The binding of nonmuscle caldesmon from brain to microtubules Regulations by Ca2+‐calmodulin and cdc2 kinase

[摘要]

Nonmuscle caldesmon from bovine brain bound to microtubules with a stoichiometry of five tubulin dimers to one molecule of caldesmon with values of K _A 4.5×10⁵ M⁻¹. The binding of caldesmon to microtubules was inhibited in the presence of Ca²⁺ and calmodulin. The phosphorylation of caldesmon by cdc2 kinase also eliminated the microtubule-binding activity. These results suggest that caldesmon may play a physiological role in the functions of microtubules.

[学科分类] 生物化学/生物物理

[关键词] Caldesmon;Actin;Microtubule;Calmodulin;cdc2 kinase;PMSF;phenylmethylsulfonyl fluoride;EGTA;[ethylenebis(oxyethylenenitrilo)]tetraacetic acid;SDS-PAGE;sodium dodecyl sulfate-polyacrylamide gel electrophoresis;DTT;dithiothreitol;MES;2-(N-morpholino)ethanesulfonic acid