Microtubule-associated protein kinase-2 phosphorylates and activates tyrosine hydroxylase following depolarization of bovine adrenal chromaffin cells

S. Mitchell Halloran, Philip R Vulliet

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Depolarization of cultured bovine adrenal chromaffin cells with KCl increased the activity of a proline-directed protein kinase that phosphorylates tyrosine hydroxylase. Characterization of the KCl-activated protein kinase activity revealed that it shared similar biochemical and chromatographic properties with the microtubule-associated protein-2 kinase/extracellularly regulated kinase (MAP/ERK) family of protein kinases. This protein kinase activity was found to elute from Mono Q, Superose, and phenyl-Sepharose columns under conditions described for MAP/ERK kinases, and active fractions were found to react with specific antibodies directed against ERKs. The KCl-activated protein kinase was found to phosphorylate the serine 31 site of endogenous bovine adrenal tyrosine hydroxylase. This phosphorylation resulted in an approximately 2-fold activation of tyrosine hydroxylase.

Original languageEnglish (US)
Pages (from-to)30960-30965
Number of pages6
JournalJournal of Biological Chemistry
Issue number49
StatePublished - Dec 9 1994


ASJC Scopus subject areas

  • Biochemistry

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