Prothymosin α is phosphorylated by casein kinase‐2

FEBS Letters

Barcia, Miguel G.¹  Jullien, Cristina D.¹  Freire, Manuel¹  Castro, José M.¹  González, Carlos G.¹ 

[1] Departamento de Bioquímica e Bioloxía Molecular, Facultade de Bioloxía, Universidade de Santiago de Compostela, Galicia, Spain

关键词: Prothymosin α;    Thymosin α1;    Casein kinase-2;    EGTA;    [ethylenebis(oxyethylenenitrilo)]tetraacetic acid;    CK-2;    casein kinase-2;    ProTα;    prothymosin α;    Tα1;    thymosin α1;    HPLC;    high performance liquid chromatography;   

DOI  :  10.1016/0014-5793(92)80924-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Prothymosin α (ProTα) is a 12.5 kDa acidic polypeptide that is considered to have a nuclear function related to cell proliferation. Inspection of its amino acid sequence revealed the presence of sequences that may serve as targets for phosphorylation by casein kinase-2 (CK-2). ProTα isolated from calf thymocytes was phosphorylated in vitro by CK-2. The phosphorylation sites are Ser and Thr residues located among the first 14 amino acid residues in the ProTα sequence. Another site that is theoretically suitable for phosphorylation by CK-2, at the C-terminus of the polypeptide, is not, in fact, phosphorylated. Thymosin α₁ (Tα₁), a peptide whose sequence corresponds to the first 28 amino acids of ProTα, is also phosphorylated by CK-2 at the same phosphorylation sites as ProTα. In cultured splenic lymphocytes ProTα was phosphorylated at Thr residues located at positions 7, 12 and/or 13. Based on these observations we conclude that CK-2, or another cellular kinase with similar sequence specifity, is responsible for phosphorylation of ProTα in vivo.

【 授权许可】

Unknown