Rabs grab motors: defining the connections between Rab GTPases and motor proteins.

Rab GTPases and their effectors regulate membrane traffic by determining, along with cognate SNAREs, the specificity of transport vesicle docking and fusion steps. Recent studies have also implicated Rabs in the movement of these transport vesicles from their site of formation to their site of fusion, and several Rabs have been linked to specific microtubule- or actin-based motor proteins. Analyses of Rab and motor protein mutants, coupled with advanced imaging techniques, have led to the suggestion that certain Rabs function as essential components of the vesicle receptor for specific motor proteins.