title: Vps34 regulates Rab7 and late endocytic trafficking through recruitment of the GTPase-activating protein Armus.
abstract: The class III phosphoinositide 3-kinase (PI3K) Vps34 (also known as PIK3C3 in mammals) produces phosphatidylinositol 3-phosphate [PI(3)P] on both early and late endosome membranes to control membrane dynamics. We used Vps34-deficient cells to delineate whether Vps34 has additional roles in endocytic trafficking. In Vps34-/-mouse embryonic fibroblasts (MEFs), transferrin recycling and EEA1 membrane localization were unaffected despite elevated Rab5-GTP levels. Strikingly, a large increase in Rab7-GTP levels, an accumulation of enlarged late endosomes, and decreased EGFR degradation were observed in Vps34-deficient cells. The hyperactivation of Rab7 in Vps34-deficient cells stemmed from the failure to recruit the Rab7 GTPase-activating protein (GAP) Armus (also known as TBC1D2), which binds to PI(3)P, to late endosomes. Protein-lipid overlay and liposome-binding assays reveal that the putative pleckstrin homology (PH) domain in Armus can directly bind to PI(3)P. Elevated Rab7-GTP led to the failure of intraluminal vesicle (ILV) formation and lysosomal maturation. Rab7 silencing and Armus overexpression alleviated the vacuolization seen in Vps34-deficient cells. Taken together, these results demonstrate that Vps34 has a previously unknown role in regulating Rab7 activity and late endosomal trafficking.
authors: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY11794, USA.
authors: Nadia
authors: N
authors: Jaber
authors: Molecular Medicine, NHLI, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
authors: Noor
authors: N
authors: Mohd-Naim
authors: Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
authors: Ziqing
authors: Z
authors: Wang
authors: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY11794, USA.
authors: Jennifer L
authors: JL
authors: DeLeon
authors: Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA.
authors: Seong
authors: S
authors: Kim
authors: Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, 164 Frelinghuysen Road, Piscataway NJ08854, USA.
authors: Hua
authors: H
authors: Zhong
authors: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY11794, USA.
authors: Namratha
authors: N
authors: Sheshadri
authors: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY11794, USA.
authors: Zhixun
authors: Z
authors: Dou
authors: Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA.
authors: Aimee L
authors: AL
authors: Edinger
authors: Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
authors: Guangwei
authors: G
authors: Du
authors: Molecular Medicine, NHLI, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
authors: Vania M M
authors: VM
authors: Braga
authors: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY11794, USA weixing.zong@pharmacy.rutgers.edu.|Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, 164 Frelinghuysen Road, Piscataway NJ08854, USA.|Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick NJ08903, USA.
authors: Wei-Xing
authors: 0000-0002-3129-8220
authors: WX
authors: Zong
mesh_terms: D000818:Animals; D001343:Autophagy; D055162:Biocatalysis; D058546:Class III Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism / Q000648:ultrastructure; D018345:Mice, Knockout; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D021381:Protein Transport; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism / Q000648:ultrastructure; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000090802:rab7 GTP-Binding Proteins
chemical_list: D020690:GTPase-Activating Proteins; D018129:Phosphatidylinositol Phosphates; C000602313:TBC1D2 protein, mouse; C055525:phosphatidylinositol 3-phosphate; D000090802:rab7 GTP-Binding Proteins; C000716463:rab7 GTP-binding proteins, human; C000716465:rab7 GTP-binding proteins, mouse; D058546:Class III Phosphatidylinositol 3-Kinases; D058570:TOR Serine-Threonine Kinases; D020691:rab GTP-Binding Proteins
keywords: Armus; Endocytosis; Rab7; Vps34