the exocytosis of either stably or minimally docked granules, respectively.
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Affiliation(s)
- Hao Wang
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
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