Identification of protein phosphatase 2A as the major tyrosine hydroxylase phosphatase in adrenal medulla and corpus striatum: evidence from the effects of okadaic acid

FEBS Letters

Flatmark, Torgeir¹  Haavik, Jan¹  Andersson, Kristoffer K.¹  Campbell, David G.²  Cohen, Philip²  Schelling, Donald L.² 

[1] Department of Biochemistry, University of Bergen, Bergen, Norway UK;Department of Biochemistry, University of Dundee, Dundee, Scotland

关键词: Tyrosine hydroxylase;    Protein phosphatase;    cyclic AMP;    Calmodulin;    Protein kinase;    Okadaic acid;    Protein sequencing;    TH;    tyrosine hydroxylase;    A-kinase;    cyclic AMP-dependent protein kinase;    CaM-MPK;    calmodulin-dependent multiprotein kinase;   

DOI  :  10.1016/0014-5793(89)81424-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

(i) The major sites on bovine adrenal tyrosine hydroxylase (TH) phosphorylated by calmodulin-dependent multiprotein kinase (CaM-MPK) and cyclic AMP-dependent protein kinase were shown to be Ser-19 and Ser-40, respectively, while Ser-40 was also phosphorylated slowly by CAM-MPK. (ii) Type 2A and type 2C phosphatases accounted for ≈90% and ≈ 10% of TH phosphatase activity, respectively, in extracts of adrenal medulla and corpus striatum assayed at near physiological free Mg²⁺(1 mM), while type 1 and type 2B phosphatases had negligible activity towards TH. (iii) Incubation of adrenal chromaffin cells with okadaic acid increased TH phosphorylation by 206% and activity by 77%, establishing that type 2A phosphatases play a major role in regulating TH in vivo.

【 授权许可】

Unknown