| When coexpressed in transfected 293T cells , rab 8 and the rab8ip / GC kinase formed a complex that could be recovered by immunoprecipitation with antibodies to rab 8 . ^^^ In light of recent evidence that rab proteins may act by promoting the stabilization of SNARE complexes , the specific GTP dependent association of rab 8 with the rab8ip / GC kinase raises the possibility that rab regulated protein phosphorylation is important for vesicle targeting or fusion . ^^^ Here we report the identification and the complete cDNA derived amino acid sequence of a murine rab 8 interacting protein ( rab8ip ) that specifically interacts with rab 8 in a GTP dependent manner . ^^^ Cell fractionation and immunofluorescence analyses indicate that in MDCK cells endogenous rab8ip is present both in the cytosol and as a peripheral membrane protein concentrated in the Golgi region and basolateral plasma membrane domains , sites where rab 8 itself is also located . ^^^ |