The present invention provides inventive polypeptides comprising a C terminal RAB binding domain (RabBD) of RAB family interacting proteins (FIPs) stabilized by peptide stapling, and pharmaceutical compositions thereof. Also provided are methods for modulating RAB function comprising contacting an inventive stapled polypeptide with a RAB protein, and methods of treatment associated with modulation of RAB activity. The present invention also provides methods of making the inventive stapled polypeptides by ring closing metathesis of unstapled polypeptide precursors.