Evidence against the regulation of caldesmon inhibitory activity by p42/p44erk mitogen‐activated protein kinase in vitro and demonstration of another caldesmon kinase in intact gizzard smooth muscle

FEBS Letters

Krymsky, Mikhail A.²  Vorotnikov, Alexander V.²  Shirinsky, Vladimir P.²  Chibalina, Margarita V.²  Marston, Steven B.¹ 

[1] Cardiac Medicine, National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW3 6LY, UK;Laboratory of Cell Motility, Institute of Experimental Cardiology, Cardiology Research Center, Cherepkovskaya 15, Moscow 121552, Russia

关键词: Caldesmon;    Phosphorylation;    Mitogen-activated protein kinase;    Chicken gizzard;    CaMKII;    Ca2+/calmodulin-dependent protein kinase II;    CK2;    casein kinase II;    GST;    glutathione S-transferase;    HMM;    heavy meromyosin;    MAP kinase;    p42/p44erk mitogen-activated protein kinase;    PDBu;    phorbol 12;    13-dibutyrate;    PKC;    protein kinase C;   

DOI  :  10.1016/S0014-5793(99)00641-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effect of direct phosphorylation by recombinant p44^erk1 mitogen-activated protein kinase on the inhibitory activity of caldesmon and its C-terminal fragment H1 was studied in vitro. Neither inhibition of actin-tropomyosin activated ATPase of heavy meromyosin by caldesmon or H1, nor inhibition of the actin-tropomyosin motility over heavy meromyosin by H1 was significantly affected by the phosphorylation while only a moderate effect on the actin-activated component of heavy meromyosin ATPase inhibition was observed. Phosphopeptide mapping of caldesmon immunoprecipitated from [³²P]PO₄-labelled intact gizzard strips revealed that it is predominantly phosphorylated at mitogen-activated protein kinase sites in unstimulated tissue and that it is stimulated for 1 h with phorbol 12,13-dibutyrate. We find that phorbol 12,13-dibutyrate also induces a transitory phosphorylation of caldesmon peaking at 15 min after addition and this phosphorylation is not attributed to mitogen-activated protein kinase, protein kinase C, Ca²⁺/calmodulin-dependent kinase II or casein kinase II. We suggest that a yet unidentified kinase, rather than mitogen-activated protein kinase, may be involved in regulation of the caldesmon function in vivo.

【 授权许可】

Unknown