title: Skp2-Mediated RagA Ubiquitination Elicits a Negative Feedback to Prevent Amino-Acid-Dependent mTORC1 Hyperactivation by Recruiting GATOR1.
abstract: The regulation of RagA(GTP) is important for amino-acid-induced mTORC1 activation. Although GATOR1 complex has been identified as a negative regulator for mTORC1 by hydrolyzing RagA(GTP), how GATOR1 is recruited to RagA to attenuate mTORC1 signaling remains unclear. Moreover, how mTORC1 signaling is terminated upon amino acid stimulation is also unknown. We show that the recruitment of GATOR1 to RagA is induced by amino acids in an mTORC1-dependent manner. Skp2 E3 ligase drives K63-linked ubiquitination of RagA, which facilitates GATOR1 recruitment and RagA(GTP) hydrolysis, thereby providing a negative feedback loop to attenuate mTORC1 lysosomal recruitment and prevent mTORC1 hyperactivation. We further demonstrate that Skp2 promotes autophagy but inhibits cell size and cilia growth through RagA ubiquitination and mTORC1 inhibition. We thereby propose a negative feedback whereby Skp2-mediated RagA ubiquitination recruits GATOR1 to restrict mTORC1 signaling upon sustained amino acid stimulation, which serves a critical mechanism to maintain proper cellular functions.
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Jin
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
authors.forename: Szu-Wei
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cai
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Ping-Chieh
authors.initials: PC
authors.lastname: Chou
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Abdol Hossein
authors.initials: AH
authors.lastname: Rezaeian
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Chi-Yun
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Juo-Chin
authors.initials: JC
authors.lastname: Yao
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Gong
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Chia-Hsin
authors.initials: CH
authors.lastname: Chan
authors.affiliation: Department of Biotechnology, Asia University, Taichung 41354, Taiwan.
authors.forename: Chih-Yang
authors.initials: CY
authors.lastname: Huang
authors.affiliation: College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan; Department of Medical Genetics, Pediatrics and Medical Research, China Medical University Hospital, Taichung 40402, Taiwan.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.affiliation: Department of Biotechnology, Asia University, Taichung 41354, Taiwan; Center of Molecular Medicine, China Medical University Hospital, Taichung 40402, Taiwan.
authors.forename: Chang-Hai
authors.initials: CH
authors.lastname: Tsai
authors.affiliation: Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei 10031, Taiwan.
authors.forename: Shih-Hsin
authors.initials: SH
authors.lastname: Tu
authors.affiliation: Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei 10031, Taiwan; Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei 10031, Taiwan.
authors.forename: Chih-Hsiung
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
authors.forename: Dos D
authors.initials: dos D
authors.lastname: Sarbassov
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 10031, Taiwan; School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei 10031, Taiwan; Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 10031, Taiwan; Comprehensive Cancer Center of Taipei Medical University, Taipei 10031, Taiwan.
authors.forename: Yuan-Soon
authors.initials: YS
authors.lastname: Ho
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA; Graduate Institute of Basic Medical Science, China Medical University, Taichung 40402, Taiwan; Department of Biotechnology, Asia University, Taichung 41354, Taiwan. Electronic address: hklin@mdanderson.org.
authors.forename: Hui-Kuan
authors.initials: HK
authors.lastname: Lin
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001343:Autophagy / Q000235:genetics; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D025461:Feedback, Physiological / Q000187:drug effects; D006160:Guanosine Triphosphate / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D008239:Lysine / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D008954:Models, Biological; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism*; D041681:NIH 3T3 Cells; D011485:Protein Binding / Q000187:drug effects; D034622:RNA Interference; D044786:S-Phase Kinase-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D000596:Amino Acids; D046912:Multiprotein Complexes; D044786:S-Phase Kinase-Associated Proteins; D006160:Guanosine Triphosphate; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; C484342:RRAGA protein, human; D020559:Monomeric GTP-Binding Proteins; D008239:Lysine