The cytoplasmic tail of the cation-independent mannose 6-phosphate receptor contains four binding sites for AP-l

摘要

The trafficking of the cation-independent mannose 6-phosphate receptor between the trans-Golgi network and endosorrtes requires binding of sorting determinants in the cytoplasmic tail of the receptor to adaptor protein complex-1 (AP-1). Using a GST pull-down binding assay. four binding motifs were identified in the cytoplasmic tail: a tyrosine-based motif ((YSKV29)-Y-26), an internal dileucine-based motif ((ETEWLM44)-E-39), and two casein kinase 2 sites ((DSEDE88)-D-84 and (DDSDED159)-D-154). The YSKV motif mediated the strongest interaction with AP-1 and the two CK2 motifs bound AP-1 only when they were phosphorylated. The COOH-terminal dileucines were not required for interaction with AP-1. (C) 2004 Elsevier Inc. All rights reserved.