1
|
Huang W, Lin M, Rikihisa Y. Rab27a via its effector JFC1 localizes to Anaplasma inclusions and promotes Anaplasma proliferation in leukocytes. Microbes Infect 2023:105278. [PMID: 38110148 DOI: 10.1016/j.micinf.2023.105278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/20/2023]
Abstract
Anaplasma phagocytophilum is an obligatory intracellular bacterium that causes tick-borne zoonosis called human granulocytic anaplasmosis. Mechanisms by which Anaplasma replicates inside of the membrane-bound compartment called "inclusion" in neutrophils are incompletely understood. A small GTPase Rab27a is found in the secretory granules and multivesicular endosomes. In this study we found Rab27a-containing granules were localized to Anaplasma inclusions in guanine nucleotide-dependent manner, and constitutively active Rab27a enhanced Anaplasma infection and dominant-negative Rab27a inhibited Anaplasma infection. Rab27a effector, JFC1 is known to mediate docking/fusion of Rab27a-bearing granules for exocytosis in leukocytes. shRNA stable knockdown of Rab27a or JFC1 inhibited Anaplasma infection in HL-60 cells. Similar to Rab27a, both endogenous and transfected JFC1 were localized to Anaplasma inclusions by immunostaining or live cell imaging. The JFC1 C2A domain that binds 3'-phosphoinositides, was sufficient and required for JFC1 and Rab27a localization to Anaplasma inclusions which were enriched with phosphatidylinositol 3-phosphate. Nexinhib20, the small molecule inhibitor specific to Rab27a and JFC1 binding, inhibited Anaplasma infection. Taken together, these results imply elevated phosphatidylinositol 3-phosphate in the inclusion membrane recruits JFC1 to mediate Rab27a-bearing granules/vesicles to dock/fuse with Anaplasma inclusions, the lumen of which is topologically equivalent to the exterior of the cell to benefit Anaplasma proliferation.
Collapse
Affiliation(s)
- Weiyan Huang
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Mingqun Lin
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA.
| |
Collapse
|
2
|
Meijuan C, Meng X, Fang L, Qian W. Synaptotagmin-like protein 1 is a potential diagnostic and prognostic biomarker in endometrial cancer based on bioinformatics and experiments. J Ovarian Res 2023; 16:16. [PMID: 36653850 PMCID: PMC9850549 DOI: 10.1186/s13048-023-01097-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/11/2023] [Indexed: 01/20/2023] Open
Abstract
Endometrial cancer (EC) is one of the most common gynecologic malignancies. Identification of potential EC biomarkers is essential to improve the prognosis and development of therapies against EC. Synaptotagmin-like protein 1 (SYTL1), as a small GTPase Rab27 effector, mainly plays a role in vesicle trafficking and cytotoxic granule exocytosis in lymphocytes. However the role of SYTL1 in EC remains uncertain. We performed a comprehensive assessment of the relationship between SYTL1 and patient diagnosis and prognosis by analysis of EC patients' data from TCGA. We employed the LinkedOmics and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database to analyze the biological function of SYTL1 in EC. In addition, the correlation between SYTL1 expression and its DNA methylation was performed by using cBioportal, UALCAN, TCGA Wanderer and MethSurv databases. We further assessed the link between SYTL1 and tumor-infiltrating immune cells by using gene set variation analysis (GSVA).Results We found that SYTL1 was highly expressed in EC patients and cell lines. And increased expression of SYTL1 was associated with age, clinical stage, histological type, histological grade and good overall survival (OS).SYTL1 DNA methylation is negatively associated with SYTL1 expression and UCEC patients' OS. SYTL1 expression is closely correlated with immune infiltration. Furthermore, we carried out in vitro experiments to verify the results of bioinformatic analysis.Conclusion Our results demonstrated that the elevation of SYTL1 expression is associated with good OS and SYTL1 might be a potential diagnostic and prognostic marker in EC.
Collapse
Affiliation(s)
- Cai Meijuan
- grid.452402.50000 0004 1808 3430Department of Clinical Laboratory, Qilu Hospital of Shandong University, No.107 Wenhua West Road, 250013 Jinan, Shandong China ,grid.452402.50000 0004 1808 3430Department of Clinical Laboratory, Qilu Hospital of Shandong University (Qingdao), Qingdao, Shandong China
| | - Xu Meng
- grid.452402.50000 0004 1808 3430Department of Clinical Laboratory, Qilu Hospital of Shandong University (Qingdao), Qingdao, Shandong China
| | - Liu Fang
- Department of Pathology, Qingdao Chengyang People’s Hospital, No.758 Hefei Road, Shandong 266035 Qingdao, China
| | - Wang Qian
- grid.452402.50000 0004 1808 3430Department of Clinical Laboratory, Qilu Hospital of Shandong University, No.107 Wenhua West Road, 250013 Jinan, Shandong China ,grid.452402.50000 0004 1808 3430Department of Clinical Laboratory, Qilu Hospital of Shandong University (Qingdao), Qingdao, Shandong China
| |
Collapse
|
3
|
Overlapping Machinery in Lysosome-Related Organelle Trafficking: A Lesson from Rare Multisystem Disorders. Cells 2022; 11:cells11223702. [PMID: 36429129 PMCID: PMC9688865 DOI: 10.3390/cells11223702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/08/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022] Open
Abstract
Lysosome-related organelles (LROs) are a group of functionally diverse, cell type-specific compartments. LROs include melanosomes, alpha and dense granules, lytic granules, lamellar bodies and other compartments with distinct morphologies and functions allowing specialised and unique functions of their host cells. The formation, maturation and secretion of specific LROs are compromised in a number of hereditary rare multisystem disorders, including Hermansky-Pudlak syndromes, Griscelli syndrome and the Arthrogryposis, Renal dysfunction and Cholestasis syndrome. Each of these disorders impacts the function of several LROs, resulting in a variety of clinical features affecting systems such as immunity, neurophysiology and pigmentation. This has demonstrated the close relationship between LROs and led to the identification of conserved components required for LRO biogenesis and function. Here, we discuss aspects of this conserved machinery among LROs in relation to the heritable multisystem disorders they associate with, and present our current understanding of how dysfunctions in the proteins affected in the disease impact the formation, motility and ultimate secretion of LROs. Moreover, we have analysed the expression of the members of the CHEVI complex affected in Arthrogryposis, Renal dysfunction and Cholestasis syndrome, in different cell types, by collecting single cell RNA expression data from the human protein atlas. We propose a hypothesis describing how transcriptional regulation could constitute a mechanism that regulates the pleiotropic functions of proteins and their interacting partners in different LROs.
Collapse
|
4
|
Huang D, Zeng Y, Deng HY, Fu BD, Ke Y, Luo JY, Yu JC, Yu ST. SYTL5 Promotes Papillary Thyroid Carcinoma Progression by Enhancing Activation of the NF-κB Signaling Pathway. Endocrinology 2022; 164:6828016. [PMID: 36378561 DOI: 10.1210/endocr/bqac187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 11/17/2022]
Abstract
The function and mechanism of SYTL5 in papillary thyroid carcinoma (PTC) are still unclear. In this research, we found that SYTL5 was significantly overexpressed in PTC tissues compared with normal thyroid tissues. SYTL5 downregulation significantly weakened the proliferative, migratory, and invasive abilities of PTC cells. In addition, upregulated SYTL5 could promote cancer progression by activating the NF-κB signaling pathway. RAC1b expression is positively associated with SYTL5, and overexpressed RAC1b abrogated the antitumor effect after SYTL5 inhibition. In conclusion, our findings identify the oncogenic role of SYTL5 in PTC by activation of the NF-κB signaling pathway, thus facilitating PTC development and progression.
Collapse
Affiliation(s)
- Da Huang
- Department of Thyroid surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Ying Zeng
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330038, China
| | - Han-Yue Deng
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330038, China
| | - Bi-Dong Fu
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330038, China
| | - Yun Ke
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330038, China
| | - Jing-Yi Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Ji-Chun Yu
- Department of Thyroid surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Shi-Tong Yu
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong 510150, China
| |
Collapse
|
5
|
Catz SD, McLeish KR. Therapeutic targeting of neutrophil exocytosis. J Leukoc Biol 2020; 107:393-408. [PMID: 31990103 PMCID: PMC7044074 DOI: 10.1002/jlb.3ri0120-645r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 12/11/2022] Open
Abstract
Dysregulation of neutrophil activation causes disease in humans. Neither global inhibition of neutrophil functions nor neutrophil depletion provides safe and/or effective therapeutic approaches. The role of neutrophil granule exocytosis in multiple steps leading to recruitment and cell injury led each of our laboratories to develop molecular inhibitors that interfere with specific molecular regulators of secretion. This review summarizes neutrophil granule formation and contents, the role granule cargo plays in neutrophil functional responses and neutrophil-mediated diseases, and the mechanisms of granule release that provide the rationale for development of our exocytosis inhibitors. We present evidence for the inhibition of granule exocytosis in vitro and in vivo by those inhibitors and summarize animal data indicating that inhibition of neutrophil exocytosis is a viable therapeutic strategy.
Collapse
Affiliation(s)
- Sergio D. Catz
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA
| | - Kenneth R. McLeish
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY
| |
Collapse
|
6
|
Ramadass M, Johnson JL, Marki A, Zhang J, Wolf D, Kiosses WB, Pestonjamasp K, Ley K, Catz SD. The trafficking protein JFC1 regulates Rac1-GTP localization at the uropod controlling neutrophil chemotaxis and in vivo migration. J Leukoc Biol 2019; 105:1209-1224. [PMID: 30748033 DOI: 10.1002/jlb.1vma0818-320r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/09/2019] [Accepted: 01/22/2019] [Indexed: 01/01/2023] Open
Abstract
Neutrophil chemotaxis is essential in responses to infection and underlies inflammation. In neutrophils, the small GTPase Rac1 has discrete functions at both the leading edge and in the retraction of the trailing structure at the cell's rear (uropod), but how Rac1 is regulated at the uropod is unknown. Here, we identified a mechanism mediated by the trafficking protein synaptotagmin-like 1 (SYTL1 or JFC1) that controls Rac1-GTP recycling from the uropod and promotes directional migration of neutrophils. JFC1-null neutrophils displayed defective polarization and impaired directional migration to N-formyl-methionine-leucyl-phenylalanine in vitro, but chemoattractant-induced actin remodeling, calcium signaling and Erk activation were normal in these cells. Defective chemotaxis was not explained by impaired azurophilic granule exocytosis associated with JFC1 deficiency. Mechanistically, we show that active Rac1 localizes at dynamic vesicles where endogenous JFC1 colocalizes with Rac1-GTP. Super-resolution microscopy (STORM) analysis shows adjacent distribution of JFC1 and Rac1-GTP, which increases upon activation. JFC1 interacts with Rac1-GTP in a Rab27a-independent manner to regulate Rac1-GTP trafficking. JFC1-null cells exhibited Rac1-GTP accumulation at the uropod and increased tail length, and Rac1-GTP uropod accumulation was recapitulated by inhibition of ROCK or by interference with microtubule remodeling. In vivo, neutrophil dynamic studies in mixed bone marrow chimeric mice show that JFC1-/- neutrophils are unable to move directionally toward the source of the chemoattractant, supporting the notion that JFC1 deficiency results in defective neutrophil migration. Our results suggest that defective Rac1-GTP recycling from the uropod affects directionality and highlight JFC1-mediated Rac1 trafficking as a potential target to regulate chemotaxis in inflammation and immunity.
Collapse
Affiliation(s)
- Mahalakshmi Ramadass
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Jennifer L Johnson
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Alex Marki
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Jinzhong Zhang
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Dennis Wolf
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - William B Kiosses
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Kersi Pestonjamasp
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Klaus Ley
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Sergio D Catz
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| |
Collapse
|
7
|
Positive associations between galectin-3 and PSA levels in prostate cancer patients: a prospective clinical study-I. Oncotarget 2018; 7:82266-82272. [PMID: 27741512 PMCID: PMC5347690 DOI: 10.18632/oncotarget.12619] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/20/2016] [Indexed: 01/28/2023] Open
Abstract
Galectin-3 (Gal-3), an oncogenic pro-inflammatory protein, has been suggested as a possible complementary diagnostic candidate to prostate specific antigen (PSA) blood test for prostate cancer patients. The presence of the proteins in the circulation (biomarkers) may elicit an intrinsic humoral immune reaction by generating autoantibodies, which consequently could alter the detection levels. Here, we report the associations of the two prostate cancer biomarkers, Gal-3 and PSA in patients at different clinical states of prostate cancer while taking into account the autoantibody levels. A blind, prospective, single institution, pilot study was conducted. A total of 95 men were classified into 5 groups: healthy controls (Group1), newly diagnosed patients (Group2), no recurrence after local therapy (Group3), rising PSA after local therapy (Group4), and metastatic patients (Group5). Gal-3 and PSA level were divided by their respective autoantibodies, which yielded relative PSA and relative Gal-3 levels. After the adjustments, Spearman's rank correlations and linear regression modeling revealed the positive associations between relative Gal-3 and relative PSA levels among all 95 men combined (rho = 0.446, P < 0.0001; fitted slope 0.448, P < 0.0001), in Group2 (rho = 0.616, P = 0.0050; fitted slope 0.438, P =0.0011), and Group3 (rho = 0.484, P = 0.0360; fitted slope 0.470, P = 0.0187). The data show positive associations of relative Gal-3 and relative PSA levels in prostate cancer patients, notably at early clinical time course. Allowing for the influence of autoantibodies, Gal-3 level might be considered as a potential biomarker since it is positively associated with PSA level.
Collapse
|
8
|
Worst TS, Meyer Y, Gottschalt M, Weis CA, von Hardenberg J, Frank C, Steidler A, Michel MS, Erben P. RAB27A, RAB27B and VPS36 are downregulated in advanced prostate cancer and show functional relevance in prostate cancer cells. Int J Oncol 2017; 50:920-932. [PMID: 28197629 DOI: 10.3892/ijo.2017.3872] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/05/2016] [Indexed: 11/06/2022] Open
Abstract
Paracrine and long-range signaling via extracellular vesicles, such as exosomes and microvesicles, is deemed crucial for tumorigenesis, invasion and spread of solid tumors. The ESCRT machinery (endosomal sorting complexes required for transport) and Rab-proteins act as key players in vesicular trafficking and secretion. Yet, their role in prostate cancer (PCa) is unknown. Therefore, this study aimed to elucidate the relevance of these components in PCa. In silico reanalysis of genes with known involvement in vesicular trafficking and secretion in an existing microarray dataset revealed low expression of RAB27A, RAB27B and VPS36 to be predictive for reduced BCR-free survival in patients with localized PCa (p=0.033, 0.025 and 0.005). In the same microarray dataset underexpression of RAB27A, RAB27B and VPS36 was seen in distant metastases (p<0.001; p=0.003; p<0.001). This was consistent in two further microarray datasets. qRT-PCR-validation in two independent cohorts of PCa specimens (n=90) showed low expression of VPS36 in PCa tissue (p=0.023), especially in castration-resistant tumors (p=0.002). In all five datasets there were significant correlations between the expression of at least two of the candidates. Upon knockdown of VPS36 an increase of RAB27A and RAB27B expression, but not vice versa, was observed in both prostate and breast cancer cells (PC3, MDA-MB‑231). In PC3 cell knockdown of RAB27B and VPS36 dramatically reduced colony formation (-52.2%, p<0.001; -71.1%, p<0.001) and, controversial to reports in other tumor entities, increased the release of extracellular particles (+25.3%, p=0.014; +45.6%, p<0.001). Taken together RAB27A, RAB27B and VPS36 are frequently underexpressed in advanced PCa and are inversely correlated with PCa outcome. There seems to be a close relationship in the expression of RAB27A, RAB27B and VPS36, with RAB27A and RAB27B being dependent on VPS36. Changes in colony formation and particle release upon RNAi indicate an involvement in paracrine cell-cell communication.
Collapse
Affiliation(s)
- Thomas Stefan Worst
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Yannic Meyer
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Maria Gottschalt
- Institute of Pathology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Cleo-Aron Weis
- Institute of Pathology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Jost von Hardenberg
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Christine Frank
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Annette Steidler
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Maurice Stephan Michel
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| | - Philipp Erben
- Department of Urology, Mannheim Medical Center, University of Heidelberg, D-68167 Mannheim, Germany
| |
Collapse
|
9
|
Reyes-Hernández OD, Vega L, Jiménez-Ríos MA, Martínez-Cervera PF, Lugo-García JA, Hernández-Cadena L, Ostrosky-Wegman P, Orozco L, Elizondo G. The PXR rs7643645 polymorphism is associated with the risk of higher prostate-specific antigen levels in prostate cancer patients. PLoS One 2014; 9:e99974. [PMID: 24924803 PMCID: PMC4055777 DOI: 10.1371/journal.pone.0099974] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 05/20/2014] [Indexed: 01/23/2023] Open
Abstract
Levels of enzymes that determine testosterone catabolism such as CYP3A4 have been associated with prostate cancer (PCa) risk. Although some studies have related CYP3A4*1B allele, a gene polymorphism that modifies CYP3A4 expression level, with PCa risk, others have failed, suggesting that additional genetic variants may be involved. Expression of CYP3A4 is largely due to the activation of Pregnane X Receptor (PXR). Particularly, rs2472677 and rs7643645 PXR polymorphisms modify CYP3A4 expression levels. To evaluate whether PXR-HNF3β/T (rs2472677), PXR-HNF4/G (rs7643645), and CYP3A4*1B (rs2740574) polymorphisms are associated with PCa a case control-study was performed. The multiple testing analysis showed that the PXR-HNF4/G polymorphism was associated with higher levels of prostate-specific antigen (PSA) in patients with PCa (OR = 3.99, p = 0.03). This association was stronger in patients diagnosed at the age of 65 years or older (OR = 10.8, p = 0.006). Although the CYP3A4*1B/*1B genotype was overrepresented in PCa patients, no differences were observed in the frequency of this and PXR-HNF3β/T alleles between controls and cases. Moreover, no significant association was found between these polymorphisms and PSA, Gleason grade, or tumor lymph node metastasis.
Collapse
Affiliation(s)
| | - Libia Vega
- Departamento de Toxicología, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, México, D.F., México
| | | | | | - Juan A. Lugo-García
- Laboratorio de Genética y Diagnóstico Molecular, Hospital Juárez de México, México, D.F., México
| | | | - Patricia Ostrosky-Wegman
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., México
| | - Lorena Orozco
- Laboratorio de Inmunogenómica y Enfermedades Metabólicas, Instituto Nacional de Medicina Genómica, México, D.F., México
| | - Guillermo Elizondo
- Departamento de Biología Celular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, México, D.F., México
- * E-mail:
| |
Collapse
|
10
|
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: 153] [Impact Index Per Article: 13.9] [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.
Collapse
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.
| |
Collapse
|
11
|
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.
Collapse
|
12
|
Muniyan S, Chaturvedi NK, Dwyer JG, LaGrange CA, Chaney WG, Lin MF. Human prostatic acid phosphatase: structure, function and regulation. Int J Mol Sci 2013; 14:10438-64. [PMID: 23698773 PMCID: PMC3676848 DOI: 10.3390/ijms140510438] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/16/2022] Open
Abstract
Human prostatic acid phosphatase (PAcP) is a 100 kDa glycoprotein composed of two subunits. Recent advances demonstrate that cellular PAcP (cPAcP) functions as a protein tyrosine phosphatase by dephosphorylating ErbB-2/Neu/HER-2 at the phosphotyrosine residues in prostate cancer (PCa) cells, which results in reduced tumorigenicity. Further, the interaction of cPAcP and ErbB-2 regulates androgen sensitivity of PCa cells. Knockdown of cPAcP expression allows androgen-sensitive PCa cells to develop the castration-resistant phenotype, where cells proliferate under an androgen-reduced condition. Thus, cPAcP has a significant influence on PCa cell growth. Interestingly, promoter analysis suggests that PAcP expression can be regulated by NF-κB, via a novel binding sequence in an androgen-independent manner. Further understanding of PAcP function and regulation of expression will have a significant impact on understanding PCa progression and therapy.
Collapse
Affiliation(s)
- Sakthivel Muniyan
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mails: (S.M.); (N.K.C.); (W.G.C.)
| | - Nagendra K. Chaturvedi
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mails: (S.M.); (N.K.C.); (W.G.C.)
| | - Jennifer G. Dwyer
- College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mail:
| | - Chad A. LaGrange
- Department of Surgery/Urology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mail:
| | - William G. Chaney
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mails: (S.M.); (N.K.C.); (W.G.C.)
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Ming-Fong Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mails: (S.M.); (N.K.C.); (W.G.C.)
- Department of Surgery/Urology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; E-Mail:
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
- College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| |
Collapse
|
13
|
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.
Collapse
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/
| |
Collapse
|
14
|
Human Prostatic Acid Phosphatase in Prostate Carcinogenesis. Prostate Cancer 2013. [DOI: 10.1007/978-1-4614-6828-8_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
15
|
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: 27] [Impact Index Per Article: 2.3] [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.
Collapse
Affiliation(s)
- Hao Wang
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | | | | | | | | | | | | |
Collapse
|
16
|
Zografou S, Basagiannis D, Papafotika A, Shirakawa R, Horiuchi H, Auerbach D, Fukuda M, Christoforidis S. A complete Rab screening reveals novel insights in Weibel-Palade body exocytosis. J Cell Sci 2012; 125:4780-90. [PMID: 22899725 DOI: 10.1242/jcs.104174] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Weibel-Palade bodies (WPBs) are endothelial-cell-specific organelles that, upon fusion with the plasma membrane, release cargo molecules that are essential in blood vessel abnormalities, such as thrombosis and inflammation, as well as in angiogenesis. Despite the importance of WPBs, the basic mechanisms that mediate their secretion are only poorly understood. Rab GTPases play fundamental role in the trafficking of intracellular organelles. Yet, the only known WPB-associated Rabs are Rab27a and Rab3d. To determine the full spectrum of WPB-associated Rabs we performed a complete Rab screening by analysing the localisation of all Rabs in WPBs and their involvement in the secretory process in endothelial cells. Apart from Rab3 and Rab27, we identified three additional Rabs, Rab15 (a previously reported endocytic Rab), Rab33 and Rab37, on the WPB limiting membrane. A knockdown approach using siRNAs showed that among these five WPB Rabs only Rab3, Rab27 and Rab15 are required for exocytosis. Intriguingly, we found that Rab15 cooperates with Rab27a in WPB secretion. Furthermore, a specific effector of Rab27, Munc13-4, appears to be also an effector of Rab15 and is required for WPB exocytosis. These data indicate that WPB secretion requires the coordinated function of a specific group of Rabs and that, among them, Rab27a and Rab15, as well as their effector Munc13-4, cooperate to drive exocytosis.
Collapse
Affiliation(s)
- Sofia Zografou
- Institute of Molecular Biology and Biotechnology, Department of Ioannina/Foundation for Research and Technology Hellas, Ioannina, Greece
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Johnson JL, Monfregola J, Napolitano G, Kiosses WB, Catz SD. Vesicular trafficking through cortical actin during exocytosis is regulated by the Rab27a effector JFC1/Slp1 and the RhoA-GTPase-activating protein Gem-interacting protein. Mol Biol Cell 2012; 23:1902-16. [PMID: 22438581 PMCID: PMC3350554 DOI: 10.1091/mbc.e11-12-1001] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mechanism of cytoskeleton remodeling during exocytosis is not well defined. A combination of vesicular dynamics and functional studies shows that the Rab27a effector JFC1 and the RhoA-GTPase–activating protein Gem-interacting protein are necessary for RhoA regulation, actin depolymerization, and vesicular transport through the actin cortex during exocytosis. Cytoskeleton remodeling is important for the regulation of vesicular transport associated with exocytosis, but a direct association between granular secretory proteins and actin-remodeling molecules has not been shown, and this mechanism remains obscure. Using a proteomic approach, we identified the RhoA-GTPase–activating protein Gem-interacting protein (GMIP) as a factor that associates with the Rab27a effector JFC1 and modulates vesicular transport and exocytosis. GMIP down-regulation induced RhoA activation and actin polymerization. Importantly, GMIP-down-regulated cells showed impaired vesicular transport and exocytosis, while inhibition of the RhoA-signaling pathway induced actin depolymerization and facilitated exocytosis. We show that RhoA activity polarizes around JFC1-containing secretory granules, suggesting that it may control directionality of granule movement. Using quantitative live-cell microscopy, we show that JFC1-containing secretory organelles move in areas near the plasma membrane deprived of polymerized actin and that dynamic vesicles maintain an actin-free environment in their surroundings. Supporting a role for JFC1 in RhoA inactivation and actin remodeling during exocytosis, JFC1 knockout neutrophils showed increased RhoA activity, and azurophilic granules were unable to traverse cortical actin in cells lacking JFC1. We propose that during exocytosis, actin depolymerization commences near the secretory organelle, not the plasma membrane, and that secretory granules use a JFC1- and GMIP-dependent molecular mechanism to traverse cortical actin.
Collapse
Affiliation(s)
- Jennifer L Johnson
- Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | | | | | | | | |
Collapse
|
18
|
Mitra S, Cheng KW, Mills GB. Rab GTPases implicated in inherited and acquired disorders. Semin Cell Dev Biol 2010; 22:57-68. [PMID: 21147240 DOI: 10.1016/j.semcdb.2010.12.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 12/06/2010] [Accepted: 12/06/2010] [Indexed: 01/05/2023]
Abstract
The endocytotic machinery imports, transports and exports receptors and associated molecules between the plasma membrane and various cytoplasmic chambers resulting in selective recycling, degradation, or secretion of molecules and signaling complexes. Trafficking of receptors, growth factors, nutrients, cytokines, integrins as well as pathogens dictates the kinetics and magnitude of signal transduction cascades. Understandably, alterations in the 'fate' of such cargo complexes have profound physiologic and pathophysiologic implications. Rab GTPases regulate endocytosis by decorating intracellular vesicles and targeting these vesicles along with their cargoes to appropriate subcellular compartments. In the last decade, the number of genetic diseases driven by germline mutations in Rab GTPases or their interacting proteins, has increased and there is growing evidence of aberrant Rab GTPase function in acquired pathophysiologies such as immune deficiency, infection, obesity, diabetes and cancer.
Collapse
Affiliation(s)
- Shreya Mitra
- Department of Systems Biology, The University of Texas, MD Anderson Cancer Center, Houston, TX 77054-1942, USA.
| | | | | |
Collapse
|
19
|
Nicotera TM, Schuster DP, Bourhim M, Chadha K, Klaich G, Corral DA. Regulation of PSA secretion and survival signaling by calcium-independent phopholipase A(2)beta in prostate cancer cells. Prostate 2009; 69:1270-80. [PMID: 19475654 DOI: 10.1002/pros.20968] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Serum prostate specific antigen (PSA) levels in prostate cancer patients serve as a useful biomarker for diagnosing and monitoring prostate cancer. Recently, secreted PSA has been characterized as an autocrine survival factor through activation of Akt and induction of AR. In the normal prostate, PSA is secreted in the lumen of prostatic ducts to lyse proteins in the seminal coagulum. METHODS However, the mechanism for constitutive PSA secretion from benign prostate and its transport across the prostate-blood barrier into serum are unknown. Regulation of peptide secretion by iPLA(2)-beta has been reported in non-prostatic tissue and in prostate tissue iPLA(2)-beta is reported to be under androgen regulation. We investigated whether iPLA(2) plays a role for in PSA secretion by comparing iPLA(2) activity and expression in normal prostate epithelial RWPE-1 cells and in LNCaP prostate cancer cells. Expression of the two active iPLA(2)-beta mRNA splice variants, LH-iPLA(2) and SH-iPLA(2), were increased and the inhibitory ankyrin-iPLA(2) isoform was markedly reduced in LNCaP cells as compared to normal prostate epithelial RWPE-1 cells. RESULTS These changes are consistent with a higher enzymatic activity in LNCaP cells. The iPLA(2)-beta-specific inhibitor BEL inhibited PSA secretion and induced apoptosis in LNCaP cells. iPLA(2) knockdown using SiRNA inhibited PSA secretion, downregulated AR and induced apoptosis. Exogenous PSA suppressed BEL-induced apoptosis and neutralizing anti-PSA antibody blocked the survival effect of PSA. CONCLUSIONS These data indicate that iPLA(2)-beta participates in regulating PSA secretion and supports the concept that secreted PSA provides an autocrine survival function in LNCaP cells.
Collapse
Affiliation(s)
- Thomas M Nicotera
- Department of Cancer Prevention & Population Sciences, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
| | | | | | | | | | | |
Collapse
|
20
|
Synaptotagmin-like protein 1 interacts with the GTPase-activating protein Rap1GAP2 and regulates dense granule secretion in platelets. Blood 2009; 114:1396-404. [PMID: 19528539 DOI: 10.1182/blood-2008-05-155234] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The small guanine-nucleotide-binding protein Rap1 plays a key role in platelet aggregation and hemostasis, and we recently identified Rap1GAP2 as the only GTPase-activating protein of Rap1 in platelets. In search of Rap1GAP2-associated proteins, we performed yeast-2-hybrid screening and found synaptotagmin-like protein 1 (Slp1) as a new binding partner. We confirmed the interaction of Rap1GAP2 and Slp1 in transfected COS-1 and HeLa cells and at endogenous level in human platelets. Mapping studies showed that Rap1GAP2 binds through amino acids T524-K525-X-T527 within its C-terminus to the C2A domain of Slp1. Slp1 contains a Rab27-binding domain, and we demonstrate that Rap1GAP2, Slp1, and Rab27 form a trimeric complex in transfected cells and in platelets. Purified Slp1 dose-dependently decreased dense granule secretion in streptolysin-O-permeabilized platelets stimulated with calcium or guanosine 5'-O-[gamma-thio] triphosphate. The isolated C2A domain of Slp1 had a stimulatory effect on granule secretion and reversed the inhibitory effect of full-length Slp1. Purified Rap1GAP2 augmented dense granule secretion of permeabilized platelets, whereas deletion of the Slp1-binding TKXT motif abolished the effect of Rap1GAP2. We conclude that Slp1 inhibits dense granule secretion in platelets and that Rap1GAP2 modulates secretion by binding to Slp1.
Collapse
|
21
|
Wright PK, May FEB, Darby S, Saif R, Lennard TWJ, Westley BR. Estrogen regulates vesicle trafficking gene expression in EFF-3, EFM-19 and MCF-7 breast cancer cells. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2009; 2:463-475. [PMID: 19294005 PMCID: PMC2655148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/26/2009] [Indexed: 05/27/2023]
Abstract
Estrogens are critical mediators of breast tumorigenesis. This occurs via the action of estrogens on the estrogen receptor (ER), which regulates the transcriptome of breast cancer cells. Despite the long history of the search for estrogen-regulated genes in breast cancer, knowledge of the E2-regulated transcriptome and its effects is incomplete. We used Affymetrix GeneChips to profile the effects of estradiol on the expression of genes in EFF-3, EFM-19 and MCF-7 cells. In addition to many well-characterized estrogen-regulated genes, this identified a novel group of genes that have roles in vesicle trafficking, including exocytosis. Recent evidence in the literature supports a role for vesicle trafficking in tumorigenesis. We focused on five genes (SYTL5, RAB27B, SNX24, GALNT4 and SLC12A2/NKCC1/BSC2) and confirmed their estrogen-regulation using quantitative real-time PCR (qPCR). qPCR also demonstrated that these five genes were expressed in invasive breast carcinoma tissue. Immunohistochemistry showed expression of SYTL5 in cells of normal breast ductal epithelium, ductal carcinoma in-situ (DCIS) and invasive breast carcinoma. The results suggest that a significant effect of estrogens is to regulate the expression of genes that affect diverse aspects of vesicle trafficking including exocytosis.
Collapse
Affiliation(s)
- Paul K. Wright
- Northern Institute for Cancer Research, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
- School of Surgical and Reproductive Sciences, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Felicity EB May
- Northern Institute for Cancer Research, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Steve Darby
- Northern Institute for Cancer Research, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Rehan Saif
- Northern Institute for Cancer Research, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
- School of Surgical and Reproductive Sciences, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Tom WJ Lennard
- School of Surgical and Reproductive Sciences, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Bruce R Westley
- Northern Institute for Cancer Research, Medical School, Newcastle UniversityFramlington Place, Newcastle upon Tyne, NE2 4HH, UK
| |
Collapse
|
22
|
Morris MA, Dawson CW, Wei W, O'Neil JD, Stewart SE, Jia J, Bell AI, Young LS, Arrand JR. Epstein–Barr virus-encoded LMP1 induces a hyperproliferative and inflammatory gene expression programme in cultured keratinocytes. J Gen Virol 2008; 89:2806-2820. [DOI: 10.1099/vir.0.2008/003970-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SCC12F cells are a line of keratinocytes that retain the capacity for terminal differentiation in vitro. We showed previously that the Epstein–Barr virus (EBV)-encoded oncogene latent membrane protein 1 (LMP1) altered SCC12F morphology in vitro, downregulated cell–cell-adhesion molecule expression and promoted cell motility. In organotypic raft culture, LMP1-expressing cells failed to stratify and formed poorly organized structures which displayed impaired terminal differentiation. To understand better the mechanism(s) by which LMP1 induces these effects, we generated SCC12F cells in which LMP1 expression is inducible. Following induction, these cells exhibited phenotypic changes similar to those observed previously and allowed us to investigate the effects of LMP1 expression on cellular pathways associated with growth, differentiation and morphology. Using microarrays and a number of confirmatory techniques, we identified sets of differentially expressed genes that are characteristically expressed in inflammatory and hyperproliferative epidermis, including chemokines, cytokines and their receptors, growth factors involved in promoting epithelial cell motility and proliferation and signalling molecules that regulate actin filament reorganization and cell movement. Among the genes whose expression was differentially induced significantly by LMP1, the induction of IL-1β and IL-1α was of particular interest, as many of the LMP1-regulated genes identified are established targets of these cytokines. Our findings suggest that alterations in the IL-1 signalling network may be responsible for many of the changes in host-cell gene expression induced in response to LMP1. Identification of these LMP1-regulated genes helps to define the mechanism(s) by which this oncoprotein influences cellular pathways that regulate terminal differentiation, cell motility and inflammation.
Collapse
Affiliation(s)
- Mhairi A. Morris
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Christopher W. Dawson
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Wenbin Wei
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - John D. O'Neil
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Suzanne E. Stewart
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Junying Jia
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Andrew I. Bell
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - Lawrence S. Young
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| | - John R. Arrand
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TT, UK
| |
Collapse
|
23
|
Brzezinska AA, Johnson JL, Munafo DB, Crozat K, Beutler B, Kiosses WB, Ellis BA, Catz SD. The Rab27a effectors JFC1/Slp1 and Munc13-4 regulate exocytosis of neutrophil granules. Traffic 2008; 9:2151-64. [PMID: 18939952 DOI: 10.1111/j.1600-0854.2008.00838.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Neutrophil granules contain secretory molecules that contribute to the implementation of all neutrophil functions. The molecular components that regulate the exocytosis of neutrophil granules have not been characterized. In this study, using small interfering RNA gene-targeting approaches and granulocytes from genetically modified mice, we characterized the Rab27a effectors JFC1/Slp1 and Munc13-4 as components of the exocytic machinery of granulocytes. Using total internal reflection fluorescence microscopy analysis, we show that Rab27a and JFC1 colocalize in predocked and docked vesicles in granulocytes. Next, we demonstrate that JFC1-downregulated granulocytes have impaired myeloperoxidase secretion. Using immunological interference, we confirm that JFC1 plays an important role in azurophilic granule exocytosis in human neutrophils. Interference with Rab27a but not with JFC1 impaired gelatinase B secretion in neutrophils, suggesting that a different Rab27a effector modulates this process. In similar studies, we confirmed that Munc13-4 regulates gelatinase secretion. Immunofluorescence analysis indicates that Munc13-4 localizes at secretory organelles in neutrophils. Using neutrophils from a Munc13-4-deficient mouse model (Jinx), we demonstrate that Munc13-4 plays a central role in the regulation of exocytosis of various sets of secretory organelles. However, mobilization of CD11b was not affected in Munc13-4-deficient neutrophils, indicating that secretory defects in these cells are limited to a selective group of exocytosable organelles.
Collapse
Affiliation(s)
- Agnieszka A Brzezinska
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Catz SD. Characterization of Rab27a and JFC1 as constituents of the secretory machinery of prostate-specific antigen in prostate carcinoma cells. Methods Enzymol 2008; 438:25-40. [PMID: 18413239 DOI: 10.1016/s0076-6879(07)38003-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PSAP) are produced by prostate carcinoma cells. Their secretion has implications in both prostate cancer diagnosis and progression. The mechanisms involved in PSA and PSAP secretion in response to androgens have remained relatively unknown. The small GTPase Rab27a regulates exocytosis in several tissues. Here, we present methods for the characterization of Rab27a and its effector JFC1/Slp1 as key components of the secretory machinery that regulates exocytosis in prostate carcinoma cells.
Collapse
Affiliation(s)
- Sergio D Catz
- Division of Biochemistry, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| |
Collapse
|
25
|
Martens S, McMahon HT. Mechanisms of membrane fusion: disparate players and common principles. Nat Rev Mol Cell Biol 2008; 9:543-56. [DOI: 10.1038/nrm2417] [Citation(s) in RCA: 524] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
26
|
Saegusa C, Kanno E, Itohara S, Fukuda M. Expression of Rab27B-binding protein Slp1 in pancreatic acinar cells and its involvement in amylase secretion. Arch Biochem Biophys 2008; 475:87-92. [PMID: 18477466 DOI: 10.1016/j.abb.2008.04.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 04/18/2008] [Indexed: 12/16/2022]
Abstract
Slp1 is a putative Rab27 effector protein and implicated in intracellular membrane transport; however, the precise tissue distribution and function of Slp1 protein remain largely unknown. In this study we investigated the tissue distribution of Slp1 in mice and found that Slp1 is abundantly expressed in the pancreas, especially in the apical region of pancreatic acinar cells. Slp1 interacted with Rab27B in vivo and both proteins were co-localized on zymogen granules. Morphological analysis of fasted Slp1 knockout mice showed an increased number of zymogen granules in the pancreatic acinar cells, indicating that Slp1 is part of the machinery of amylase secretion by the exocrine pancreas.
Collapse
Affiliation(s)
- Chika Saegusa
- Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | | |
Collapse
|
27
|
Gackière F, Bidaux G, Delcourt P, Van Coppenolle F, Katsogiannou M, Dewailly E, Bavencoffe A, Van Chuoï-Mariot MT, Mauroy B, Prevarskaya N, Mariot P. CaV3.2 T-type calcium channels are involved in calcium-dependent secretion of neuroendocrine prostate cancer cells. J Biol Chem 2008; 283:10162-73. [PMID: 18230611 DOI: 10.1074/jbc.m707159200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Because prostate cancer is, in its early stages, an androgen-dependent pathology, treatments aiming at decreasing testosterone plasma concentration have been developed for many years now. However, a significant proportion of patients suffer a relapse after a few years of hormone therapy. The androgen-independent stage of prostate cancer has been shown to be associated with the development of neuroendocrine differentiation. We previously demonstrated that neuroendocrine prostate cancer cells derived from LNCaP cells overexpress CaV3.2 T-type voltage-dependent calcium channels. We demonstrate here using prostatic acid phosphatase as a marker of prostate secretion and FM1-43 fluorescence imaging of membrane trafficking that neuroendocrine differentiation is associated with an increase in calcium-dependent secretion which critically relies on CaV3.2 T-type calcium channel activity. In addition, we show that these channels are expressed by neuroendocrine cells in prostate cancer tissues obtained from patients after surgery. We propose that CaV3.2 T-type calcium channel up-regulation may account for the alteration of secretion during prostate cancer development and that these channels, by promoting the secretion of potential mitogenic factors, could participate in the progression of the disease toward an androgen-independent stage.
Collapse
Affiliation(s)
- Florian Gackière
- INSERM U800, Laboratoire de Physiologie Cellulaire, Equipe Labellisée par la Ligue contre le Cancer and Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
Recent discoveries that Rab27a/b and their multiple effectors are involved in the regulated exocytosis of lysosome-related organelles and secretory granules have generated numerous related studies. However, not all of these studies have yielded physiologically relevant data because they were not all performed under physiological conditions. For example, "in vivo interactions" have been claimed without examination of the endogenous complex. In some studies, the only proof of interaction was between exogenously expressed proteins in cultured cells where these proteins are not normally expressed. Because regulated exocytic pathways contain highly differentiated secretory organelles, it is important to analyze the molecular interaction in cells harboring these organelles and the associated molecules. Furthermore, previous overexpression experiments to examine the effect on secretion often failed to compare the level of the exogenous protein with that of the endogenous one. Similarly, some knockdown experiments using small-interfering RNAs have only shown downregulation of the exogenously expressed protein, and not of the endogenous one. Many of the conflicting findings in previous studies may be attributable to these shortcomings. The present study summarizes our knowledge about the roles of Rab27 effectors in regulated exocytic pathways based on physiologically relevant data.
Collapse
Affiliation(s)
- Tetsuro Izumi
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University
| |
Collapse
|
29
|
Maruyama S, Miyajima N, Bohgaki M, Tsukiyama T, Shigemura M, Nonomura K, Hatakeyama S. Ubiquitylation of epsilon-COP by PIRH2 and regulation of the secretion of PSA. Mol Cell Biochem 2007; 307:73-82. [PMID: 17721809 DOI: 10.1007/s11010-007-9586-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2007] [Accepted: 08/10/2007] [Indexed: 02/06/2023]
Abstract
Ubiquitylation appears to be involved in the membrane trafficking system including endocytosis, exocytosis, and ER-to-Golgi transport. We found that PIRH2, which was identified as an interacting protein for androgen receptor or p53, interacts with and ubiquitylates the epsilon-subunit of coatmer complex, epsilon-COP. PIRH2 promotes the ubiquitylation of epsilon-COP in vitro and in vivo and consequently promotes the degradation of epsilon-COP. The interaction between PIRH2 and epsilon-COP is affected by the presence of androgen, and PIRH2 in the presence of androgen promotes ubiquitylation of epsilon-COP in vivo. Furthermore, overexpression of the wild type of PIRH2 in prostate cancer cells causes downregulation of the secretion of prostate-specific antigen (PSA), a secretory protein in prostate epithelial cells and one of diagnostic markers for prostate cancer. Our results indicate that PIRH2 functions as a regulator for COP I complex.
Collapse
Affiliation(s)
- Satoru Maruyama
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | | | | | | | | | | | | |
Collapse
|
30
|
Mizuno K, Tolmachova T, Ushakov DS, Romao M, Åbrink M, Ferenczi MA, Raposo G, Seabra MC. Rab27b regulates mast cell granule dynamics and secretion. Traffic 2007; 8:883-92. [PMID: 17587407 PMCID: PMC2063611 DOI: 10.1111/j.1600-0854.2007.00571.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Rab GTPase family regulates membrane domain organization and vesicular transport pathways. Recent studies indicate that one member of the family, Rab27a, regulates transport of lysosome-related organelles in specialized cells, such as melanosomes and lytic granules. Very little is known about the related isoform, Rab27b. Here we used genetically modified mice to study the involvement of the Rab27 proteins in mast cells, which play key roles in allergic responses. Both Rab27a and Rab27b isoforms are expressed in bone marrow-derived mast cells (BMMC) and localize to secretory granules. Nevertheless, secretory defects as measured by β-hexosaminidase release in vitro and passive cutaneous anaphylaxis in vivo were found only in Rab27b and double Rab27 knockout (KO) mice. Immunofluorescence studies suggest that a subset of Rab27b and double Rab27-deficient BMMCs exhibit mild clustering of granules. Quantitative analysis of live-cell time-lapse imaging revealed that BMMCs derived from double Rab27 KO mice showed almost 10-fold increase in granules exhibiting fast movement (>1.5 μm/s), which could be disrupted by nocodazole. These results suggest that Rab27 proteins, particularly Rab27b, play a crucial role in mast cell degranulation and that their action regulates the transition from microtubule to actin-based motility.
Collapse
Affiliation(s)
- Kouichi Mizuno
- Molecular and Cellular Medicine, National Heart and Lung Institute, Imperial College London SW7 2AZUK
| | - Tanya Tolmachova
- Molecular and Cellular Medicine, National Heart and Lung Institute, Imperial College London SW7 2AZUK
| | - Dmitry S Ushakov
- Biological Nanoscience, National Heart and Lung Institute, Imperial College London SW7 2AZUK
| | - Maryse Romao
- Institut Curie, CNRS UMR144, Structure and Membrane Compartments, 75248 ParisFrance
| | - Magnus Åbrink
- Department of Medical Biochemistry and Microbiology, Uppsala University, 751 05 UppsalaSweden
| | - Michael A Ferenczi
- Biological Nanoscience, National Heart and Lung Institute, Imperial College London SW7 2AZUK
| | - Graça Raposo
- Institut Curie, CNRS UMR144, Structure and Membrane Compartments, 75248 ParisFrance
| | - Miguel C Seabra
- Molecular and Cellular Medicine, National Heart and Lung Institute, Imperial College London SW7 2AZUK
- * Corresponding author: Miguel C. Seabra,
| |
Collapse
|
31
|
Munafó D, Johnson J, Ellis B, Rutschmann S, Beutler B, Catz S. Rab27a is a key component of the secretory machinery of azurophilic granules in granulocytes. Biochem J 2007; 402:229-39. [PMID: 17090228 PMCID: PMC1798439 DOI: 10.1042/bj20060950] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neutrophils kill micro-organisms using microbicidal products that they release into the phagosome or into the extracellular space. The secretory machinery utilized by neutrophils is poorly characterized. We show that the small GTPase Rab27a is an essential component of the secretory machinery of azurophilic granules in granulocytes. Rab27a-deficient mice have impaired secretion of MPO (myeloperoxidase) into the plasma in response to lipopolysaccharide. Cell fractionation analysis revealed that Rab27a and the Rab27a effector protein JFC1/Slp1 (synaptotagmin-like protein 1) are distributed principally in the low-density fraction containing a minor population of MPO-containing granules. By immunofluorescence microscopy, we detected Rab27a and JFC1/Slp1 in a minor subpopulation of MPO-containing granules. Interference with the JFC1/Slp1-Rab27a secretory machinery impaired secretion of MPO in permeabilized neutrophils. The expression of Rab27a was dramatically increased when promyelocytic HL-60 cells were differentiated into granulocytes but not when they were differentiated into monocytes. Down-regulation of Rab27a in HL-60 cells by RNA interference did not affect JFC1/Slp1 expression but significantly decreased the secretion of MPO. Neither Rab27a nor JFC1/Slp1 was integrated into the phagolysosome membrane during phagocytosis. Neutrophils from Rab27a-deficient mice efficiently phagocytose zymosan opsonized particles and deliver MPO to the phagosome. We conclude that Rab27a and JFC1/Slp1 permit MPO release into the surrounding milieu and constitute key components of the secretory machinery of azurophilic granules in granulocytes. Our results suggest that the granules implicated in cargo release towards the surrounding milieu are molecularly and mechanistically different from those involved in their release towards the phagolysosome.
Collapse
Affiliation(s)
- Daniela B. Munafó
- *Department of Molecular and Experimental Medicine, Division of Biochemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla CA, 92037, U.S.A
| | - Jennifer L. Johnson
- *Department of Molecular and Experimental Medicine, Division of Biochemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla CA, 92037, U.S.A
| | - Beverly A. Ellis
- *Department of Molecular and Experimental Medicine, Division of Biochemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla CA, 92037, U.S.A
| | - Sophie Rutschmann
- †Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, U.S.A
| | - Bruce Beutler
- †Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, U.S.A
| | - Sergio D. Catz
- *Department of Molecular and Experimental Medicine, Division of Biochemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla CA, 92037, U.S.A
- To whom correspondence should be addressed (email )
| |
Collapse
|
32
|
Handley MTW, Haynes LP, Burgoyne RD. Differential dynamics of Rab3A and Rab27A on secretory granules. J Cell Sci 2007; 120:973-84. [PMID: 17311845 PMCID: PMC1855981 DOI: 10.1242/jcs.03406] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We have assessed the dynamics of the association of Rab3A and Rab27A with secretory granules at various stages of their life in PC12 cells. Endogenous Rab3A colocalised with the secretory granule marker secretogranin II (SGII) and expressed EGFP-Rab3A and ECFP-Rab27A colocalised with one another. The extent of colocalisation between EGFP-Rab3A or EGFP-Rab27 and SGII increased after longer times post transfection suggesting that these Rab proteins are preferentially recruited to newly synthesised granules. Following the release of immature secretory granules from the trans-Golgi network, Rab3A and Rab27A became associated with the immature granules after a lag period of around 20 minutes. Rab dynamics on granules were analysed in fluorescence recovery after photobleaching (FRAP) experiments. The recovery profile of EGFP-Rab27A was comparable to that of ppANF-EGFP, whereas the recovery profile of EGFP-Rab3A was significantly faster, indicating that Rab3A but not Rab27A might be rapidly exchanged between granules and cytosol. Inhibition of heat-shock protein 90 with 10 muM geldanamycin did not affect the exchange process or regulated exocytosis. Rab dynamics during stimulation with 300 muM ATP were analysed in live cells. Loss of granular ppANF-EGFP fluorescence was seen at the cell periphery after stimulation but only limited changes in EGFP-Rab3A and EGFP-Rab27A fluorescence was observed, indicating that the Rab proteins do not immediately dissociate or disperse on stimulation. The data suggest potentially distinct roles for Rab3A and Rab27A and we suggest that the finding that young secretory granules have a higher capacity for binding Rab3A and Rab27A is functionally important for preferential exocytosis from these granules.
Collapse
Affiliation(s)
- Mark T W Handley
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | | | | |
Collapse
|
33
|
Hattula K, Furuhjelm J, Tikkanen J, Tanhuanpää K, Laakkonen P, Peränen J. Characterization of the Rab8-specific membrane traffic route linked to protrusion formation. J Cell Sci 2006; 119:4866-77. [PMID: 17105768 DOI: 10.1242/jcs.03275] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Rab8 has a drastic effect on cell shape, but the membrane trafficking route it regulates is poorly defined. Here, we show that endogenous and ectopically expressed Rab8 is associated with macropinosomes generated at ruffling membrane domains. These macropinosomes fuse or transform into tubules that move toward the cell center, from where they are recycled back to the leading edge. The biogenesis of these tubules is dependent on actin and microtubular dynamics. Expression of dominant-negative Rab8 mutants or depletion of Rab8 by RNA interference inhibit protrusion formation, but promote cell-cell adhesion and actin stress fiber formation, whereas expression of the constitutively active Rab8-Q67L has the opposite effect. Rab8 localization overlaps with both Rab11 and Arf6, and is functionally linked to Arf6. We also demonstrate that Rab8 activity is needed for the transport of transferrin and the transferrin receptor to the pericentriolar region and to cell protrusions, and that Rab8 controls the traffic of cholera toxin B to the Golgi compartment. Finally, Rab8 colocalizes and binds specifically to a synaptotagmin-like protein (Slp1/JFC1), which is involved in controlling Rab8 membrane dynamics. We propose that Rab8 regulates a membrane-recycling pathway that mediates protrusion formation.
Collapse
Affiliation(s)
- Katarina Hattula
- Institute of Biotechnology, PO Box 56 (Viikinkaari 9), FIN-00014 University of Helsinki, Finland
| | | | | | | | | | | |
Collapse
|
34
|
Fukuda M. Rab27 and its effectors in secretory granule exocytosis: a novel docking machinery composed of a Rab27·effector complex. Biochem Soc Trans 2006; 34:691-5. [PMID: 17052176 DOI: 10.1042/bst0340691] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A small GTPase Rab27 is present on secretory granules in a wide variety of secretory cells and on melanosomes in melanocytes, and it is involved in controlling the trafficking of these organelles through interaction with a cell-type- or tissue-specific Rab27 effector(s). Slps (synaptotagmin-like proteins) and rabphilin contain an N-terminal Rab27-binding domain and C-terminal tandem C2 domains, and some of the Rab27-binding proteins have recently been shown to promote docking of Rab27-bound organelles to the plasma membrane. This mini-review presents a model for how the Rab27·effector complex controls the docking step in the trafficking of Rab27-bound organelles. Our results indicate that Slp2-a, Slp4-a/granuphilin-a and rabphilin are capable of interacting with the plasma membrane directly or indirectly, and thus that these Rab27 effectors form a bridge between Rab27-bound organelles and the plasma membrane.
Collapse
Affiliation(s)
- M Fukuda
- Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| |
Collapse
|
35
|
Abstract
Secretory lysosomes are lysosomes which are capable of undergoing regulated secretion in response to external stimuli. Many cells of the immune system use secretory lysosomes to release proteins involved in their specialised effector mechanisms. Precisely how lysosomal secretion is regulated in each of these cell types is now the study of much research as these mechanisms control the ability of each of these cells to function. Studies on a number of human genetic diseases have identified some key proteins in controlling secretory lysosome release, and now many interacting partners have been identified. The different regulatory components seem to vary from one cell type to another, providing a multitude of ways for fine tuning the release of secretory lysosomes.
Collapse
Affiliation(s)
- Oliver J Holt
- Sir William Dunn School of Pathology, South Parks Rd, Oxford OX1 3RE, UK
| | | | | |
Collapse
|