Binding of AP-1 Golgi adaptors to membranes requires phosphorylated cytoplasmic domains of the mannose 6-phosphate/insulin-like growth factor II receptor

• Published in: The Journal of biological chemistry 1993-10, Vol.268 (30), p.22552-22556
• Main Authors: Le Borgne, R, Schmidt, A, Mauxion, F, Griffiths, G, Hoflack, B
• Format: Article
• Language: English
• Subjects: Animals; Binding Sites; Binding, Competitive; Biological and medical sciences; Cell Line; Cell Membrane - metabolism; Cell physiology; Clathrin - metabolism; Cytoplasm - metabolism; Fundamental and applied biological sciences. Psychology; Golgi Apparatus - metabolism; Guanosine 5'-O-(3-Thiotriphosphate) - pharmacology; HeLa Cells; Humans; Intracellular Membranes - metabolism; Kidney; Kinetics; Membrane and intracellular transports; Molecular and cellular biology; Phosphorylation; Proto-Oncogene Proteins c-jun - metabolism; Rats; Receptor, IGF Type 2 - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)41565-7

In mammalian cells, clathrin-coated vesicles mediate transport of the lysosomal enzyme receptors from the trans-Golgi network to the endocytic pathway. A critical step of this process is the recruitment of Golgi-specific adaptors onto Golgi membranes for efficient clathrin polymerization. An in vitro assay was used here to quantitate this event in streptolysin-O-permeabilized NRK cells. At 37 degrees C, these interactions are cytosol- and energy-dependent, sensitive to GTP gamma S (guanosine 5'-O-(thiotriphosphate)) and brefeldin A. We report that Golgi-specific adaptor binding is enhanced in mannose 6-phosphate/insulin-like growth factor II (IGF II) receptor-overexpressing cells and reduced in mannose 6-phosphate receptor-deficient cells. Furthermore, adaptor binding is partially inhibited after addition of soluble cytoplasmic domains of the mannose 6-phosphate/IGF II receptor. Almost complete inhibition is only observed when this domain is phosphorylated on serines 2421 and 2492, a major modification acquired during exit of the receptor from the Golgi. These results show that the mannose 6-phosphate/IGF II receptor is part of the components that recruit the Golgi-specific adaptors and that its phosphorylation is an important feature for high affinity interactions with sorting components.