Rab escort protein 1 ( REP 1 ) in intracellular traffic : a functional and pathophysiological overview Markus

requests to: Dr. rer. medic. Markus N. Preising, Dipl.Biol. (PhD) Department of Pediatric Ophthalmology, Strabismology and Ophthalmogenetics Klinikum, University of Regensburg 93042 Regensburg, Germany Tel: +49-941-944-9276 Fax: +49-941-944-9258 E-mail: markus.preising@klinik. uni-regensburg.de Abstract The intracellular distribution of proteins, compartments, substrates, and products is an active process called intracellular traffic. Control of intracellular traffic is established by small GTP-binding proteins (Rab proteins). Rab proteins are modified by geranyl-geranyl moieties necessary for membrane association and target-protein recognition. Geranyl-geranyl groups are transferred to Rab proteins by geranyl-geranyl transferase 2 (GGTase2). GGTase2 requires Rab escort protein 1 (REP1) to bind Rab proteins. REP1 null mutations underlie an X-linked retinal degeneration called choroideremia (CHM). This review summarizes the current biochemical and clinical knowledge on REP1 and CHM.