Novel regulatory role of phosphorylated clathrin light chain beta in bovine brain coated vesicles.
The 50-kilodalton (kDa) assembly polypeptide of bovine brain clathrin coated vesicles (CCVs) is phosphorylated in a cyclic nucleotide- and Ca2+-independent manner and is dephosphorylated by a Mg2+-ATP-dependent CCV phosphatase. This report provides evidence for modulation of the phosphorylation reaction of the 50-kDa assembly polypeptide by phosphorylated clathrin light chain beta (pLC beta). In vitro, phosphorylated LC beta inhibits phosphorylation of the 50-kDa polypeptide in CCVs. Furthermore, incubation of previously phosphorylated 50-kDa polypeptide in CCVs with phosphorylated LC beta results in a rapid dephosphorylation of the 50-kDa assembly polypeptide. Both phenomena are time and concentration dependent. Monoclonal antibodies to LC beta prevent the modulatory effect of phosphorylated LC beta on the 50-kDa assembly polypeptide phosphorylation in CCVs. The results obtained indicate for the first time, to our knowledge, that phosphorylated LC beta has a modulatory role in CCVs. The data also suggest that phosphorylated LC beta promotes activation of a coated vesicle phosphatase.
Hanson
V G
VG
Department of Pathology, Mount Sinai School of Medicine, City University of New York, New York 10029.
Schook
W J
WJ
Puszkin
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D002966:Clathrin / Q000302:isolation & purification / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D006706:Homeostasis; D046911:Macromolecular Substances; D008274:Magnesium / Q000378:metabolism; D008970:Molecular Weight; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation
D002966:Clathrin; D046911:Macromolecular Substances; D000255:Adenosine Triphosphate; D010749:Phosphoprotein Phosphatases; D008274:Magnesium