Modulation of type‐1 protein phosphatase by synthetic peptides corresponding to the carboxyl terminus

FEBS Letters

Brautigan, David L.¹  Martin, Bruce L.¹  Shriner, Carol L.¹ 

[1] Section of Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA

关键词: Phosphatase specificity;    Okadaic acid;    Peptide antibody;    Myosin light chain;    PP-1;    catalytic subunit of type-1 protein phosphatase;    PP-35K;    protease resistant catalytic fragment of PP-1;    MOPS;    3-(N-morpholino)-propanesulfonic acid;    DTT;    dithiothreitol;    PMSF;    phenylmethylsulfonyl fluoride;   

DOI  :  10.1016/0014-5793(91)80712-C

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protein phosphatase type-I (PP-1) has a protease resistant catalytic core M _r = 35000 (PP-35K) and a carboxyl terminal segment which affects activity with various substrates. We found that micromolar concentration of a synthetic peptide, corresponding to residues 312–326 of the PP-1 carboxyl terminus (P312-326) that is missing from PP-35K, increased the phosphatase activity of PP-35K with phosphorylase and myosin light chains as substrates by decreasing the apparent K _m without a change in V _m. Purified PP-1 and PP-35K were inhibited identically by okadaic acid, but peptide P312-326 only stimulated the activity of PP-35K, not full-length PP-1. Other peptides corresponding to the carboxyl terminus of phosphatase-2A or to the amino terminus of PP-1 did not affect the activity of PP-35K. A sequence conserved in PP-1 from different species, Pro-He-Thr-Pro-Pro was implicated as the active region because a derivative peptide, Ala-Pro-Ile-Thr-Pro-Pro-Ala, stimulated the activity of PP-35K to the same extent as peptide P312-326 although at higher concentrations. These results indicate that the carboxyl terminus of PP-1 interacts with the catalytic core to modulate its activity, and suggest that the physiological regulation of PP-1 may involve this segment.

【 授权许可】

Unknown