RAB31 GEFs exchange GTP for GDP on RAB31

RAB31, also referred to as RAB22B, is a member of the RAB5 family of proteins (Chen et al, 1996; Bao et al, 2002). It is involved in trafficking pathways at the trans-Golgi network (TGN) and early endosome, where it is required for insulin-stimulated GLUT4 transport, internalization of the EGFR receptor and for mannose-6-phosphate receptor transport from the TGN (Rodriguez-Gabin et al, 2001; Lodhi et al, 2007; Chua et al, 2014; Ng et al, 2007; Ng et al, 2009; Rodriguez-Gabin et al, 2009). RAB31 overexpression is also implicated in cellular proliferation and apoptosis during cancer progression (Pan et al, 2015; reviewed in Chua and Tang, 2015). RAB31 is activated by VPS domain-containing GEFs GAPVD1 (also known as GAPEX5 or RAP6) and RIN3 (Hunker et al, 2006; Lodhi et al, 2007; Kajiho et al, 2003; Kajiho et al, 2011). Interaction of RAB31:GDP with its GEFs promotes release of GDP, allowing GTP to bind, and precludes the interaction of RAB31 with GDI and CHM proteins.

RAB31，亦称RAB22B，属于RAB5蛋白家族（Chen等，1996；Bao等，2002）。该蛋白参与跨高尔基网络（TGN）及早期内体中的物质运输途径，对于胰岛素诱导的GLUT4转运、EGFR受体的内吞作用以及从TGN向mannose-6-phosphate受体的运输至关重要（Rodriguez-Gabin等，2001；Lodhi等，2007；Chua等，2014；Ng等，2007；Ng等，2009；Rodriguez-Gabin等，2009）。RAB31的过表达与癌症进展过程中的细胞增殖和凋亡有关（Pan等，2015；详见Chua和Tang，2015年的综述）。RAB31的激活由VPS结构域包含的GEFs GAPVD1（亦称GAPEX5或RAP6）和RIN3介导（Hunker等，2006；Lodhi等，2007；Kajiho等，2003；Kajiho等，2011）。RAB31:GDP与GEFs的相互作用促进GDP的释放，从而允许GTP的结合，并阻止RAB31与GDI和CHM蛋白的相互作用。