RUTBC2 protein, a Rab9A effector and GTPase-activating protein for Rab36

TY - JOUR

T1 - RUTBC2 protein, a Rab9A effector and GTPase-activating protein for Rab36

AU - Nottingham, Ryan M.

AU - Pusapati, Ganesh V.

AU - Ganley, Ian G.

AU - Barr, Francis A.

AU - Lambright, David G.

AU - Pfeffer, Suzanne R.

PY - 2012/6/29

Y1 - 2012/6/29

N2 - Rab GTPases regulate vesicle budding, motility, docking, and fusion. In cells, their cycling between active, GTP-bound states and inactive, GDP-bound states is regulated by the action of opposing enzymes called guanine nucleotide exchange factors and GTPase-activating proteins (GAPs). The substrates for most RabGAPs are unknown, and the potential for cross-talk between different membrane trafficking pathways remains uncharted territory. Rab9A and its effectors regulate recycling of mannose 6-phosphate receptors from late endosomes to the trans Golgi network. We show here that RUTBC2 is a TBC domain-containing protein that binds to Rab9A specifically both in vitro and in cultured cells but is not a GAP for Rab9A. Biochemical screening of Rab protein substrates for RUTBC2 revealed highest GAP activity toward Rab34 and Rab36. In cells, membrane-associated RUTBC2 co-localizes with Rab36, and expression of wild type RUTBC2, but not the catalytically inactive, RUTBC2 R829A mutant, decreases the amount of membrane-associated Rab36 protein. These data show that RUTBC2 can act as a Rab36 GAP in cells and suggest that RUTBC2 links Rab9A function to Rab36 function in the endosomal system.

AB - Rab GTPases regulate vesicle budding, motility, docking, and fusion. In cells, their cycling between active, GTP-bound states and inactive, GDP-bound states is regulated by the action of opposing enzymes called guanine nucleotide exchange factors and GTPase-activating proteins (GAPs). The substrates for most RabGAPs are unknown, and the potential for cross-talk between different membrane trafficking pathways remains uncharted territory. Rab9A and its effectors regulate recycling of mannose 6-phosphate receptors from late endosomes to the trans Golgi network. We show here that RUTBC2 is a TBC domain-containing protein that binds to Rab9A specifically both in vitro and in cultured cells but is not a GAP for Rab9A. Biochemical screening of Rab protein substrates for RUTBC2 revealed highest GAP activity toward Rab34 and Rab36. In cells, membrane-associated RUTBC2 co-localizes with Rab36, and expression of wild type RUTBC2, but not the catalytically inactive, RUTBC2 R829A mutant, decreases the amount of membrane-associated Rab36 protein. These data show that RUTBC2 can act as a Rab36 GAP in cells and suggest that RUTBC2 links Rab9A function to Rab36 function in the endosomal system.

UR - https://www.scopus.com/pages/publications/84863312340

U2 - 10.1074/jbc.M112.362558

DO - 10.1074/jbc.M112.362558

M3 - Article

C2 - 22637480

AN - SCOPUS:84863312340

SN - 0021-9258

VL - 287

SP - 22740

EP - 22748

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 27

ER -