CALDESMON IS AN ELONGATED, FLEXIBLE MOLECULE LOCALIZED IN THE ACTOMYOSIN DOMAINS OF SMOOTH-MUSCLE
CALDESMON IS AN ELONGATED, FLEXIBLE MOLECULE LOCALIZED IN THE ACTOMYOSIN DOMAINS OF SMOOTH-MUSCLE
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DOI：
10.1002/j.1460-2075.1986.tb04206.x
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发表时间：
1986-02-01
期刊：
影响因子：
11.4
通讯作者：
SMALL, JV
中科院分区：
文献类型：
--
作者：
FURST, DO;CROSS, RA;SMALL, JV
已经开发出一种快速纯化方法，利用洗涤后的肌原纤维的 KI 提取物作为源材料，从猪胃平滑肌中分离钙结合蛋白。在 SDS-PAGE 上，该哺乳动物 caldesmon 显示出约 155 kd 的紧密排列的双峰。通过低角度旋转阴影，卡德斯蒙被证明是一种细长的、高度灵活的分子，它倾向于形成结构与细丝蛋白非常相似的端对端二聚体。当添加到 F-肌动蛋白溶液中时，卡尔德斯蒙显着增加了高剪切粘度，但增加的程度取决于样品制备。通过添加单特异性钙结合蛋白抗体后其完全可逆性，该效应被证明是由钙结合蛋白引起的，而不是由微量污染物引起的。最近的研究表明，在平滑肌中可以区分两个结构不同的结构域：肌动球蛋白结构域和肌动蛋白中间丝结构域。在光和电子显微镜水平上对平滑肌超薄切片进行的免疫细胞化学显示，钙结合蛋白存在于肌动球蛋白结构域中。因此，卡尔德斯蒙是平滑肌肌动球蛋白系统的潜在调节剂。
A rapid purification procedure has been developed for the isolation of caldesmon from hog stomach smooth muscle utilizing a KI extract of washed myofibrils as source material. On SDS-PAGE this mammalian caldesmon showed a closely-spaced doublet around 155 kd. By low-angle rotary shadowing caldesmon was shown to be an elongated, highly flexible molecule which tends to form end-to-end dimers that are structurally very similar to filamin. When added to F-actin solutions caldesmon increased the high-shear viscosity considerably, but by an extent that depended on sample preparation. The effect was shown to be due to caldesmon and not to a trace contaminant by its full reversibility after addition of a monospecific caldesmon antibody. Recent investigations have shown that in smooth muscle two structurally distinct domains can be distinguished: an actomyosin domain and an actin-intermediate filament domain. Immunocytochemistry of ultrathin sections of smooth muscle at the light and electon microscope level revealed that caldesmon is present in the actomyosin domain. Caldesmon is thus a potential regulator of the actomyosin system in smooth muscle.