Analysis of 100-180-kDa phosphoproteins in clathrin-coated vesicles from bovine brain.
Protein kinases which co-purify with clathrin-coated vesicles are known to phosphorylate in vitro the 50-kDa subunit of the HA-II adaptor complex and upon inclusion of polylysine the beta-light chain of clathrin and polypeptides above 100 kDa. Here we relate the high molecular mass phosphoproteins to the known subunits of the adaptor protein complexes and to other clathrin-associated proteins by means of immunoprecipitation with monoclonal antibodies, two-dimensional electrophoresis, or electrophoresis in urea-sodium dodecyl sulfate-polyacrylamide gels. Our results show that some of the labeling of the 100-120-kDa region is accounted for by the beta'- and gamma-subunits of the HA-I adaptor complex, the alpha a-, and, to a lesser extent, by the beta-subunits of the HA-II adaptor complex. In addition, we found the assembly protein AP 180 and a hitherto undescribed 110-kDa coat polypeptide to be heavily phosphorylated upon release of these proteins from the coated vesicle membrane. In all cases, labeling was confined to serine residues.
Morris
S A
SA
Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany.
Mann
A
A
Ungewickell
E
E
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D001923:Brain Chemistry; D002417:Cattle; D002845:Chromatography; D003034:Coated Pits, Cell-Membrane / Q000032:analysis* / Q000648:ultrastructure; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D011992:Endosomes / Q000032:analysis*; D006882:Hydroxyapatites; D046911:Macromolecular Substances; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000302:isolation & purification; D010750:Phosphoproteins / Q000302:isolation & purification*; D010766:Phosphorylation
D000596:Amino Acids; D006882:Hydroxyapatites; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D017886:Durapatite