Interorganellar regulation of lysosome positioning by the Golgi apparatus through Rab34 interaction with Rab-interacting lysosomal protein.

We present evidence to suggest the existence of a regulatory pathway for the Golgi apparatus to modulate the spatial positioning of otherwise distantly located lysosomes. Rab34, a new member of the Rab GTPase family, is associated primarily with the Golgi apparatus. Expression of wild-type or GTP-restricted but not GDP-restricted versions of Rab34 causes spatial redistribution of lysosomes from the periphery to the peri-Golgi region. The regulation of lysosomal positioning by Rab34 depends on its association with the membrane mediated by prenylation and its direct interaction with Rab-interacting lysosomal protein (RILP). This biological activity, mediated by Rab34-RILP interaction, is dependent on Lys82 in the switch I region. Our results have uncovered a novel mechanism for the Golgi apparatus to regulate the spatial distribution of another organelle.