title: Phosphorylation/dephosphorylation of the beta light chain of clathrin from rat liver coated vesicles.
abstract: The phosphorylation in vitro, on serine residues by endogenous casein kinase 2, of the clathrin beta light chain (33 kDa) of rat liver coated vesicles requires the presence of poly(L-lysine) which acts through binding to the beta light chain. The phosphorylation of other proteins is also increased in the presence of poly(L-lysine) and casein kinase 2. In contrast, the phosphorylation of the upper band of the 50-kDa protein doublet from rat liver coated vesicles is inhibited. Rat liver coated vesicles display a protein phosphatase activity which preferentially dephosphorylates clathrin beta light chain. This activity is different from the protein phosphatase which dephosphorylates the 50-kDa protein. This enzyme seems to be unrelated to the ATP/Mg-dependent protein phosphatase, or the polycation-stimulated protein phosphatases, which dephosphorylate the 50-kDa protein and beta light chain very efficiently, but with a different specificity. After dissociation of coated vesicles the beta-light-chain phosphatase activity is recovered in the membrane fraction. This phosphatase activity is inhibited by 50 microM orthovanadate and 5 mM p-nitrophenyl phosphate but not by 10 mM EDTA.
authors.affiliation: Laboratoire de Biochimie des Régulations, Institut de Recherche Scientifique sur le Cancer, Villejuif, France.
authors.forename: J E
authors.initials: JE
authors.lastname: Loeb
authors.forename: B
authors.initials: B
authors.lastname: Cantournet
authors.forename: J P
authors.initials: JP
authors.lastname: Vartanian
authors.forename: J
authors.initials: J
authors.lastname: Goris
authors.forename: W
authors.initials: W
authors.lastname: Merlevede
mesh_terms: D000818:Animals; D047388:Casein Kinases; D002458:Cell Fractionation; D002966:Clathrin / Q000378:metabolism*; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011107:Polylysine / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats
chemical_list: D002966:Clathrin; D047428:Protein Kinase Inhibitors; D011107:Polylysine; D011494:Protein Kinases; D047388:Casein Kinases; D010749:Phosphoprotein Phosphatases