Rab7: role of its protein interaction cascades in endo-lysosomal traffic.

Protein-protein interaction cascades are crucial for cellular signaling pathways and cell morphogenesis. Membrane traffic along the secretory and endocytic pathways is similarly governed by regulated protein-protein interactions of diverse machineries, which are inter-regulated, assembled and disassembled sequentially to drive membrane budding, vesicle transport, membrane fission and fusion. Rab7, the key regulator in endo-lysosomal trafficking investigated extensively in the past decades, is emerging to govern early-to-late endosomal maturation, microtubule minus-end as well as plus-end directed endosomal migration and positioning, and endosome-lysosome transport through different protein-protein interaction cascades. We summarize here the key protein interaction cascades of Rab7 by focusing on endo-lysosomal trafficking regulated by its interaction with HOPs, RILP, ORP1L, FYCO1 and Mon1/Sand1-CCZ1 complex.