The sorLA cytoplasmic domain interacts with GGA1 and-2 and defines minimum requirements for GGA binding

We report that the Vps10p domain receptor sorLA binds the adaptor proteins GGA1 and -2, which take part in Golgi-endosome sorting. The GGAs bind with differential requirements via three critical residues in the C-terminal segment of the sorLA cytoplasmic tail. Unlike in sortilin and the mannose 6-phosphate receptors, the GGA-binding segment in sorLA contains neither an acidic cluster nor a dileucine. Our results support the concept of sorLA as a potential sorting receptor and suggest that key residues in sorLA and sortilin conform to a new type of motif (Psi-Psi-X-X-O) defining minimum requirements for GGA binding to cytoplasmic receptor domains. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.