PMID- 24404161 OWN - NLM STAT- MEDLINE DCOM- 20140916 LR - 20240210 IS - 1932-6203 (Electronic) IS - 1932-6203 (Linking) VI - 9 IP - 1 DP - 2014 TI - HRES-1/Rab4 promotes the formation of LC3(+) autophagosomes and the accumulation of mitochondria during autophagy. PG - e84392 LID - 10.1371/journal.pone.0084392 [doi] LID - e84392 AB - HRES-1/Rab4 is a small GTPase that regulates endocytic recycling. It has been colocalized to mitochondria and the mechanistic target of rapamycin (mTOR), a suppressor of autophagy. Since the autophagosomal membrane component microtubule-associated protein light chain 3 (LC3) is derived from mitochondria, we investigated the impact of HRES-1/Rab4 on the formation of LC3(+) autophagosomes, their colocalization with HRES-1/Rab4 and mitochondria, and the retention of mitochondria during autophagy induced by starvation and rapamycin. HRES-1/Rab4 exhibited minimal baseline colocalization with LC3, which was enhanced 22-fold upon starvation or 6-fold upon rapamycin treatment. Colocalization of HRES-1/Rab4 with mitochondria was increased >2-fold by starvation or rapamycin. HRES-1/Rab4 overexpression promoted the colocalization of mitochondria with LC3 upon starvation or rapamycin treatment. A dominant-negative mutant, HRES-1/Rab4(S27N) had reduced colocalization with LC3 and mitochondria upon starvation but not rapamycin treatment. A constitutively active mutant, HRES-1/Rab4(Q72L) showed diminished colocalization with LC3 but promoted the partitioning of mitochondria with LC3 upon starvation or rapamycin treatment. Phosphorylation-resistant mutant HRES-1/Rab4(S204Q) showed diminished colocalization with LC3 but increased partitioning to mitochondria. A newly discovered C-terminally truncated native isoform, HRES-1/Rab4(1-121), showed enhanced localization to LC3 and mitochondria without starvation or rapamycin treatment. HRES-1/Rab4(1-121) increased the formation of LC3(+) autophagosomes in resting cells, while other isoforms promoted autophagosome formation upon starvation. HRES-1/Rab4, HRES-1/Rab4(1-121), HRES-1/Rab4(Q72L) and HRES-1/Rab4(S204Q) promoted the accumulation of mitochondria during starvation. The specificity of HRES-1/Rab4-mediated mitochondrial accumulation is indicated by its abrogation by dominant-negative HRES-1/Rab4(S27N) mutation. The formation of interconnected mitochondrial tubular networks was markedly enhanced by HRES-1/Rab4(Q72L) upon starvation, which may contribute to the retention of mitochondria during autophagy. The present study thus indicates that HRES-1/Rab4 regulates autophagy through promoting the formation of LC3(+) autophagosomes and the preservation of mitochondria. FAU - Talaber, Gergely AU - Talaber G AD - Departments of Medicine, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. FAU - Miklossy, Gabriella AU - Miklossy G AD - Departments of Medicine, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. FAU - Oaks, Zachary AU - Oaks Z AD - Departments of Medicine, State University of New York, Upstate Medical University, Syracuse, New York, United States of America ; Biochemistry and Molecular Biology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. FAU - Liu, Yuxin AU - Liu Y AD - Departments of Medicine, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. FAU - Tooze, Sharon A AU - Tooze SA AD - Cancer Research UK London Research Institute, London, England, United Kingdom. FAU - Chudakov, Dmitriy M AU - Chudakov DM AD - Shemiakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia. FAU - Banki, Katalin AU - Banki K AD - Department of Pathology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. FAU - Perl, Andras AU - Perl A AD - Departments of Medicine, State University of New York, Upstate Medical University, Syracuse, New York, United States of America ; Biochemistry and Molecular Biology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America ; Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America. LA - eng GR - AI048079/AI/NIAID NIH HHS/United States GR - AI072648/AI/NIAID NIH HHS/United States GR - 15153/CRUK_/Cancer Research UK/United Kingdom GR - R56 AI048079/AI/NIAID NIH HHS/United States GR - R01 AI048079/AI/NIAID NIH HHS/United States GR - R01 AI072648/AI/NIAID NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20140103 PL - United States TA - PLoS One JT - PloS one JID - 101285081 RN - 0 (MAP1LC3A protein, human) RN - 0 (Macrolides) RN - 0 (Microtubule-Associated Proteins) RN - 88899-55-2 (bafilomycin A1) RN - EC 3.6.5.2 (rab4 GTP-Binding Proteins) SB - IM MH - Amino Acid Sequence MH - Autophagy/*physiology MH - Cell Line MH - Gene Expression MH - Genes, Reporter MH - Humans MH - Intracellular Membranes/metabolism MH - Macrolides/pharmacology MH - Microtubule-Associated Proteins/chemistry/genetics/*metabolism MH - Mitochondria/drug effects/*metabolism MH - Molecular Sequence Data MH - Phagosomes/*metabolism MH - Protein Binding MH - Protein Transport/drug effects MH - rab4 GTP-Binding Proteins/genetics/*metabolism PMC - PMC3880286 COIS- Competing Interests: The authors have declared that no competing interests exist. EDAT- 2014/01/10 06:00 MHDA- 2014/09/17 06:00 PMCR- 2014/01/03 CRDT- 2014/01/10 06:00 PHST- 2013/09/26 00:00 [received] PHST- 2013/11/22 00:00 [accepted] PHST- 2014/01/10 06:00 [entrez] PHST- 2014/01/10 06:00 [pubmed] PHST- 2014/09/17 06:00 [medline] PHST- 2014/01/03 00:00 [pmc-release] AID - PONE-D-13-39514 [pii] AID - 10.1371/journal.pone.0084392 [doi] PST - epublish SO - PLoS One. 2014 Jan 3;9(1):e84392. doi: 10.1371/journal.pone.0084392. eCollection 2014.