Microtubule-associated protein kinase-2 phosphorylates and activates tyrosine hydroxylase following depolarization of bovine adrenal chromaffin cells.
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.
Halloran
S M
SM
Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 95616.
Vulliet
P R
PR
D000313:Adrenal Medulla / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004789:Enzyme Activation; D008564:Membrane Potentials / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011189:Potassium Chloride / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D011189:Potassium Chloride; D014446:Tyrosine 3-Monooxygenase; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1