| ALS2CL , the novel protein highly homologous to the carboxy terminal half of ALS 2 , binds to Rab 5 and modulates endosome dynamics . ^^^ ALS2CL exhibited a specific but a relatively weak Rab 5 GEF activity with accompanying rather strong Rab 5 binding properties . ^^^ These results suggest that ALS2CL is a novel factor modulating the Rab 5 mediated endosome dynamics in the cells . . ^^^ In HeLa cells , co expression of ALS2CL and Rab5A resulted in a unique tubulation phenotype of endosome compartments with significant colocalization of ALS2CL and Rab5A . ^^^ |