Multiple Signaling Regulate Tyrosine Ser 31, and Ser 4~ Pathways in Hydroxylase Bovine Chromaffin Cells Phosphorylation at Ser a9,

Intact bovine adrenal medullary chromaffin cells were preincubated with 32poa, and the multiplesite phosphorylation of tyrosine hydroxylase (TH) was studied. Up to eight 32p-labeled peptides were produced by tryptic hydrolysis of TH; however, all of the tryptic phosphopeptides were derived from four phosphorylation sites--Ser ~, Ser 19, Se? 1 and Ser 4~ In situ regulation of 32p incorporation into…