A Steric Gating Mechanism Dictates the Substrate Specificity of a Rab-GEF (Developmental Cell)

Thomas et al. show that certain Rabs are recognized by their guanine nucleotide exchange factors in part through the Rab C-terminal hypervariable domain (HVD). This suggests a model in which the HVD contributes to Rab localization by mediating Rab activation at target organelles.