Asymmetric Tethering of Flat and Curved Lipid Membranes by a Golgin

Abstract

Golgins, long stringlike proteins, tether cisternae and transport vesicles at the Golgi apparatus. We examined the attachment of golgin GMAP-210 to lipid membranes. GMAP-210 connected highly curved liposomes to flatter ones. This asymmetric tethering relied on motifs that sensed membrane curvature both in the N terminus of GMAP-210 and in ArfGAP1, which controlled the interaction of the C terminus of GMAP-210 with the small guanine nucleotide–binding protein Arf1. Because membrane curvature constantly changes during vesicular trafficking, this mode of tethering suggests a way to maintain the Golgi architecture without compromising membrane flow.