Regulation of tyrosine hydroxylase by stress‐activated protein kinases

Abstract

Recombinant human tyrosine hydroxylase (hTH1) was found to be phosphorylated by mitogen and stress-activated protein kinase 1 (MSK1) at Ser40 and by p38 regulated/activated kinase (PRAK) on Ser19. Phosphorylation by MSK1 induced an increase in V max and a decrease in K m for 6-(R)-5,6,7,8-tetrahydrobiopterin (BH 4 ), while these kinetic parameters were unaffected as a result of phosphorylation by PRAK. Phosphorylation of both Ser40 and Ser19 induced a high-affinity binding of 14-3-3 proteins, but only the interaction of 14-3-3 with Ser19 increased the hTH1 activity. The 14-3-3 proteins also inhibited the rate of dephosphorylation of Ser19 and Ser40 by 82 and 36%, respectively. The phosphorylation of hTH1 on Ser19 caused a threefold increase in the rate of phosphorylation of Ser40. These studies provide new insights into the possible roles of stress-activated protein kinases in the regulation of catecholamine biosynthesis.

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

“…The 43-residue N-terminal region of TH was used in this work to investigate determinants for binding of this functional domain to membranes and 14-3-3 proteins. Comparison of the K d /S 0.5 values for the interaction of full-length hTH1 with either 14-3-3 proteins (17,48) or membranes (29) with those obtained in this work with the TH-(1-43) and THp-(1-43) peptides suggests that the main determinants for the interactions are included in this N-terminal domain. The TH-derived peptides are thus valuable to reveal the binding specificities.…”

“…The additional sequences in TH and TPH2 (Fig. 1), which include the phosphorylation-targeted Ser 19 (17,19), most probably constitute functional domains in the neuronal hydroxylases, as recently suggested for the N-terminal sequence in TPH2 (59). The 43-residue N-terminal region of TH was used in this work to investigate determinants for binding of this functional domain to membranes and 14-3-3 proteins.…”

“…Phosphorylation of hTH1 at Ser 19 by p38 regulated/activated protein kinase (PRAK) was performed as previously described (17), obtaining a stoichiometry of 0.8 phosphate incorporated/subunit of hTH1.…”

“…For a review, see Ref. 14. Phosphorylation at Ser 19 by either Ca 2ϩ / calmodulin-dependent kinase II, mitogen-activated protein kinase-activated protein kinase 2 (15,16), or p38-regulated/ activated kinase (17) promotes the high affinity binding to 14-3-3 proteins, which increases TH activity severalfold (17,18). TPH2 also binds to 14-3-3 proteins through phosphorylated Ser 19 (19), but little is known about the structural details of the interaction between TH (or TPH2) and 14-3-3, although crystal structures of all 14-3-3 isoforms with bound peptides or serotonin N-acetyltransferase have been determined (20,21).…”

Oxidative Status of DJ-1-dependent Activation of Dopamine Synthesis through Interaction of Tyrosine Hydroxylase and 4-Dihydroxy-l-phenylalanine (l-DOPA) Decarboxylase with DJ-1

“…DJ-1 therefore stimulates TH activity both by up-regulation of TH gene expression and by protein-protein interaction, and DJ-1 stimulates DDC activity only by protein-protein interaction. Phosphorylation of Ser-19 of TH by various kinases stimulates TH activity (25)(26)(27)(28). Introduction of DJ-1 in vitro and in vivo, however, did not stimulate phosphorylation of TH, although its activity was increased ( Fig.…”