Structural and mechanistic insights into regulation of the retromer coat by TBC1d5.
Retromer is a membrane coat complex that is recruited to endosomes by the small GTPase Rab7 and sorting nexin 3. The timing of this interaction and consequent endosomal dynamics are thought to be regulated by the guanine nucleotide cycle of Rab7. Here we demonstrate that TBC1d5, a GTPase-activating protein (GAP) for Rab7, is a high-affinity ligand of the retromer cargo selective complex VPS26/VPS29/VPS35. The crystal structure of the TBC1d5 GAP domain bound to VPS29 and complementary biochemical and cellular data show that a loop from TBC1d5 binds to a conserved hydrophobic pocket on VPS29 opposite the VPS29-VPS35 interface. Additional data suggest that a distinct loop of the GAP domain may contact VPS35. Loss of TBC1d5 causes defective retromer-dependent trafficking of receptors. Our findings illustrate how retromer recruits a GAP, which is likely to be involved in the timing of Rab7 inactivation leading to membrane uncoating, with important consequences for receptor trafficking.
Key Laboratory of Birth Defects and Related Diseases of Women and Children (Ministry of Education), Department of Paediatrics, West China Second University Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China.|Department of Biophysics, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
Da
D
Jia
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.|Key Laboratory of Biotechnology and Pharmaceutical Engineering, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
Jin-San
JS
Zhang
Key Laboratory of Birth Defects and Related Diseases of Women and Children (Ministry of Education), Department of Paediatrics, West China Second University Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China.
Fang
F
Li
Key Laboratory of Birth Defects and Related Diseases of Women and Children (Ministry of Education), Department of Paediatrics, West China Second University Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China.
Jing
J
Wang
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.|Department of Pathophysiology, Qiqihar Medical University, Qiqihar 161006, China.
Zhihui
Z
Deng
Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
Mark A
MA
White
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
Douglas G
DG
Osborne
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
Christine
C
Phillips-Krawczak
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
Timothy S
TS
Gomez
Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Haiying
H
Li
Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Amika
A
Singla
Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas 75390, USA.|Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Ezra
E
Burstein
Departments of Immunology, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
Daniel D
DD
Billadeau
Department of Biophysics, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.|Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Michael K
MK
Rosen
D018360:Crystallography, X-Ray; D011992:Endosomes / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D021381:Protein Transport; D033921:Vesicular Transport Proteins / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D020690:GTPase-Activating Proteins; C543487:TBC1D5 protein, human; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins