Phosphorylation sequences in h‐caldesmon from phorbol ester‐stimulated canine aortas

FEBS Letters

Hathaway, David R.¹  Gapinski, Connie J.¹  Adam, Leonard P.¹ 

[1] Department of Medicine and The Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA

关键词: Caldesmon;    Smooth muscle;    Protein phosphorylation;    Protein kinase C;    Proline-directed protein kinase;    EGTA;    [ethylenebis(oxyethylenenitrilo)]tetraacetic acid;    EDTA;    ethylenediaminetetraacetic acid;    MOPS;    morpholinopropane sulfonic acid;    PKC;    protein kinase C;    PDBu;    phorbol-12;    13-dibutyrate;    TPCK;    N-tosyl-l-phenylalanine chloromethyl ketone;    TLCK;    Nα-p-tosyl-l-lysine chloromethyl ketone;    PMSF;    phenylmethylsulfonyl fluoride;   

DOI  :  10.1016/0014-5793(92)80446-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The high molecular weight form of caldesmon (h-caldesmon) is phosphorylated in vascular smooth muscle. The stoichiometry of caldesmon phosphorylation increases in response to stimulation of the muscle by several contractile agonists; however, the responsible kinase has not been identified. In this study, we have sequenced the phosphopeptides prepared from h-caldesmon phosphorylated in vitro by protein kinase C (PKC) as well as the phosphopeptides prepared from caldesmon phosphorylated in intact canine aortas that were stimulated to contract with PDBu. PKC phosphorylated three sites located in the C terminus: GSS*LKIEE, AEFLNKS*VQK and NLWEKQS*VDK, while h-caldesmon from intact tissue was phosphorylated at two separate sites also in the C terminus: VTS*PTKV and S*PAPK. By comparison to known substrate consensus sequences for various protein kinases these data suggest that h-caldesmon is directly phosphorylated by a proline-directed protein kinase and not by PKC.

【 授权许可】

Unknown