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Hall BA, Senior KE, Ocampo NT, Samanta D. Coxiella burnetii-containing vacuoles interact with host recycling endosomal proteins Rab11a and Rab35 for vacuolar expansion and bacterial growth. Front Cell Infect Microbiol 2024; 14:1394019. [PMID: 38841112 PMCID: PMC11150555 DOI: 10.3389/fcimb.2024.1394019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Introduction Coxiella burnetii is a gram-negative obligate intracellular bacterium and a zoonotic pathogen that causes human Q fever. The lack of effective antibiotics and a licensed vaccine for Coxiella in the U.S. warrants further research into Coxiella pathogenesis. Within the host cells, Coxiella replicates in an acidic phagolysosome-like vacuole termed Coxiella-containing vacuole (CCV). Previously, we have shown that the CCV pH is critical for Coxiella survival and that the Coxiella Type 4B secretion system regulates CCV pH by inhibiting the host endosomal maturation pathway. However, the trafficking pattern of the 'immature' endosomes in Coxiella- infected cells remained unclear. Methods We transfected HeLa cells with GFP-tagged Rab proteins and subsequently infected them with mCherry-Coxiella to visualize Rab protein localization. Infected cells were immunostained with anti-Rab antibodies to confirm the Rab localization to the CCV, to quantitate Rab11a and Rab35- positive CCVs, and to quantitate total recycling endosome content of infected cells. A dual-hit siRNA mediated knockdown combined with either immunofluorescent assay or an agarose-based colony-forming unit assay were used to measure the effects of Rab11a and Rab35 knockdown on CCV area and Coxiella intracellular growth. Results The CCV localization screen with host Rab proteins revealed that recycling endosome-associated proteins Rab11a and Rab35 localize to the CCV during infection, suggesting that CCV interacts with host recycling endosomes during maturation. Interestingly, only a subset of CCVs were Rab11a or Rab35-positive at any given time point. Quantitation of Rab11a/Rab35-positive CCVs revealed that while Rab11a interacts with the CCV more at 3 dpi, Rab35 is significantly more prevalent at CCVs at 6 dpi, suggesting that the CCV preferentially interacts with Rab11a and Rab35 depending on the stage of infection. Furthermore, we observed a significant increase in Rab11a and Rab35 fluorescent intensity in Coxiella-infected cells compared to mock, suggesting that Coxiella increases the recycling endosome content in infected cells. Finally, siRNA-mediated knockdown of Rab11a and Rab35 resulted in significantly smaller CCVs and reduced Coxiella intracellular growth, suggesting that recycling endosomal Rab proteins are essential for CCV expansion and bacterial multiplication. Discussion Our data, for the first time, show that the CCV dynamically interacts with host recycling endosomes for Coxiella intracellular survival and potentially uncovers novel host cell factors essential for Coxiella pathogenesis.
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Affiliation(s)
- Brooke A. Hall
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
| | - Kristen E. Senior
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
| | - Nicolle T. Ocampo
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, United States
| | - Dhritiman Samanta
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
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2
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Vale-Costa S, Etibor TA, Brás D, Sousa AL, Ferreira M, Martins GG, Mello VH, Amorim MJ. ATG9A regulates the dissociation of recycling endosomes from microtubules to form liquid influenza A virus inclusions. PLoS Biol 2023; 21:e3002290. [PMID: 37983294 PMCID: PMC10695400 DOI: 10.1371/journal.pbio.3002290] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 12/04/2023] [Accepted: 10/13/2023] [Indexed: 11/22/2023] Open
Abstract
It is now established that many viruses that threaten public health establish condensates via phase transitions to complete their lifecycles, and knowledge on such processes may offer new strategies for antiviral therapy. In the case of influenza A virus (IAV), liquid condensates known as viral inclusions, concentrate the 8 distinct viral ribonucleoproteins (vRNPs) that form IAV genome and are viewed as sites dedicated to the assembly of the 8-partite genomic complex. Despite not being delimited by host membranes, IAV liquid inclusions accumulate host membranes inside as a result of vRNP binding to the recycling endocytic marker Rab11a, a driver of the biogenesis of these structures. We lack molecular understanding on how Rab11a-recycling endosomes condensate specifically near the endoplasmic reticulum (ER) exit sites upon IAV infection. We show here that liquid viral inclusions interact with the ER to fuse, divide, and slide. We uncover that, contrary to previous indications, the reported reduction in recycling endocytic activity is a regulated process rather than a competition for cellular resources involving a novel role for the host factor ATG9A. In infection, ATG9A mediates the removal of Rab11a-recycling endosomes carrying vRNPs from microtubules. We observe that the recycling endocytic usage of microtubules is rescued when ATG9A is depleted, which prevents condensation of Rab11a endosomes near the ER. The failure to produce viral inclusions accumulates vRNPs in the cytosol and reduces genome assembly and the release of infectious virions. We propose that the ER supports the dynamics of liquid IAV inclusions, with ATG9A facilitating their formation. This work advances our understanding on how epidemic and pandemic influenza genomes are formed. It also reveals the plasticity of recycling endosomes to undergo condensation in response to infection, disclosing new roles for ATG9A beyond its classical involvement in autophagy.
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Affiliation(s)
- Sílvia Vale-Costa
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Temitope Akhigbe Etibor
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Daniela Brás
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Ana Laura Sousa
- Electron Microscopy Facility (EMF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Mariana Ferreira
- Advanced Imaging Facility (AIF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Gabriel G. Martins
- Advanced Imaging Facility (AIF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Victor Hugo Mello
- Living Physics, Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Maria João Amorim
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
- Cell Biology of Viral Infection Lab (CBV), Católica Biomedical Research Centre (CBR), Católica Medical School—Universidade Católica Portuguesa, Lisboa, Portugal
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3
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Joseph I, Flores J, Farrell V, Davis J, Bianchi‐Smak J, Feng Q, Goswami S, Lin X, Wei Z, Tong K, Feng Z, Verzi MP, Bonder EM, Goldenring JR, Gao N. RAB11A and RAB11B control mitotic spindle function in intestinal epithelial progenitor cells. EMBO Rep 2023; 24:e56240. [PMID: 37424454 PMCID: PMC10481667 DOI: 10.15252/embr.202256240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 07/11/2023] Open
Abstract
RAB11 small GTPases and associated recycling endosome have been localized to mitotic spindles and implicated in regulating mitosis. However, the physiological significance of such regulation has not been observed in mammalian tissues. We have used newly engineered mouse models to investigate intestinal epithelial renewal in the absence of single or double isoforms of RAB11 family members: Rab11a and Rab11b. Comparing with single knockouts, mice with compound ablation demonstrate a defective cell cycle entry and robust mitotic arrest followed by apoptosis, leading to a total penetrance of lethality within 3 days of gene ablation. Upon Rab11 deletion ex vivo, enteroids show abnormal mitotic spindle formation and cell death. Untargeted proteomic profiling of Rab11a and Rab11b immunoprecipitates has uncovered a shared interactome containing mitotic spindle microtubule regulators. Disrupting Rab11 alters kinesin motor KIF11 function and impairs bipolar spindle formation and cell division. These data demonstrate that RAB11A and RAB11B redundantly control mitotic spindle function and intestinal progenitor cell division, a mechanism that may be utilized to govern the homeostasis and renewal of other mammalian tissues.
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Affiliation(s)
- Ivor Joseph
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
| | - Juan Flores
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
| | | | - Justin Davis
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
| | | | - Qiang Feng
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
| | | | - Xiang Lin
- Department of Computer SciencesNew Jersey Institute of TechnologyNewarkNJUSA
| | - Zhi Wei
- Department of Computer SciencesNew Jersey Institute of TechnologyNewarkNJUSA
| | - Kevin Tong
- Department of GeneticsRutgers UniversityNew BrunswickNJUSA
| | - Zhaohui Feng
- Rutgers Cancer Institute of New JerseyNew BrunswickNJUSA
| | | | - Edward M Bonder
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
| | - James R Goldenring
- Section of Surgical Sciences and Epithelial Biology CenterVanderbilt University Medical CenterNashvilleTNUSA
| | - Nan Gao
- Department of Biological SciencesRutgers UniversityNewarkNJUSA
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4
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Naslavsky N, Caplan S. Receptor-mediated internalization promotes increased endosome size and number in a RAB4- and RAB5-dependent manner. Eur J Cell Biol 2023; 102:151339. [PMID: 37423034 PMCID: PMC10585956 DOI: 10.1016/j.ejcb.2023.151339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/26/2023] [Accepted: 07/05/2023] [Indexed: 07/11/2023] Open
Abstract
Despite their significance in receptor-mediated internalization and continued signal transduction in cells, early/sorting endosomes (EE/SE) remain incompletely characterized, with many outstanding questions that surround the dynamics of their size and number. While several studies have reported increases in EE/SE size and number resulting from endocytic events, few studies have addressed such dynamics in a methodological and quantitative manner. Herein we apply quantitative fluorescence microscopy to measure the size and number of EE/SE upon internalization of two different ligands: transferrin and epidermal growth factor. Additionally, we used siRNA knock-down to determine the involvement of 5 different endosomal RAB proteins (RAB4, RAB5, RAB8A, RAB10 and RAB11A) in EE/SE dynamics. Our study provides new information on the dynamics of endosomes during endocytosis, an important reference for researchers studying receptor-mediated internalization and endocytic events.
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Affiliation(s)
- Naava Naslavsky
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Steve Caplan
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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5
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Tran MT, Okusha Y, Htike K, Sogawa C, Eguchi T, Kadowaki T, Sakai E, Tsukuba T, Okamoto K. HSP90 drives the Rab11a-mediated vesicular transport of the cell surface receptors in osteoclasts. Cell Biochem Funct 2022; 40:838-855. [PMID: 36111708 DOI: 10.1002/cbf.3745] [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: 03/13/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 12/15/2022]
Abstract
Rab11a, which ubiquitously localizes to early and recycling endosomes, is required for regulating the vesicular transport of cellular cargos. Interestingly, our previous study revealed that Rab11a served as a negative regulator of osteoclastogenesis by facilitating the lysosomal proteolysis of (1) colony-stimulating factor-1 (c-fms) receptor and (2) receptor activator of nuclear factor-κB (RANK) receptor, thereby resulting in inhibition of osteoclast (OC) differentiation, maturation, and bone-resorbing activity. However, the molecular mechanisms of how Rab11a negatively affected osteoclastogenesis were largely unknown. Heat shock protein (HSP90), including two isoforms HSP90α and HSP90β, necessitates the stability, maturation, and activity of a broad range of its clients, and is essentially required for a vast array of signal transduction pathways in nonstressful conditions. Furthermore, cumulative evidence suggests that HSP90 is a vital element of the vesicular transport network. Indeed, our recent study revealed that HSP90, a novel effector protein of Rab11b, modulated Rab11b-mediated osteoclastogenesis. In this study, we also found that Rab11a interacted with both HSP90α and HSP90β in OCs. Upon blockade of HSP90 ATPase activity by a specific inhibitor(17-allylamino-demethoxygeldanamycin), we showed that (1) the ATPase domain of HSP90 was a prerequisite for the interaction between HSP90 and Rab11a, and (2) the interaction of HSP90 to Rab11a sufficiently maintained the inhibitory effects of Rab11a on osteoclastogenesis. Altogether, our findings undoubtedly indicate a novel role of HSP90 in regulating Rab11a-mediated osteoclastogenesis.
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Affiliation(s)
- Manh Tien Tran
- Department of Dental Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Yuka Okusha
- Department of Radiation Oncology, Division of Molecular and Cellular Biology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Kaung Htike
- Department of Dental Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Chiharu Sogawa
- Department of Clinical Engineering, Faculty of Life Sciences, Hiroshima Institute of Technology, Hiroshima, Japan
| | - Takanori Eguchi
- Department of Dental Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,Advanced Research Center for Oral and Craniofacial Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Tomoko Kadowaki
- Department of Frontier Oral Science, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Eiko Sakai
- Department of Dental Pharmacology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Takayuki Tsukuba
- Department of Dental Pharmacology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Kuniaki Okamoto
- Department of Dental Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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6
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Chen M, Zhang Y, Jiang K, Wang W, Feng H, Zhen R, Moo C, Zhang Z, Shi J, Chen C. Grab regulates transferrin receptor recycling and iron uptake in developing erythroblasts. Blood 2022; 140:1145-1155. [PMID: 35820059 DOI: 10.1182/blood.2021015189] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 06/25/2022] [Indexed: 11/20/2022] Open
Abstract
Developing erythroblasts acquire massive amounts of iron through the transferrin (Tf) cycle, which involves endocytosis, sorting, and recycling of the Tf-Tf receptor (Tfrc) complex. Previous studies on the hemoglobin-deficit (hbd) mouse have shown that the exocyst complex is indispensable for the Tfrc recycling; however, the precise mechanism underlying the efficient exocytosis and recycling of Tfrc in erythroblasts remains unclear. Here, we identify the guanine nucleotide exchange factor Grab as a critical regulator of the Tf cycle and iron metabolism during erythropoiesis. Grab is highly expressed in differentiating erythroblasts. Loss of Grab diminishes the Tfrc recycling and iron uptake, leading to hemoglobinization defects in mouse primary erythroblasts, mammalian erythroleukemia cells, and zebrafish embryos. These defects can be alleviated by supplementing iron together with hinokitiol, a small-molecule natural compound that can mediate iron transport independent of the Tf cycle. Mechanistically, Grab regulates the exocytosis of Tfrc-associated vesicles by activating the GTPase Rab8, which subsequently promotes the recruitment of the exocyst complex and vesicle exocytosis. Our results reveal a critical role for Grab in regulating the Tf cycle and provide new insights into iron homeostasis and erythropoiesis.
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Affiliation(s)
- Mengying Chen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yuhan Zhang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Kailun Jiang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Weixi Wang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - He Feng
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ru Zhen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Chingyee Moo
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Zhuonan Zhang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jiahai Shi
- Synthetic Biology Translational Research Programs, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and
| | - Caiyong Chen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
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7
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Ciesielska A, Matyjek M, Kwiatkowska K. TLR4 and CD14 trafficking and its influence on LPS-induced pro-inflammatory signaling. Cell Mol Life Sci 2020; 78:1233-1261. [PMID: 33057840 PMCID: PMC7904555 DOI: 10.1007/s00018-020-03656-y] [Citation(s) in RCA: 568] [Impact Index Per Article: 142.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/25/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023]
Abstract
Toll-like receptor (TLR) 4 belongs to the TLR family of receptors inducing pro-inflammatory responses to invading pathogens. TLR4 is activated by lipopolysaccharide (LPS, endotoxin) of Gram-negative bacteria and sequentially triggers two signaling cascades: the first one involving TIRAP and MyD88 adaptor proteins is induced in the plasma membrane, whereas the second engaging adaptor proteins TRAM and TRIF begins in early endosomes after endocytosis of the receptor. The LPS-induced internalization of TLR4 and hence also the activation of the TRIF-dependent pathway is governed by a GPI-anchored protein, CD14. The endocytosis of TLR4 terminates the MyD88-dependent signaling, while the following endosome maturation and lysosomal degradation of TLR4 determine the duration and magnitude of the TRIF-dependent one. Alternatively, TLR4 may return to the plasma membrane, which process is still poorly understood. Therefore, the course of the LPS-induced pro-inflammatory responses depends strictly on the rates of TLR4 endocytosis and trafficking through the endo-lysosomal compartment. Notably, prolonged activation of TLR4 is linked with several hereditary human diseases, neurodegeneration and also with autoimmune diseases and cancer. Recent studies have provided ample data on the role of diverse proteins regulating the functions of early, late, and recycling endosomes in the TLR4-induced inflammation caused by LPS or phagocytosis of E. coli. In this review, we focus on the mechanisms of the internalization and intracellular trafficking of TLR4 and CD14, and also of LPS, in immune cells and discuss how dysregulation of the endo-lysosomal compartment contributes to the development of diverse human diseases.
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Affiliation(s)
- Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland.
| | - Marta Matyjek
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland
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8
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Hasanin AH, Matboli M, Seleem HS. Hesperidin suppressed hepatic precancerous lesions via modulation of exophagy in rats. J Cell Biochem 2019; 121:1295-1306. [PMID: 31489981 DOI: 10.1002/jcb.29363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/23/2019] [Indexed: 12/21/2022]
Abstract
The enormous cost of modern medicines warrants alternative strategies for the better management of hepatocellular carcinoma. Recently, exosomes have been shown to relay the oncogenic information through the horizontal transfer of RNAs between the cells. In this study, we modulated exosomal production and autophagy (exophagy) by the administration of hesperidin and evaluated its effect on the development of hepatic precancerous lesion (HPC) in rats. Diethylnitrosamine and 2-acetylaminofluorene were used in vivo to induce HPC in rats. Rats were allocated into five groups: naïve, HPC, and three hesperidin treated (50, 100, and 200 mg/kg/d; orally) for 4 consecutive days per week for 16 weeks. Liver tissues and blood samples were collected for histopathological, immunohistochemical, and transmission electron microscope examinations, liver function, alfa-fetoprotein level, and isolation of exosomal and autophagy RNAs. Hesperidin administration showed hepato-protective effects and improved the microscopic hepatic features with a decrease in glutathione S-transferase placental precancerous foci and the abundance of exosomes in liver tissues. Hesperidin improved liver function with a significant decrease in alfa-fetoprotein levels. Hesperidin dose-dependently decreased exosomal RAB11A messsenger RNA and long noncoding RNA-RP11-583F2.2 along with the increase in exosomal miR-1298, involved in the exophagy process. In conclusion, hesperidin likely suppresses liver carcinogenesis in rat model via the modulation of exosomal secretion and autophagy.
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Affiliation(s)
- Amany H Hasanin
- Department of Clinical Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Marwa Matboli
- Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Hanan S Seleem
- Department of Histology, Faculty of Medicine, Menoufia University, Cairo, Egypt.,Histology Department, Faculty of Medicine, Unaizah College of Medicine, Al Qassim University, Buraydah, KSA
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A role for Rab11 in the homeostasis of the endosome-lysosomal pathway. Exp Cell Res 2019; 380:55-68. [PMID: 30981667 DOI: 10.1016/j.yexcr.2019.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/31/2019] [Accepted: 04/08/2019] [Indexed: 12/26/2022]
Abstract
The small GTPases Rab11a and 11b are key regulators of membrane transport, localised to the recycling endosomes and also early endosomes. The function of Rab11 within the recycling pathway has been well defined, however, the role of Rab11 at the early endosomes remains poorly characterised. Here, we have generated HeLa cell lines devoid of either Rab11a or Rab11b using CRISPR/Cas9 to functionally dissect the roles of these two Rab11 family members in recycling and in the endosomal-lysosomal system. Both Rab11a and Rab11b contribute to the dynamics of tubulation arising from recycling endosomes whereas Rab11a has the major role in recycling of transferrin receptor. Deletion of either Rab11a or Rab11b resulted in the formation of enlarged early endosomes and perturbation of the endosomal-lysosomal pathway. Strikingly, Rab11a knock-out cells showed an increased density of functional late endosomes/lysosomes as well as lysotracker-positive organelles which were primarily concentrated in a perinuclear location, indicating that the homeostasis of the endosome/lysosome pathway had been perturbed. Moreover, in Rab11a knockout cells there was a functional defect in the intracellular recycling of the cation-independent mannose 6-phosphate receptor (CI-M6PR) between the late endosomes and the TGN, a defect associated with enhanced degradation of CI-M6PR. Expression of wild-type Rab11a in Rab11a knockout cells rescued the late endosome/lysosome phenotype. Overall, these results indicate that Rab11a and Rab11b have overlapping and distinct functions and that Rab11a, unexpectedly, plays a central role in the homeostasis of endosomal-lysosomal biogenesis.
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Yun JS, Ha SC, Kim S, Kim YG, Kim H, Chang JH. Crystal structure of Arabidopsis thaliana RabA1a. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:93-109. [PMID: 30010245 DOI: 10.1111/jipb.12700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/11/2018] [Indexed: 06/08/2023]
Abstract
RabGTPase is a member of the Ras superfamily of small GTPases, which share a GTP-binding pocket containing highly conserved motifs that promote GTP hydrolysis. In Arabidopsis, the RabA group, which corresponds to the Rab11 group in animals, functions in the recycling of endosomes that control docking and fusion during vesicle transport. However, their molecular mechanisms remain unknown. In this study, we determined the crystal structures of the GDP-bound inactive form and both GppNHp- and GTP-bound active forms of RabA1a, at resolutions of 2.8, 2.6, and 2.6 Å, respectively. A bound sulfate ion in the active site of the GDP-bound structure stabilized Switch II by bridging the interaction between a magnesium ion and Arg74. Comparisons of the two states of RabA1a with Rab11 proteins revealed clear differences in the Switch I and II loops. These results suggested that conformational change of the Switch regions of RabA1a, derived by GTP or GDP binding, could maintain subcellular membrane traffic through the specific interaction of effector molecules.
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Affiliation(s)
- Ji-Sook Yun
- Department of Biology Education, Kyungpook National University, Daehak-ro 80, Daegu 41566, South Korea
| | - Sung Chul Ha
- Beamline Science Division, Pohang Accelerator Laboratory, Jigok-ro 127, Pohang 37673, South Korea
| | - Shinae Kim
- Department of Biology Education, Kyungpook National University, Daehak-ro 80, Daegu 41566, South Korea
| | - Yeon-Gil Kim
- Beamline Science Division, Pohang Accelerator Laboratory, Jigok-ro 127, Pohang 37673, South Korea
| | - Hyeran Kim
- Department of Biological Sciences, Kangwon National University, Kangwondaehak-gil 1, Chuncheon 24341, South Korea
| | - Jeong Ho Chang
- Department of Biology Education, Kyungpook National University, Daehak-ro 80, Daegu 41566, South Korea
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11
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Blanc L, Vidal M. New insights into the function of Rab GTPases in the context of exosomal secretion. Small GTPases 2017; 9:95-106. [PMID: 28135905 PMCID: PMC5902209 DOI: 10.1080/21541248.2016.1264352] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In the last two decades, extracellular vesicle-mediated communication between cells has become a major field in cell biology. However, the function of extracellular vesicles is far from clear, especially due to the disparity of released vesicles by cells. Basically, one must consider vesicles budding from the cell plasma membrane (ectosomes) and vesicles released upon fusion of an endosomal multivesicular compartment (exosomes). Moreover, even for exosomes, we report and discuss here the possibility that different routes regulated by specific Rab GTPases might produce exosomes having various biologic functions.
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Affiliation(s)
- Lionel Blanc
- a Laboratory of Developmental Erythropoiesis, The Feinstein Institute for Medical Research Hofstra Northwell School of Medicine , Manhasset , NY , USA
| | - Michel Vidal
- b UMR 5235, CNRS, Université Montpellier , cc107, Montpellier , France
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12
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Amaya C, Militello RD, Calligaris SD, Colombo MI. Rab24 interacts with the Rab7/Rab interacting lysosomal protein complex to regulate endosomal degradation. Traffic 2016; 17:1181-1196. [PMID: 27550070 DOI: 10.1111/tra.12431] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 08/17/2016] [Accepted: 08/17/2016] [Indexed: 12/11/2022]
Abstract
Endocytosis is a multistep process engaged in extracellular molecules internalization. Several proteins including the Rab GTPases family coordinate the endocytic pathway. The small GTPase Rab7 is present in late endosome (LE) compartments being a marker of endosome maturation. The Rab interacting lysosomal protein (RILP) is a downstream effector of Rab7 that recruits the functional dynein/dynactin motor complex to late compartments. In the present study, we have found Rab24 as a component of the endosome-lysosome degradative pathway. Rab24 is an atypical protein of the Rab GTPase family, which has been attributed a function in vesicle trafficking and autophagosome maturation. Using a model of transiently expressed proteins in K562 cells, we found that Rab24 co-localizes in vesicular structures labeled with Rab7 and LAMP1. Moreover, using a dominant negative mutant of Rab24 or a siRNA-Rab24 we showed that the distribution of Rab7 in vesicles depends on a functional Rab24 to allow DQ-BSA protein degradation. Additionally, by immunoprecipitation and pull down assays, we have demonstrated that Rab24 interacts with Rab7 and RILP. Interestingly, overexpression of the Vps41 subunit from the homotypic fusion and protein-sorting (HOPS) complex hampered the co-localization of Rab24 with RILP or with the lysosomal GTPase Arl8b, suggesting that Vps41 would affect the Rab24/RILP association. In summary, our data strongly support the hypothesis that Rab24 forms a complex with Rab7 and RILP on the membranes of late compartments. Our work provides new insights into the molecular function of Rab24 in the last steps of the endosomal degradative pathway.
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Affiliation(s)
- Celina Amaya
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Rodrigo D Militello
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Sebastián D Calligaris
- Centro de Medicina Regenerativa, Facultad de Medicina, Universidad del Desarrollo Clínica Alemana, Santiago, Chile
| | - María I Colombo
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
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13
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Schafer JC, McRae RE, Manning EH, Lapierre LA, Goldenring JR. Rab11-FIP1A regulates early trafficking into the recycling endosomes. Exp Cell Res 2016; 340:259-73. [PMID: 26790954 PMCID: PMC4744548 DOI: 10.1016/j.yexcr.2016.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 12/19/2015] [Accepted: 01/10/2016] [Indexed: 12/31/2022]
Abstract
The Rab11 family of small GTPases, along with the Rab11-family interacting proteins (Rab11-FIPs), are critical regulators of intracellular vesicle trafficking and recycling. We have identified a point mutation of Threonine-197 site to an Alanine in Rab11-FIP1A, which causes a dramatic dominant negative phenotype when expressed in HeLa cells. The normally perinuclear distribution of GFP-Rab11-FIP1A was condensed into a membranous cisternum with almost no GFP-Rab11-FIP1A(T197A) remaining outside of this central locus. Also, this condensed GFP-FIP1A(T197A) altered the distribution of proteins in the Rab11a recycling pathway including endogenous Rab11a, Rab11-FIP1C, and transferrin receptor (CD71). Furthermore, this condensed GFP-FIP1A(T197A)-containing structure exhibited little movement in live HeLa cells. Expression of GFP-FIP1A(T197A) caused a strong blockade of transferrin recycling. Treatment of cells expressing GFP-FIP1A(T197A) with nocodazole did not disperse the Rab11a-containing recycling system. We also found that Rab5 and EEA1 were accumulated in membranes by GFP-Rab11-FIP1A but Rab4 was unaffected, suggesting that a direct pathway may exist from early endosomes into the Rab11a-containing recycling system. Our study of a potent inhibitory trafficking mutation in Rab11-FIP1A shows that Rab11-FIP1A associates with and regulates trafficking at an early step in the process of membrane recycling.
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Affiliation(s)
- Jenny C Schafer
- Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA
| | - Rebecca E McRae
- Departments of Surgery, Nashville, TN, USA; Cell & Developmental Biology, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA
| | - Elizabeth H Manning
- Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA
| | - Lynne A Lapierre
- Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA
| | - James R Goldenring
- Departments of Surgery, Nashville, TN, USA; Cell & Developmental Biology, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA; Vanderbilt University School of Medicine and the Nashville VA Medical Center, Nashville, TN, USA.
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14
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Sunada M, Goh T, Ueda T, Nakano A. Functional analyses of the plant-specific C-terminal region of VPS9a: the activating factor for RAB5 in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2016; 129:93-102. [PMID: 26493488 DOI: 10.1007/s10265-015-0760-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/17/2015] [Indexed: 05/23/2023]
Abstract
Recent studies demonstrated that endosomal transport played important roles in various plant functions. The RAB GTPase regulates the tethering and fusion steps of vesicle trafficking to target membranes in each trafficking pathway by acting as a molecular switch. RAB GTPase activation is catalyzed by specific guanine nucleotide exchange factors (GEFs) that promote the exchange of GDP on the RAB GTPase with GTP. RAB5 is a key regulator of endosomal trafficking and is uniquely diversified in plants; the plant-unique RAB5 group ARA6 was acquired in addition to conventional RAB5 during evolution. In Arabidopsis thaliana, conventional RAB5, ARA7 and RHA1 regulate the endosomal/vacuolar trafficking pathways, whereas ARA6 acts in the pathway from the endosome to the plasma membrane. Despite their distinct functions, all RAB5 members are activated by the common GEF VACUOLAR PROTEIN SORTING 9a (VPS9a). VPS9a consists of an N-terminal conserved domain and C-terminal region (CTR) with no similarity to known functional domains. In this study, we investigated the function of the CTR by generating truncated versions of VPS9a and found that it was specifically responsible for ARA6 regulation; moreover, the CTR was required for the oligomerization and correct localization of VPS9a. The oligomerization of VPS9a was mediated by a distinctive region consisting of 36 amino acids in the CTR that was conserved in plant RAB5 GEFs. Thus the VPS9a CTR plays an important role in the regulation of the two RAB5 groups in plants.
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Affiliation(s)
- Mariko Sunada
- Department of Biological Sciences, Graduate School of Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tatsuaki Goh
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Takashi Ueda
- Department of Biological Sciences, Graduate School of Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advances Photonics, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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15
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Bazdar DA, Kalinowska M, Panigrahi S, Sieg SF. Recycled IL-7 Can Be Delivered to Neighboring T Cells. THE JOURNAL OF IMMUNOLOGY 2015; 194:4698-704. [PMID: 25870237 DOI: 10.4049/jimmunol.1400560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 03/12/2015] [Indexed: 01/07/2023]
Abstract
IL-7 is a key homeostatic cytokine that provides signals for T cell survival and proliferation in vivo. In this article, we provide evidence that IL-7 utilization is enhanced by a novel mechanism of cytokine "recycling" during which T cells treated with rIL-7 are rapidly induced to express p-STAT5 and are subsequently able to recycle biologically active cytokine for release to neighboring cells in soluble form. Our observations indicate that the ability of cells to recycle IL-7 is dependent on IL-7R α-chain (CD127) and endocytosis, consistent with a model whereby IL-7 is internalized via receptor interactions before recycling. These observations provide evidence of a novel mechanism that enables cells to optimally use IL-7.
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Affiliation(s)
- Douglas A Bazdar
- Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106; and
| | | | - Soumya Panigrahi
- Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106; and
| | - Scott F Sieg
- Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106; and
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16
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Knowles BC, Weis VG, Yu S, Roland JT, Williams JA, Alvarado GS, Lapierre LA, Shub MD, Gao N, Goldenring JR. Rab11a regulates syntaxin 3 localization and microvillus assembly in enterocytes. J Cell Sci 2015; 128:1617-26. [PMID: 25673875 DOI: 10.1242/jcs.163303] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/02/2015] [Indexed: 02/02/2023] Open
Abstract
Rab11a is a key component of the apical recycling endosome that aids in the trafficking of proteins to the luminal surface in polarized epithelial cells. Utilizing conditional Rab11a-knockout specific to intestinal epithelial cells, and human colonic epithelial CaCo2-BBE cells with stable Rab11a knockdown, we examined the molecular and pathological impact of Rab11a deficiency on the establishment of apical cell polarity and microvillus morphogenesis. We demonstrate that loss of Rab11a induced alterations in enterocyte polarity, shortened microvillar length and affected the formation of microvilli along the lateral membranes. Rab11a deficiency in enterocytes altered the apical localization of syntaxin 3. These data affirm the role of Rab11a in apical membrane trafficking and the maintenance of apical microvilli in enterocytes.
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Affiliation(s)
- Byron C Knowles
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Victoria G Weis
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Shiyan Yu
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Joseph T Roland
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Janice A Williams
- Vanderbilt Ingraham Cancer Center: Cell Imaging Shared Resource, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Gabriela S Alvarado
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Lynne A Lapierre
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Mitchell D Shub
- Phoenix Children's Hospital and the Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA Rutgers Cancer Institute of New Jersey, Piscataway, NJ 08903, USA
| | - James R Goldenring
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
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17
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Smith NL, Hammond S, Gadi D, Wagenknecht-Wiesner A, Baird B, Holowka D. Sphingosine derivatives inhibit cell signaling by electrostatically neutralizing polyphosphoinositides at the plasma membrane. SELF NONSELF 2014; 1:133-143. [PMID: 21423874 DOI: 10.4161/self.1.2.11672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mast cell stimulation via IgE receptors causes activation of multiple processes, including Ca(2+) mobilization, granule exocytosis, and outward trafficking of recycling endosomes to the plasma membrane. We used fluorescein-conjugated cholera toxin B (FITC-CTxB) to label GM(1) in recycling endsomes and to monitor antigen-stimulated trafficking to the plasma membrane in both fluorimeter and imaging-based assays. We find that the sphingosine derivatives D-sphingosine and N,N'-dimethylsphingosine effectively inhibit this outward trafficking response, whereas a quarternary ammonium derivative, N,N',N″-trimethylsphingosine, does not inhibit. This pattern of inhibition is also found for Ca(2+) mobilization and secretory lysosomal exocytosis, indicating a general effect on Ca(2+)-dependent signaling processes. This inhibition correlates with the capacity of sphingosine derivatives to flip to the inner leaflet of the plasma membrane that is manifested as changes in plasma membrane-associated FITC-CTxB fluorescence and cytoplasmic pH. Using a fluorescently labeled MARCKS effector domain to monitor plasma membrane-associated polyphosphoinositides, we find that these sphingosine derivatives displace the electrostatic binding of this MARCKS effector domain to the plasma membrane in parallel with their capacity to inhibit Ca(2+)-dependent signaling. Our results support roles for plasma membrane polyphosphoinositides in Ca(2+) signaling and stimulated exocytosis, and they illuminate a mechanism by which D-sphingosine regulates signaling responses in mammalian cells.
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Affiliation(s)
- Norah L Smith
- Department of Chemistry and Chemical Biology; Cornell University; Ithaca, NY USA
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18
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Maringer K, Saheb E, Bush J. Vesicular Trafficking Defects, Developmental Abnormalities, and Alterations in the Cellular Death Process Occur in Cell Lines that Over-Express Dictyostelium GTPase, Rab2, and Rab2 Mutants. BIOLOGY 2014; 3:514-35. [PMID: 25157910 PMCID: PMC4192625 DOI: 10.3390/biology3030514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/29/2014] [Accepted: 08/13/2014] [Indexed: 01/10/2023]
Abstract
Small molecular weight GTPase Rab2 has been shown to be a resident of pre-Golgi intermediates and required for protein transport from the ER to the Golgi complex, however, the function of Rab2 in Dictyostelium has yet to be fully characterized. Using cell lines that over-express DdRab2, as well as cell lines over-expressing constitutively active (CA), and dominant negative (DN) forms of the GTPase, we report a functional role in vesicular transport specifically phagocytosis, and endocytosis. Furthermore, Rab2 like other GTPases cycles between an active GTP-bound and an inactive GDP-bound state. We found that this GTP/GDP cycle for DdRab2 is crucial for normal Dictyostelium development and cell-cell adhesion. Similar to Rab5 and Rab7 in C. elegans, we found that DdRab2 plays a role in programmed cell death, possibly in the phagocytic removal of apoptotic corpses.
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Affiliation(s)
- Katherine Maringer
- Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA.
| | - Entsar Saheb
- Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA.
| | - John Bush
- Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA.
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19
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Mukhopadhyay A, Quiroz JA, Wolkoff AW. Rab1a regulates sorting of early endocytic vesicles. Am J Physiol Gastrointest Liver Physiol 2014; 306:G412-24. [PMID: 24407591 PMCID: PMC3949023 DOI: 10.1152/ajpgi.00118.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We previously reported that Rab1a is associated with asialoorosomucoid (ASOR)-containing early endocytic vesicles, where it is required for their microtubule-based motility. In Rab1a knockdown (KD) cell lines, ASOR failed to segregate from its receptor and, consequently, did not reach lysosomes for degradation, indicating a defect in early endosome sorting. Although Rab1 is required for Golgi/endoplasmic reticulum trafficking, this process was unaffected, likely due to retained expression of Rab1b in these cells. The present study shows that Rab1a has a more general role in endocytic vesicle processing that extends to EGF and transferrin (Tfn) trafficking. Compared with results in control Huh7 cells, EGF accumulated in aggregates within Rab1a KD cells, failing to reach lysosomal compartments. Tfn, a prototypical example of recycling cargo, accumulated in a Rab11-mediated slow-recycling compartment in Rab1a KD cells, in contrast to control cells, which sort Tfn into a fast-recycling Rab4 compartment. These data indicate that Rab1a is an important regulator of early endosome sorting for multiple cargo species. The effectors and accessory proteins recruited by Rab1a to early endocytic vesicles include the minus-end-directed kinesin motor KifC1, while others remain to be discovered.
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Affiliation(s)
- Aparna Mukhopadhyay
- 1Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York; ,2Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Jose A. Quiroz
- 4Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Allan W. Wolkoff
- 1Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York; ,2Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York; ,3Division of Gastroenterology and Liver Diseases, Albert Einstein College of Medicine, Bronx, New York; and
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20
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Asaoka R, Uemura T, Ito J, Fujimoto M, Ito E, Ueda T, Nakano A. Arabidopsis RABA1 GTPases are involved in transport between the trans-Golgi network and the plasma membrane, and are required for salinity stress tolerance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:240-9. [PMID: 22974509 DOI: 10.1111/tpj.12023] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/31/2012] [Accepted: 09/10/2012] [Indexed: 05/20/2023]
Abstract
RAB GTPases are key regulators of membrane traffic. Among them, RAB11, a widely conserved sub-group, has evolved in a unique way in plants; plant RAB11 members show notable diversity, whereas yeast and animals have only a few RAB11 members. Fifty-seven RAB GTPases are encoded in the Arabidopsis thaliana genome, 26 of which are classified in the RAB11 group (further divided into RABA1-RABA6 sub-groups). Although several plant RAB11 members have been shown to play pivotal roles in plant-unique developmental processes, including cytokinesis and tip growth, molecular and physiological functions of the majority of RAB11 members remain unknown. To reveal precise functions of plant RAB11, we investigated the subcellular localization and dynamics of the largest sub-group of Arabidopsis RAB11, RABA1, which has nine members. RABA1 members reside on mobile punctate structures adjacent to the trans-Golgi network and co-localized with VAMP721/722, R-SNARE proteins that operate in the secretory pathway. In addition, the constitutive-active mutant of RABA1b, RABA1b(Q72L) , was present on the plasma membrane. The RABA1b -containing membrane structures showed actin-dependent dynamic motion . Vesicles labeled by GFP-RABA1b moved dynamically, forming queues along actin filaments. Interestingly, Arabidopsis plants whose four major RABA1 members were knocked out, and those expressing the dominant-negative mutant of RABA1B, exhibited hypersensitivity to salinity stress. Altogether, these results indicate that RABA1 members mediate transport between the trans-Golgi network and the plasma membrane, and are required for salinity stress tolerance.
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Affiliation(s)
- Rin Asaoka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tomohiro Uemura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Jun Ito
- Molecular Membrane Biology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, 351-0198, Japan
| | - Masaru Fujimoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Emi Ito
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takashi Ueda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Molecular Membrane Biology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, 351-0198, Japan
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21
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Tsvetanova NG, Riordan DP, Brown PO. The yeast Rab GTPase Ypt1 modulates unfolded protein response dynamics by regulating the stability of HAC1 RNA. PLoS Genet 2012; 8:e1002862. [PMID: 22844259 PMCID: PMC3406009 DOI: 10.1371/journal.pgen.1002862] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 06/12/2012] [Indexed: 11/19/2022] Open
Abstract
The unfolded protein response (UPR) is a conserved mechanism that mitigates accumulation of unfolded proteins in the ER. The yeast UPR is subject to intricate post-transcriptional regulation, involving recruitment of the RNA encoding the Hac1 transcription factor to the ER and its unconventional splicing. To investigate the mechanisms underlying regulation of the UPR, we screened the yeast proteome for proteins that specifically interact with HAC1 RNA. Protein microarray experiments revealed that HAC1 interacts specifically with small ras GTPases of the Ypt family. We characterized the interaction of HAC1 RNA with one of these proteins, the yeast Rab1 homolog Ypt1. We found that Ypt1 protein specifically associated in vivo with unspliced HAC1 RNA. This association was disrupted by conditions that impaired protein folding in the ER and induced the UPR. Also, the Ypt1-HAC1 interaction depended on IRE1 and ADA5, the two genes critical for UPR activation. Decreasing expression of the Ypt1 protein resulted in a reduced rate of HAC1 RNA decay, leading to significantly increased levels of both unspliced and spliced HAC1 RNA, and delayed attenuation of the UPR, when ER stress was relieved. Our findings establish that Ypt1 contributes to regulation of UPR signaling dynamics by promoting the decay of HAC1 RNA, suggesting a potential regulatory mechanism for linking vesicle trafficking to the UPR and ER homeostasis.
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Affiliation(s)
- Nikoleta G Tsvetanova
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
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22
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Inactivation of MYO5B promotes invasion and motility in gastric cancer cells. Dig Dis Sci 2012; 57:1247-52. [PMID: 22134786 DOI: 10.1007/s10620-011-1989-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 11/15/2011] [Indexed: 12/22/2022]
Abstract
BACKGROUND Loss of cell polarity and tissue disorganisation are hallmarks of cancer. MYO5B mutations disrupt epithelial cell polarity, suggesting that MYO5B may be involved in tumorigenesis. METHODS We analyzed MYO5B expression in 70 gastric cancer tissues by immunohistochemistry using a tissue microarray method. Two related proteins, Rab11a and TfR, were also investigated. RESULTS We found that the negative rate of MYO5B was 78.6 and 17.1% in gastric cancer and normal gastric tissues (P < 0.001), respectively. The MYO5B expression had a strong relationship with Rab11a expression (P = 0.002). We also found that inactivation by siRNA against MYO5B promoted the proliferation, invasion and migration of gastric cancer cells. CONCLUSION The expression of MYO5B was downregulated in gastric cancer and inactivation of MYO5B may contribute to tumorigenesis. Therefore, MYO5B may become an important biomarker for gastric cancer in the future.
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23
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St. Pierre CA, Leonard D, Corvera S, Kurt-Jones EA, Finberg RW. Antibodies to cell surface proteins redirect intracellular trafficking pathways. Exp Mol Pathol 2011; 91:723-32. [PMID: 21819978 PMCID: PMC3315679 DOI: 10.1016/j.yexmp.2011.05.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 01/26/2023]
Abstract
Antibody-mediated intracellular delivery of therapeutic agents has been considered for treatment of a variety of diseases. These approaches involve targeting cell-surface receptor proteins expressed by tumors or viral proteins expressed on infected cells. We examined the intracellular trafficking of a viral cell-surface-expressed protein, rabies G, with or without binding a specific antibody, ARG1. We found that antibody binding shifts the native intracellular trafficking pathway of rabies G in an Fc-independent manner. Kinetic studies indicate that the ARG1/rabies G complex progressively co-localized with clathrin, early endosomes, late endosomes, and lysosomes after addition to cells. This pathway was different from that taken by rabies G without addition of antibody, which localized with recycling endosomes. Findings were recapitulated using a cellular receptor with a well-defined endogenous recycling pathway. We conclude that antibody binding to cell-surface proteins induces redirection of intracellular trafficking of unbound or ligand bound receptors to a specific degradation pathway. These findings have broad implications for future developments of antibody-based therapeutics.
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Affiliation(s)
- Christine A. St. Pierre
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605
| | - Deborah Leonard
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605
| | - Silvia Corvera
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605
| | - Evelyn A. Kurt-Jones
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605
| | - Robert W. Finberg
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605
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24
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Zaarour N, Defontaine N, Demaretz S, Azroyan A, Cheval L, Laghmani K. Secretory carrier membrane protein 2 regulates exocytic insertion of NKCC2 into the cell membrane. J Biol Chem 2011; 286:9489-502. [PMID: 21205824 DOI: 10.1074/jbc.m110.166546] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The renal-specific Na-K-2Cl co-transporter, NKCC2, plays a pivotal role in regulating body salt levels and blood pressure. NKCC2 mutations lead to type I Bartter syndrome, a life-threatening kidney disease. Regulation of NKCC2 trafficking behavior serves as a major mechanism in controlling NKCC2 activity across the plasma membrane. However, the identities of the protein partners involved in cell surface targeting of NKCC2 are largely unknown. To gain insight into these processes, we used a yeast two-hybrid system to screen a kidney cDNA library for proteins that interact with the NKCC2 C terminus. One binding partner we identified was SCAMP2 (secretory carrier membrane protein 2). Microscopic confocal imaging and co-immunoprecipitation assays confirmed NKCC2-SCAMP2 interaction in renal cells. SCAMP2 associated also with the structurally related co-transporter NCC, suggesting that the interaction with SCAMP2 is a common feature of sodium-dependent chloride co-transporters. Heterologous expression of SCAMP2 specifically decreased cell surface abundance as well as transport activity of NKCC2 across the plasma membrane. Co-immunolocalization experiments revealed that intracellularly retained NKCC2 co-localizes with SCAMP2 in recycling endosomes. The rate of NKCC2 endocytic retrieval, assessed by the sodium 2-mercaptoethane sulfonate cleavage assay, was not affected by SCAMP2. The surface-biotinylatable fraction of newly inserted NKCC2 in the plasma membrane was reduced by SCAMP2, demonstrating that SCAMP2-induced decrease in surface NKCC2 is due to decreased exocytotic trafficking. Finally, a single amino acid mutation, cysteine 201 to alanine, within the conserved cytoplasmic E peptide of SCAMP2, which is believed to regulate exocytosis, abolished SCAMP2-mediated down-regulation of the co-transporter. Taken together, these data are consistent with a model whereby SCAMP2 regulates NKCC2 transit through recycling endosomes and limits the cell surface targeting of the co-transporter by interfering with its exocytotic trafficking.
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Affiliation(s)
- Nancy Zaarour
- INSERM, Centre de Recherche des Cordeliers, UMRS 872, CNRS, ERL7226, 75006 Paris, France
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25
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Johnson BA, Wang J, Taylor EM, Caillier SJ, Herbert J, Khan OA, Cross AH, De Jager PL, Gourraud PAF, Cree BCA, Hauser SL, Oksenberg JR. Multiple sclerosis susceptibility alleles in African Americans. Genes Immun 2010; 11:343-50. [PMID: 19865102 PMCID: PMC2880217 DOI: 10.1038/gene.2009.81] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/11/2009] [Accepted: 09/15/2009] [Indexed: 12/24/2022]
Abstract
Multiple sclerosis (MS) is an autoimmune demyelinating disease characterized by complex genetics and multifaceted gene-environment interactions. Compared to whites, African Americans have a lower risk for developing MS, but African Americans with MS have a greater risk of disability. These differences between African Americans and whites may represent differences in genetic susceptibility and/or environmental factors. SNPs from 12 candidate genes have recently been identified and validated with MS risk in white populations. We performed a replication study using 918 cases and 656 unrelated controls to test whether these candidate genes are also associated with MS risk in African Americans. CD6, CLEC16a, EVI5, GPC5, and TYK2 contained SNPs that are associated with MS risk in the African American data set. EVI5 showed the strongest association outside the major histocompatibility complex (rs10735781, OR=1.233, 95% CI=1.06-1.43, P-value=0.006). In addition, RGS1 seems to affect age of onset whereas TNFRSF1A seems to be associated with disease progression. None of the tested variants showed results that were statistically inconsistent with the effects established in whites. The results are consistent with shared disease genetic mechanisms among individuals of European and African ancestry.
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Affiliation(s)
- B A Johnson
- Department of Neurology, University of California, San Francisco, CA 94143, USA
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26
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Mutant huntingtin impairs vesicle formation from recycling endosomes by interfering with Rab11 activity. Mol Cell Biol 2009; 29:6106-16. [PMID: 19752198 DOI: 10.1128/mcb.00420-09] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Huntingtin (Htt) localizes to endosomes, but its role in the endocytic pathway is not established. Recently, we found that Htt is important for the activation of Rab11, a GTPase involved in endosomal recycling. Here we studied fibroblasts of healthy individuals and patients with Huntington's disease (HD), which is a movement disorder caused by polyglutamine expansion in Htt. The formation of endocytic vesicles containing transferrin at plasma membranes was the same in control and HD patient fibroblasts. However, HD fibroblasts were delayed in recycling biotin-transferrin back to the plasma membrane. Membranes of HD fibroblasts supported less nucleotide exchange on Rab11 than did control membranes. Rab11-positive vesicular and tubular structures in HD fibroblasts were abnormally large, suggesting that they were impaired in forming vesicles. We used total internal reflection fluorescence imaging of living fibroblasts to monitor fluorescence-labeled transferrin-carrying transport intermediates that emerged from recycling endosomes. HD fibroblasts had fewer small vesicles and more large vesicles and long tubules than did control fibroblasts. Dominant active Rab11 expressed in HD fibroblasts normalized the recycling of biotin-transferrin. We propose a novel mechanism for cellular dysfunction by the HD mutation arising from the inhibition of Rab11 activity and a deficit in vesicle formation at recycling endosomes.
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A dominant-negative mutant of rab5 inhibits infection of cells by foot-and-mouth disease virus: implications for virus entry. J Virol 2009; 83:6247-56. [PMID: 19357169 DOI: 10.1128/jvi.02460-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) can use a number of different integrins (alphavbeta1, alphavbeta3, alphavbeta6, and alphavbeta8) as receptors to initiate infection. Infection mediated by alphavbeta6 is known to occur by clathrin-mediated endocytosis and is dependent on the acidic pH within endosomes. On internalization, virus is detected rapidly in early endosomes (EE) and subsequently in perinuclear recycling endosomes (PNRE), but not in late endosomal compartments. Due to the extreme sensitivity of FMDV to acidic pH, it is thought that EE can provide a pH low enough for infection to occur; however, definitive proof that infection takes place from within these compartments is still lacking. Here we have investigated the intracellular transport steps required for FMDV infection of IBRS-2 cells, which express alphavbeta8 as their FMDV receptor. These experiments confirmed that FMDV infection mediated by alphavbeta8 is also dependent on clathrin-mediate endocytosis and an acidic pH within endosomes. Also, the effect on FMDV infection of dominant-negative (DN) mutants of cellular rab proteins that regulate endosomal traffic was examined. Expression of DN rab5 reduced the number of FMDV-infected cells by 80%, while expression of DN rab4 or DN rab7 had virtually no effect on infection. Expression of DN rab11 inhibited infection by FMDV, albeit to a small extent ( approximately 35%). These results demonstrate that FMDV infection takes place predominantly from within EE and does not require virus trafficking to the late endosomal compartments. However, our results suggest that infection may not be exclusive to EE and that a small amount of infection could occur from within PNRE.
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Ward ES, Ober RJ. Chapter 4: Multitasking by exploitation of intracellular transport functions the many faces of FcRn. Adv Immunol 2009; 103:77-115. [PMID: 19755184 DOI: 10.1016/s0065-2776(09)03004-1] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The MHC Class I-related receptor, FcRn, transports antibodies of the immunoglobulin G (IgG) class within and across a diverse array of different cell types. Through this transport, FcRn serves multiple roles throughout adult life that extend well beyond its earlier defined function of transcytosing IgGs from mother to offspring. These roles include the maintenance of IgG levels and the delivery of antigen in the form of immune complexes to degradative compartments within cells. Recent studies have led to significant advances in knowledge of the intracellular trafficking of FcRn and (engineered) IgGs at both the molecular and cellular levels. The engineering of FcRn-IgG (or Fc) interactions to generate antibodies of increased longevity represents an area of active interest, particularly in the light of the expanding use of antibodies in therapy. The strict pH dependence of FcRn-IgG interactions, with binding at pH 6 that becomes essentially undetectable as near neutral pH is approached, is essential for efficient transport. The requirement for retention of low affinity at near neutral pH increases the complexity of engineering antibodies for increased half-life. Conversely, engineered IgGs that have gained significant binding for FcRn at this pH can be potent inhibitors of FcRn that lower endogenous IgG levels and have multiple potential uses as therapeutics. In addition, molecular studies of FcRn-IgG interactions indicate that mice have limitations as preclinical models for FcRn function, primarily due to cross-species differences in FcRn-binding specificity.
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Affiliation(s)
- E Sally Ward
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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29
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Clustering of endocytic organelles in parental and drug-resistant myeloid leukaemia cell lines lacking centrosomally organised microtubule arrays. Int J Biochem Cell Biol 2008; 40:2240-52. [PMID: 18439867 DOI: 10.1016/j.biocel.2008.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 02/28/2008] [Accepted: 03/01/2008] [Indexed: 11/23/2022]
Abstract
Spatial organisation and trafficking of endocytic organelles in mammalian cells is tightly regulated and dependent on cytoskeletal networks. The dynamics of endocytic pathways is modified in a number of diseases, including cancer, and notably in multidrug resistant (MDR) cells that are refractory to the effects of several anti-cancer agents. These cells often upregulate expression of drug-efflux pumps but this may be synergistic with alternative resistance mechanisms including increased acidification of endocytic organelles that enhances vesicular sequestration of weak-base anti-cancer drugs such as daunorubicin away from their nuclear target. Here, we characterised the distribution of sequestered daunorubicin in commonly used leukaemia cell lines, HL-60, K562, KG1a and the multidrug resistant HL-60/ADR line, and related this to the spatial distribution of their endocytic organelles and microtubule networks. HL-60 and KG1a cells contained microtubule arrays emanating from organising centres, and their endocytic organelles and daunorubicin labelled vesicles were scattered throughout the cytoplasm. HL-60/ADR and K562 cells showed extensive clustering of early and recycling endosomes, late endosomes, lysosomes and daunorubicin to a juxtanuclear region but these cells lacked microtubule arrays. Microtubular organisation within these clustered regions was however, required for spatial tethering of endocytic organelles and the Golgi, as treatment with nocodazole and paclitaxel had major effects on their distribution. HL-60 and HL-60/ADR cells had similar lysosomal pH of <5.0 and overall these findings suggests a general relationship between the absence of microtubule arrays and the propensity of leukaemia cell lines to cluster endocytic organelles and daunorubicin into the juxtanuclear region.
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Fader CM, Sánchez D, Furlán M, Colombo MI. Induction of autophagy promotes fusion of multivesicular bodies with autophagic vacuoles in k562 cells. Traffic 2007; 9:230-50. [PMID: 17999726 DOI: 10.1111/j.1600-0854.2007.00677.x] [Citation(s) in RCA: 342] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Morphological and biochemical studies have shown that autophagosomes fuse with endosomes forming the so-called amphisomes, a prelysosomal hybrid organelle. In the present report, we have analyzed this process in K562 cells, an erythroleukemic cell line that generates multivesicular bodies (MVBs) and releases the internal vesicles known as exosomes into the extracellular medium. We have previously shown that in K562 cells, Rab11 decorates MVBs. Therefore, to study at the molecular level the interaction of MVBs with the autophagic pathway, we have examined by confocal microscopy the fate of MVBs in cells overexpressing green fluorescent protein (GFP)-Rab11 and the autophagosomal protein red fluorescent protein-light chain 3 (LC3). Autophagy inducers such as starvation or rapamycin caused an enlargement of the vacuoles decorated with GFP-Rab11 and a remarkable colocalization with LC3. This convergence was abrogated by a Rab11 dominant negative mutant, indicating that a functional Rab11 is involved in the interaction between MVBs and the autophagic pathway. Interestingly, we presented evidence that autophagy induction caused calcium accumulation in autophagic compartments. Furthermore, the convergence between the endosomal and the autophagic pathways was attenuated by the Ca2+ chelator acetoxymethyl ester (AM) of the calcium chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), indicating that fusion of MVBs with the autophagosome compartment is a calcium-dependent event. In addition, autophagy induction or overexpression of LC3 inhibited exosome release, suggesting that under conditions that stimulates autophagy, MVBs are directed to the autophagic pathway with consequent inhibition in exosome release.
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Affiliation(s)
- Claudio M Fader
- Laboratorio de Biología Celular y Molecular - Instituto de Histología y Embriología (IHEM), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, 5500 Mendoza, Argentina
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31
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Norouziyan F, Shen WC, Hamm-Alvarez SF. Tyrphostin A8 stimulates a novel trafficking pathway of apically endocytosed transferrin through Rab11-enriched compartments in Caco-2 cells. Am J Physiol Cell Physiol 2007; 294:C7-21. [PMID: 17959726 DOI: 10.1152/ajpcell.00372.2006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The potential application of transferrin receptors as delivery vehicles for transport of macromolecular drugs across intestinal epithelial cells is limited by several factors, including the low level of transferrin receptor-mediated transcytosis, particularly in the apical-to-basolateral direction. The GTPase inhibitor, AG10 (tyrphostin A8), has been shown previously to increase the apical-to-basolateral transcytosis of transferrin in Caco-2 cells. However, the mechanism of the increased transcytosis has not been established. In this report, the effect of AG10 on the trafficking of endocytosed transferrin among different endosomal compartments as well as the involvement of Rab11 in the intracellular trafficking of transferrin was investigated. Confocal microscopy studies showed a high level of colocalization of FITC-transferrin with Rab5 and Rab11 in Caco-2 cells pulsed at 16 degrees C and 37 degrees C, which indicated the presence of apically endocytosed FITC-transferrin in early endosomes and apical recycling endosomes at 16 degrees C and 37 degrees C, respectively. The effect of AG10 on the accumulation of transferrin within different endosomal compartment was studied, and an increase in the transcytosis and recycling of internalized (125)I-labeled transferrin, as well as a decrease in cell-associated (125)I-labeled transferrin, was observed in AG10-treated Caco-2 cells pulsed at 37 degrees C for 30 min and chased for 30 min. Moreover, confocal microscopy showed that FITC-transferrin exhibited an increased level of colocalization with Rab11, but not with Rab5, in the presence of AG10. These results suggest an effect of AG10 on the later steps of transferrin receptor trafficking, which are involved in subsequent recycling, and possibly transcytosis, of endocytosed transferrin in Caco-2 cells.
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Affiliation(s)
- Fariba Norouziyan
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90033, USA
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32
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Devergne O, Ghiglione C, Noselli S. The endocytic control of JAK/STAT signalling in Drosophila. J Cell Sci 2007; 120:3457-64. [PMID: 17855388 DOI: 10.1242/jcs.005926] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Domeless (Dome) is an IL-6-related cytokine receptor that activates a conserved JAK/STAT signalling pathway during Drosophila development. Despite good knowledge of the signal transduction pathway in several models, the role of receptor endocytosis in JAK/STAT activation remains poorly understood. Using both in vivo genetic analysis and cell culture assays, we show that ligand binding of Unpaired 1 (Upd1) induces clathrin-dependent endocytosis of receptor-ligand complexes and their subsequent trafficking through the endosomal compartment towards the lysosome. Surprisingly, blocking trafficking in distinct endosomal compartments using mutants affecting either Clathrin heavy chain, rab5, Hrs or deep orange led to an inhibition of the JAK/STAT pathway, whereas this pathway was unchanged when rab11 was affected. This suggests that internalization and trafficking are both required for JAK/STAT activity. The requirement for clathrin-dependent endocytosis to activate JAK/STAT signalling suggests a model in which the signalling `on' state relies not only on ligand binding to the receptor at the cell surface, but also on the recruitment of the complex into endocytic vesicles on their way to lysozomes. Selective activation of the pool of receptors marked for degradation thus provides a way to tightly control JAK/STAT activity.
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Affiliation(s)
- Olivier Devergne
- Institute of Developmental Biology and Cancer, CNRS-UMR 6543, University of Nice Sophia-Antipolis, Parc Valrose 06108 Nice cedex 2, France
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Roland JT, Kenworthy AK, Peranen J, Caplan S, Goldenring JR. Myosin Vb interacts with Rab8a on a tubular network containing EHD1 and EHD3. Mol Biol Cell 2007; 18:2828-37. [PMID: 17507647 PMCID: PMC1949367 DOI: 10.1091/mbc.e07-02-0169] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 04/16/2007] [Accepted: 05/07/2007] [Indexed: 12/20/2022] Open
Abstract
Cells use multiple pathways to internalize and recycle cell surface components. Although Rab11a and Myosin Vb are involved in the recycling of proteins internalized by clathrin-mediated endocytosis, Rab8a has been implicated in nonclathrin-dependent endocytosis and recycling. By yeast two-hybrid assays, we have now demonstrated that Myosin Vb can interact with Rab8a, but not Rab8b. We have confirmed the interaction of Myosin Vb with Rab11a and Rab8a in vivo by using fluorescent resonant energy transfer techniques. Rab8a and Myosin Vb colocalize to a tubular network containing EHD1 and EHD3, which does not contain Rab11a. Myosin Vb tail can cause the accumulation of both Rab11a and Rab8a in collapsed membrane cisternae, whereas dominant-negative Rab11-FIP2(129-512) selectively accumulates Rab11a but not Rab8a. Additionally, dynamic live cell imaging demonstrates distinct pathways for Rab11a and Rab8a vesicle trafficking. These findings indicate that Rab8a and Rab11a define different recycling pathways that both use Myosin Vb.
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Affiliation(s)
| | - Anne K. Kenworthy
- Cell and Developmental Biology, and
- Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-2733
| | - Johan Peranen
- Nashville Veterans Affairs Medical Center, Nashville, TN 37212-2637
| | - Steve Caplan
- Institute of Biotechnology, University of Helsinki, FIN-00014 Helsinki, Finland; and
| | - James R. Goldenring
- Departments of *Surgery
- Cell and Developmental Biology, and
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198
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Prigozhina NL, Waterman-Storer CM. Decreased polarity and increased random motility in PtK1 epithelial cells correlate with inhibition of endosomal recycling. J Cell Sci 2007; 119:3571-82. [PMID: 16931597 DOI: 10.1242/jcs.03066] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Locomoting cells exhibit a constant retrograde flow of plasma membrane proteins from the leading edge towards the cell center, which, when coupled to substrate adhesion, may drive forward cell movement. Here, we aimed to test the hypothesis that, in epithelial cells, these plasma membrane components are delivered via a polarized endo/exocytotic cycle, and that their correct recycling is required for normal migration. To this end, we expressed in PtK1 cells cDNA constructs encoding GDP-restricted (S25N) and GTP-restricted (Q70L) mutants of Rab11b, a small GTPase that has been implicated in the late stage of recycling, where membrane components from the endosomal recycling compartment are transported back to the plasma membrane. Surprisingly, we found that transient expression of the Rab11b mutants in randomly migrating PtK1 cells in small cell islands caused altered cell morphology and actually increased the velocity of cell locomotion. Stable expression of either mutant protein also did not decrease cell migration velocity, but instead affected the directionality of migration in monolayer wound healing assays. We have also tested the effects of other Rab proteins, implicated in endocytic recycling, and discovered a clear correlation between the degree of recycling inhibition and the increase in non-directional cell motility.
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Takahashi M, Murate M, Fukuda M, Sato SB, Ohta A, Kobayashi T. Cholesterol controls lipid endocytosis through Rab11. Mol Biol Cell 2007; 18:2667-77. [PMID: 17475773 PMCID: PMC1924824 DOI: 10.1091/mbc.e06-10-0924] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cellular cholesterol increases when cells reach confluency in Chinese hamster ovary (CHO) cells. We examined the endocytosis of several lipid probes in subconfluent and confluent CHO cells. In subconfluent cells, fluorescent lipid probes including poly(ethylene glycol)derivatized cholesterol, 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3beta-ol, and fluorescent sphingomyelin analogs were internalized to pericentriolar recycling endosomes. This accumulation was not observed in confluent cells. Internalization of fluorescent lactosylceramide was not affected by cell confluency, suggesting that the endocytosis of specific membrane components is affected by cell confluency. The crucial role of cellular cholesterol in cell confluency-dependent endocytosis was suggested by the observation that the fluorescent sphingomyelin was transported to recycling endosomes when cellular cholesterol was depleted in confluent cells. To understand the molecular mechanism(s) of cell confluency- and cholesterol-dependent endocytosis, we examined intracellular distribution of rab small GTPases. Our results indicate that rab11 but not rab4, altered intracellular localization in a cell confluency-associated manner, and this alteration was dependent on cell cholesterol. In addition, the expression of a constitutive active mutant of rab11 changed the endocytic route of lipid probes from early to recycling endosomes. These results thus suggest that cholesterol controls endocytic routes of a subset of membrane lipids through rab11.
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Affiliation(s)
- Miwa Takahashi
- *Frontier Research System
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | - Mitsunori Fukuda
- Fukuda Initiative Research Unit, and
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Miyagi 980-8578, Japan
| | - Satoshi B. Sato
- *Frontier Research System
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan; and
| | - Akinori Ohta
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toshihide Kobayashi
- *Frontier Research System
- Lipid Biology Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
- Institut National de la Santé et de la Recherche Médicale U870, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, University Lyon 1 and Hospices Civils de Lyon, 69621 Villeurbanne, France
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Lapierre LA, Avant KM, Caldwell CM, Ham AJL, Hill S, Williams JA, Smolka AJ, Goldenring JR. Characterization of immunoisolated human gastric parietal cells tubulovesicles: identification of regulators of apical recycling. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1249-62. [PMID: 17255364 DOI: 10.1152/ajpgi.00505.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric parietal cells possess an amplified apical membrane recycling system dedicated to regulated apical recycling of H-K-ATPase. While amplified in parietal cells, apical recycling is critical to polarized secretory processes in most epithelial cells. To clarify putative regulators of apical recycling, we prepared immunoisolated parietal cell H-K-ATPase-containing recycling membranes from human stomachs and analyzed protein contents by tryptic digestion and mass spectrometry. We identified and validated by Western blots many of the proteins previously identified on immunoisolated rabbit tubulovesicles, including Rab11, Rab25, syntaxin 3, secretory carrier membrane proteins (SCAMPs), and vesicle-associated membrane protein (VAMP)2. In addition, we detected several previously unrecognized proteins, including Rab10, VAMP8, syntaxin 7, and syntaxin 12/13. We also identified the K(+) channel component KCNQ1. Immunostaining of human gastric mucosal sections confirmed the presence of each of these proteins in parietal cells and their colocalization with H-K-ATPase on tubulovesicles. To investigate the role of the identified soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins in apical recycling, we transfected them as DsRed2 fusions into an enhanced green fluorescent protein (EGFP)-Rab11a-expressing Madin-Darby canine kidney (MDCK) cell line. Syntaxin 12/13 and VAMP8 caused a collapse of the EGFP-Rab11a compartment, whereas a less dramatic effect was observed in cells transfected with syntaxin 3, syntaxin 7, or VAMP2. The five DsRed2-SNARE chimeras were also transfected into a MDCK cell line overexpressing Rab11-FIP2(129-512). All five of the chimeras were drawn into the collapsed apical recycling system. This study, which represents the first proteomic analysis of an immunoisolated vesicle population from native human tissue, demonstrates the diversity of putative regulators of the apical recycling system.
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Affiliation(s)
- Lynne A Lapierre
- Dept. of Surgery, Vanderbilt Univ. School of Medicine, 4160A MRB III, 465 21st St. S., Nashville, TN 37232-2733, USA
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Westlake CJ, Junutula JR, Simon GC, Pilli M, Prekeris R, Scheller RH, Jackson PK, Eldridge AG. Identification of Rab11 as a small GTPase binding protein for the Evi5 oncogene. Proc Natl Acad Sci U S A 2007; 104:1236-41. [PMID: 17229837 PMCID: PMC1773056 DOI: 10.1073/pnas.0610500104] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Indexed: 01/15/2023] Open
Abstract
The Evi5 oncogene has recently been shown to regulate the stability and accumulation of critical G(1) cell cycle factors including Emi1, an inhibitor of the anaphase-promoting complex/cyclosome, and cyclin A. Sequence analysis of the amino terminus of Evi5 reveals a Tre-2, Bub2, Cdc16 domain, which has been shown to be a binding partner and GTPase-activating protein domain for the Rab family of small Ras-like GTPases. Here we describe the identification of Evi5 as a candidate binding protein for Rab11, a GTPase that regulates intracellular transport and has specific roles in endosome recycling and cytokinesis. By yeast two-hybrid analysis, immunoprecipitation, and Biacore analysis, we demonstrate that Evi5 binds Rab11a and Rab11b in a GTP-dependent manner. However, Evi5 displays no activation of Rab11 GTPase activity in vitro. Evi5 colocalizes with Rab11 in vivo, and overexpression of Rab11 perturbs the localization of Evi5, redistributing it into Rab11-positive recycling endosomes. Interestingly, in vitro binding studies show that Rab11 effector proteins including FIP3 compete with Evi5 for binding to Rab11, suggesting a partitioning between Rab11-Evi5 and Rab11 effector complexes. Indeed, ablation of Evi5 by RNA interference causes a mislocalization of FIP3 at the abscission site during cytokinesis. These data demonstrate that Evi5 is a Rab11 binding protein and that Evi5 may cooperate with Rab11 to coordinate vesicular trafficking, cytokinesis, and cell cycle control independent of GTPase-activating protein function.
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Affiliation(s)
| | | | - Glenn C. Simon
- Department of Cell and Developmental Biology, School of Medicine, University of Colorado Health Sciences Center, Aurora, CO 80045
| | - Manohar Pilli
- *Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080; and
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, School of Medicine, University of Colorado Health Sciences Center, Aurora, CO 80045
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Ameen N, Silvis M, Bradbury NA. Endocytic trafficking of CFTR in health and disease. J Cyst Fibros 2007; 6:1-14. [PMID: 17098482 PMCID: PMC1964799 DOI: 10.1016/j.jcf.2006.09.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 09/19/2006] [Accepted: 09/21/2006] [Indexed: 12/25/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a Cl-selective anion channel expressed in epithelial tissues. Mutations in CFTR lead to the genetic disease cystic fibrosis (CF). Within each epithelial cell, CFTR interacts with a large number of transient macromolecular complexes, many of which are involved in the trafficking and targeting of CFTR. Understanding how these complexes regulate the trafficking and fate of CFTR, provides a singular insight not only into the patho-physiology of cystic fibrosis, but also provides potential drug targets to help cure this debilitating disease.
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Affiliation(s)
- Nadia Ameen
- Department of Paediatrics, University of Pittsburgh School of Medicine
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine
| | - Mark Silvis
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine
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McGurk L, Tzolovsky G, Spears N, Bownes M. The temporal and spatial expression pattern of Myosin Va, Vb and VI in the mouse ovary. Gene Expr Patterns 2006; 6:900-7. [PMID: 16713372 DOI: 10.1016/j.modgep.2006.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 02/23/2006] [Accepted: 03/02/2006] [Indexed: 11/23/2022]
Abstract
There are 16 classes of unconventional myosins. Class V myosins have been shown to be involved in transporting cargo to and from the cell periphery. Class VI myosins have also been shown to transport cargo from the cell periphery, although it seems that these proteins have many roles which include the mediation of cell migration and stereocillia stabilisation. With the requirement of myosin VI for Drosophila oogenesis, the localised expression of Myosin V in the developing egg chamber and recent mounting evidence which links myosin VI to the migration of human ovarian cancer cell lines, we wanted to investigate the expression pattern of these two myosin classes in the normal mouse ovary. Here we show that these myosins are expressed, localised and regulated within the oocyte and granulosa cells of the developing mouse follicle.
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Affiliation(s)
- Leeanne McGurk
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom.
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40
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Pooley RD, Reddy S, Soukoulis V, Roland JT, Goldenring JR, Bader DM. CytLEK1 is a regulator of plasma membrane recycling through its interaction with SNAP-25. Mol Biol Cell 2006; 17:3176-86. [PMID: 16672379 PMCID: PMC1483049 DOI: 10.1091/mbc.e05-12-1127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 04/17/2006] [Accepted: 04/25/2006] [Indexed: 12/26/2022] Open
Abstract
SNAP-25 is a component of the SNARE complex that is involved in membrane docking and fusion. Using a yeast two-hybrid screen, we identify a novel interaction between SNAP-25 and cytoplasmic Lek1 (cytLEK1), a protein previously demonstrated to associate with the microtubule network. The binding domains within each protein were defined by yeast two-hybrid, coimmunoprecipitation, and colocalization studies. Confocal analyses reveal a high degree of colocalization between the proteins. In addition, the endogenous proteins can be isolated as a complex by immunoprecipitation. Further analyses demonstrate that cytLEK1 and SNAP-25 colocalize and coprecipitate with Rab11a, myosin Vb, VAMP2, and syntaxin 4, components of the plasma membrane recycling pathway. Overexpression of the SNAP-25-binding domain of cytLEK1, and depletion of endogenous Lek1 alters transferrin trafficking, consistent with a function in vesicle recycling. Taken together, our studies indicate that cytLEK1 is a link between recycling vesicles and the microtubule network through its association with SNAP-25. This interaction may play a key role in the regulation of the recycling endosome pathway.
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Affiliation(s)
- Ryan D. Pooley
- *Stahlman Cardiovascular Research Laboratories, Program for Developmental Biology, and Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300; and
| | - Samyukta Reddy
- *Stahlman Cardiovascular Research Laboratories, Program for Developmental Biology, and Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300; and
| | - Victor Soukoulis
- *Stahlman Cardiovascular Research Laboratories, Program for Developmental Biology, and Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300; and
| | - Joseph T. Roland
- Department of Surgery and Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, and Nashville VAMC, Nashville, TN 37212-2175
| | - James R. Goldenring
- Department of Surgery and Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, and Nashville VAMC, Nashville, TN 37212-2175
| | - David M. Bader
- *Stahlman Cardiovascular Research Laboratories, Program for Developmental Biology, and Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300; and
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Jin M, Goldenring JR. The Rab11-FIP1/RCP gene codes for multiple protein transcripts related to the plasma membrane recycling system. ACTA ACUST UNITED AC 2006; 1759:281-95. [PMID: 16920206 DOI: 10.1016/j.bbaexp.2006.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Revised: 05/16/2006] [Accepted: 06/08/2006] [Indexed: 01/01/2023]
Abstract
Rab11a is a member of the Rab11 small GTPase family, and plays an important role in plasma membrane recycling. Rab11-Family Interacting Protein 1 (Rab11-FIP1) binds to Rab11 through a carboxyl-terminal amphipathic alpha helix. We have identified eight alternatively spliced Rab11-FIP1 gene transcripts from human chromosome 8. Among them, Rab11-FIP1A-D have carboxyl terminal Rab11 binding domains, while Rab11-FIP1E-H do not contain the Rab11 binding domain. While Rab11-FIP1B and F gene transcripts are ubiquitous, other Rab11-FIP1 transcripts demonstrate more limited patterns of expression in human tissue cDNAs. EGFP-Rab11-FIP1A-D proteins over-expressed in HeLa cells targeted to Rab11a-containing membranes, while EGFP-Rab11-FIP1E/F and H proteins did not localize with recycling system membranes. However, transferrin trafficking was not significantly altered in HeLa cells over-expressing expressing any of the EGFP-Rab11-FIP1 proteins. Rabbit polyclonal antibodies specific for Rab11-FIP1B and Rab11-FIP1C/RCP demonstrated that Rab11-FIP1B and Rab11-FIP1C/RCP are expressed endogenously. Strikingly, endogenous staining for Rab11-FIP1C/RCP only partially co-localized with EGFP-Rab11-FIP1A, EGFP-Rab11-FIP1B, and EGFP-Rab11a in the perinuclear region, indicating that Rab11-FIP1C/RCP resides in a differentiable subcellular compartment within the plasma membrane recycling system compared with Rab11-FIP1A and Rab11-FIP1B. These data suggest that Rab11-FIP1 proteins may play coordinated roles in regulating plasma membrane recycling with regional specificity within the Rab11a-containing recycling system.
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Affiliation(s)
- Min Jin
- Department of Surgery, Vanderbilt University School of Medicine, Vanderbilt-Ingram Cancer Center and the Nashville VA Medical Center, Nashville, TN 37232, USA
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42
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Fader CM, Savina A, Sánchez D, Colombo MI. Exosome secretion and red cell maturation: Exploring molecular components involved in the docking and fusion of multivesicular bodies in K562 cells. Blood Cells Mol Dis 2006; 35:153-7. [PMID: 16099697 DOI: 10.1016/j.bcmd.2005.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 07/06/2005] [Indexed: 12/22/2022]
Abstract
During reticulocyte maturation, some membrane proteins and organelles that are not required in the mature red cell are lost. These proteins are released into the extracellular medium associated with vesicles present in multivesicular bodies (MVBs). Fusion of MVBs with the plasma membrane results in secretion of the small internal vesicles, termed exosomes. By studying MVBs fusion and exosome release in K562 cells, a human erythroleukemic cell line, we have determined the functional significance of Rab11 and calcium in these events. Additionally, in the transformation process that occurs during erythrocyte maturation, intracellular organelles are likely removed as a consequence of autophagic sequestration and degradation. We propose K562 cells as a useful tool to analyze, at the molecular level, the role of autophagy in the terminal differentiation of red cells.
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Affiliation(s)
- Claudio M Fader
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, Centro Universitario, Parque General San Martín, 5500 Mendoza, Argentina
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43
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Chen MC, Hong MC, Huang YS, Liu MC, Cheng YM, Fang LS. ApRab11, a cnidarian homologue of the recycling regulatory protein Rab11, is involved in the establishment and maintenance of the Aiptasia-Symbiodinium endosymbiosis. Biochem Biophys Res Commun 2005; 338:1607-16. [PMID: 16288726 DOI: 10.1016/j.bbrc.2005.10.133] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 10/21/2005] [Indexed: 11/21/2022]
Abstract
Endosymbiotic association of the Symbiodinium dinoflagellates (zooxanthellae) with their cnidarian host cells involves an alteration in the development of the alga-enclosing phagosomes. To uncover its molecular basis, we previously investigated and established that the intracellular persistence of the zooxanthella-containing phagosomes involves specific alga-mediated interference with the expression of ApRab5 and ApRab7, two key endocytic regulatory Rab proteins, which results in the selective retention of the former on and exclusion of the later from the organelles. Here we examined the role of ApRab11, a cnidarian homologue of the key endocytic recycling regulator, Rab11, in the Aiptasia-Symbiodinium endosymbiosis. ApRab11 protein shared 88% overall sequence identity with human Rab11A and contained all Rab-specific signature motifs. Co-localization and mutagenesis studies showed that EGFP-tagged ApRab11 was predominantly associated with recycling endosomes and functioned in the recycling of internalized transferrin. In phagocytosis of latex beads, ApRab11 was quickly recruited to and later gradually removed from the developing phagosomes. Significantly, although ApRab11 immunoreactivity was rapidly detected on the phagosomes containing either newly internalized, heat-killed zooxanthellae, or resident zooxanthellae briefly treated with the photosynthesis inhibitor DCMU, it was rarely observed in the majority of phagosomes containing either newly internalized live, or healthy resident, zooxanthellae. It was concluded that through active exclusion of ApRab11 from the phagosomes in which they reside, zooxanthellae interfere with the normal recycling process required for efficient phagosome maturation, and thereby, secure their intracellular persistence, and consequently their endosymbiotic relationship with their cnidarian hosts.
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Affiliation(s)
- Ming-Chyuan Chen
- Department of Marine Biotechnology, National Kaohsiung Marine University, Kaohsiung 811, Taiwan, ROC
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44
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Murray JL, Mavrakis M, McDonald NJ, Yilla M, Sheng J, Bellini WJ, Zhao L, Le Doux JM, Shaw MW, Luo CC, Lippincott-Schwartz J, Sanchez A, Rubin DH, Hodge TW. Rab9 GTPase is required for replication of human immunodeficiency virus type 1, filoviruses, and measles virus. J Virol 2005; 79:11742-51. [PMID: 16140752 PMCID: PMC1212642 DOI: 10.1128/jvi.79.18.11742-11751.2005] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rab proteins and their effectors facilitate vesicular transport by tethering donor vesicles to their respective target membranes. By using gene trap insertional mutagenesis, we identified Rab9, which mediates late-endosome-to-trans-Golgi-network trafficking, among several candidate host genes whose disruption allowed the survival of Marburg virus-infected cells, suggesting that Rab9 is utilized in Marburg replication. Although Rab9 has not been implicated in human immunodeficiency virus (HIV) replication, previous reports suggested that the late endosome is an initiation site for HIV assembly and that TIP47-dependent trafficking out of the late endosome to the trans-Golgi network facilitates the sorting of HIV Env into virions budding at the plasma membrane. We examined the role of Rab9 in the life cycles of HIV and several unrelated viruses, using small interfering RNA (siRNA) to silence Rab9 expression before viral infection. Silencing Rab9 expression dramatically inhibited HIV replication, as did silencing the host genes encoding TIP47, p40, and PIKfyve, which also facilitate late-endosome-to-trans-Golgi vesicular transport. In addition, silencing studies revealed that HIV replication was dependent on the expression of Rab11A, which mediates trans-Golgi-to-plasma-membrane transport, and that increased HIV Gag was sequestered in a CD63+ endocytic compartment in a cell line stably expressing Rab9 siRNA. Replication of the enveloped Ebola, Marburg, and measles viruses was inhibited with Rab9 siRNA, although the non-enveloped reovirus was insensitive to Rab9 silencing. These results suggest that Rab9 is an important cellular target for inhibiting diverse viruses and help to define a late-endosome-to-plasma-membrane vesicular transport pathway important in viral assembly.
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Affiliation(s)
- James L Murray
- National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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45
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Strick DJ, Elferink LA. Rab15 effector protein: a novel protein for receptor recycling from the endocytic recycling compartment. Mol Biol Cell 2005; 16:5699-709. [PMID: 16195351 PMCID: PMC1289414 DOI: 10.1091/mbc.e05-03-0204] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sorting endosomes and the endocytic recycling compartment are critical intracellular stores for the rapid recycling of internalized membrane receptors to the cell surface in multiple cell types. However, the molecular mechanisms distinguishing fast receptor recycling from sorting endosomes and slow receptor recycling from the endocytic recycling compartment remain poorly understood. We previously reported that Rab15 differentially regulates transferrin receptor trafficking through sorting endosomes and the endocytic recycling compartment, suggesting a role for distinct Rab15-effector interactions at these endocytic compartments. In this study, we identified the novel protein Rab15 effector protein (REP15) as a binding partner for Rab15-GTP. REP15 is compartment specific, colocalizing with Rab15 and Rab11 on the endocytic recycling compartment but not with Rab15, Rab4, or early endosome antigen 1 on sorting endosomes. REP15 interacts directly with Rab15-GTP but not with Rab5 or Rab11. Consistent with its localization, REP15 overexpression and small interfering RNA-mediated depletion inhibited transferrin receptor recycling from the endocytic recycling compartment, without affecting receptor entry into or recycling from sorting endosomes. Our data identify REP15 as a compartment-specific protein for receptor recycling from the endocytic recycling compartment, highlighting that the rapid and slow modes of transferrin receptor recycling are mechanistically distinct pathways.
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Affiliation(s)
- David J Strick
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1043, USA
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46
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Montesinos ML, Castellano-Muñoz M, García-Junco-Clemente P, Fernández-Chacón R. Recycling and EH domain proteins at the synapse. ACTA ACUST UNITED AC 2005; 49:416-28. [PMID: 16054223 DOI: 10.1016/j.brainresrev.2005.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 06/13/2005] [Accepted: 06/14/2005] [Indexed: 11/29/2022]
Abstract
In neurons, a network of endocytic proteins accomplishes highly regulated processes such as synaptic vesicle cycling and the timely internalization of intracellular signaling molecules. In this review, we discuss recent advances on molecular networks created through interactions between proteins bearing the Eps15 homology (EH) domain and partner proteins containing the Asn-Pro-Phe (NPF) motif, which participate in important aspects of neuronal function as the synaptic vesicle cycle, the internalization of nerve growth factor (NGF), the determination of neuronal cell fate, the development of synapses and the trafficking of postsynaptic receptors. We discuss novel functional findings on the role of intersectin and synaptojanin and then we focus on the features of an emerging family of EH domain proteins termed EHDs (EH domain proteins), which are important for endocytic recycling of membrane proteins.
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Affiliation(s)
- María Luz Montesinos
- Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Avda. Sánchez-Pizjuán 4, E-41009 Sevilla, Spain.
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47
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Neel NF, Schutyser E, Sai J, Fan GH, Richmond A. Chemokine receptor internalization and intracellular trafficking. Cytokine Growth Factor Rev 2005; 16:637-58. [PMID: 15998596 PMCID: PMC2668263 DOI: 10.1016/j.cytogfr.2005.05.008] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Accepted: 05/03/2005] [Indexed: 01/25/2023]
Abstract
The internalization and intracellular trafficking of chemokine receptors have important implications for the cellular responses elicited by chemokine receptors. The major pathway by which chemokine receptors internalize is the clathrin-mediated pathway, but some receptors may utilize lipid rafts/caveolae-dependent internalization routes. This review discusses the current knowledge and controversies regarding these two different routes of endocytosis. The functional consequences of internalization and the regulation of chemokine receptor recycling will also be addressed. Modifications of chemokine receptors, such as palmitoylation, ubiquitination, glycosylation, and sulfation, may also impact trafficking, chemotaxis and signaling. Finally, this review will cover the internalization and trafficking of viral and decoy chemokine receptors.
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Affiliation(s)
- Nicole F Neel
- Department of Veterans Affairs Medical Center, Vanderbilt University School of Medicine, 432 PRB, 23rd Avenue South at Pierce, Nashville, TN 37232, USA.
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48
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Ward ES, Martinez C, Vaccaro C, Zhou J, Tang Q, Ober RJ. From sorting endosomes to exocytosis: association of Rab4 and Rab11 GTPases with the Fc receptor, FcRn, during recycling. Mol Biol Cell 2005; 16:2028-38. [PMID: 15689494 PMCID: PMC1073680 DOI: 10.1091/mbc.e04-08-0735] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A longstanding question in cell biology is how is the routing of intracellular organelles within cells regulated? Although data support the involvement of Rab4 and Rab11 GTPases in the recycling pathway, the function of Rab11 in particular is uncertain. Here we have analyzed the association of these two Rab GTPases with the Fc receptor, FcRn, during intracellular trafficking. This Fc receptor is both functionally and structurally distinct from the classical Fcgamma receptors and transports immunoglobulin G (IgG) within cells. FcRn is therefore a recycling receptor that sorts bound IgG from unbound IgG in sorting endosomes. In the current study we have used dual color total internal reflection fluorescence microscopy (TIRFM) and wide-field imaging of live cells to analyze the events in human endothelial cells that are involved in the trafficking of FcRn positive (FcRn(+)) recycling compartments from sorting endosomes to exocytic sites at the plasma membrane. Our data are consistent with the following model for this pathway: FcRn leaves sorting endosomes in Rab4(+)Rab11(+) or Rab11(+) compartments. For Rab4(+)Rab11(+) compartments, Rab4 depletion occurs by segregation of the two Rab proteins into discrete domains that can separate. The Rab11(+)FcRn(+) vesicle or tubule subsequently fuses with the plasma membrane in an exocytic event. In contrast to Rab11, Rab4 is not involved in exocytosis.
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Affiliation(s)
- E Sally Ward
- Center for Immunology, University of Texas Southwestern Medical Center, Dallas, 75390-8576, USA.
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49
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Safaei R, Katano K, Larson BJ, Samimi G, Holzer AK, Naerdemann W, Tomioka M, Goodman M, Howell SB. Intracellular Localization and Trafficking of Fluorescein-Labeled Cisplatin in Human Ovarian Carcinoma Cells. Clin Cancer Res 2005. [DOI: 10.1158/1078-0432.756.11.2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Purpose: We sought to identify the subcellular compartments in which cisplatin [cis-diamminedichloroplatinum (DDP)] accumulates in human ovarian carcinoma cells and define its export pathways.
Experimental Design: Deconvoluting digital microscopy was used to identify the subcellular location of fluorescein-labeled DDP (F-DDP) in 2008 ovarian carcinoma cells stained with organelle-specific markers. Drugs that block vesicle movement were used to map the traffic pattern.
Results: F-DDP accumulated in vesicles and were not detectable in the cytoplasm. F-DDP accumulated in the Golgi, in vesicles belonging to the secretory export pathway, and in lysosomes but not in early endosomes. F-DDP extensively colocalized with vesicles expressing the copper efflux protein, ATP7A, whose expression modulates the cellular pharmacology of DDP. Inhibition of vesicle trafficking with brefeldin A, wortmannin, or H89 increased the F-DDP content of vesicles associated with the pre-Golgi compartments and blocked the loading of F-DDP into vesicles of the secretory pathway. The importance of the secretory pathway was confirmed by showing that wortmannin and H89 increased whole cell accumulation of native DDP.
Conclusions: F-DDP is extensively sequestered into vesicular structures of the lysosomal, Golgi, and secretory compartments. Much of the distribution to other compartments occurs via vesicle trafficking. F-DDP detection in the vesicles of the secretory pathway is consistent with a major role for this pathway in the efflux of F-DDP and DDP from the cell.
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Affiliation(s)
| | | | | | | | | | | | - Mika Tomioka
- 1Medicine, and Departments of
- 2Chemistry, and the Rebecca and John Moores Cancer Center, University of California, San Diego, California
| | - Murray Goodman
- 2Chemistry, and the Rebecca and John Moores Cancer Center, University of California, San Diego, California
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Ducharme NA, Jin M, Lapierre LA, Goldenring JR. Assessment of Rab11‐FIP2 Interacting Proteins In Vitro. Methods Enzymol 2005; 403:706-15. [PMID: 16473632 DOI: 10.1016/s0076-6879(05)03061-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Members of the Rab family of small GTPases are involved in multiple trafficking events in both endocytotic and biosynthetic pathways. To understand more fully the regulation of these events, a concerted effort is underway to ascertain the binding partners and regulators of Rabs. Here, we describe methods to assess binding of Rab11a with Rab11-FIP2 and other Rab11-FIPs utilizing a modified far-Western approach. We then broaden this application to assess binding of Rab11-FIP2 with myosin Vb and homodimerization of Rab11-FIP2.
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