Complexes between 15 kDa caldesmon fragment and actin investigated by immuno‐electron microscopy

FEBS Letters

Mornet, Dominique²  Audemard, Etienne¹  Cavadore, Claude¹  Harricane, Marie-Cécile¹ 

[1] Centre de Biochimie Macromoléculaire du CNRS, INSERM U. 249, Université de Montpellier 1, 34033 Montpellier cédex 1, France;INSERM U.300, Faculté de Pharmacie, Bât K., Avenue Ch. Flahault, 34060 Montpellier cédex 1, France

关键词: Immune-electron microscopy;    Actin;    Caldesmon;   

DOI  :  10.1016/0014-5793(90)81150-M

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The regulatory system of smooth muscle thin filaments is thought to involve a major calcium-calmodulin and actin binding protein: caldesmon. A dissective approach was used to isolate a 35 kDa C-terminal fragment of the molecule and to produce antibodies reacting against both the intact and the 15 kDa N-terminal end of this parental fragment. While this purified 15 kDa caldesmon fragment demonstrates a weak actin association, we observed that it cross-links actin filaments into loose bundles. These structures were labelled with a selective antibody and showed regular periodic striation with repeats of approximately 40 nm. This work brings additional information to previous reports using an actin and calmodulin binding 25 kDa C-terminal fragment of the caldesmon molecule [(1989) J. Biol. Chem. 264, 2869-2875]. We demonstrate that a purified fragment corresponding to a sequence smaller than 96 amino acids, which contains no cystein residue, is able to interact with actin at a single site which is not the calmodulin modulated.

【 授权许可】

Unknown