Pritchard K, Moody C J
Cell Calcium. 1986 Dec;7(5-6):309-27. doi: 10.1016/0143-4160(86)90035-7.
The protein caldesmon, originally isolated from smooth muscle tissue where it is the most abundant calmodulin-binding protein, has since been shown to have a wide distribution in actin- and myosin- containing cells where it is localized in sub-cellular structures concerned with motility, shape changes and exo- or endo-cytosis. Caldesmon is believed to be an actin- regulatory protein, and binds with high affinity to actin or actin-tropomyosin. Caldesmon inhibits the activation by actin-tropomyosin of myosin MgATPase activity, and the inhibition can be reversed by Ca2+.calmodulin. The binding of caldesmon to smooth muscle proteins has been studied in detail, enabling a model to be constructed which could account for the observed Ca2+ regulation of smooth muscle thin filaments. The abundance of caldesmon, and the Ca2+-regulation of its activity via calmodulin, mean that it is potentially an important intracellular regulator of processes such as smooth muscle contraction, cell motility and secretion.
钙调蛋白最初是从平滑肌组织中分离出来的，在平滑肌组织中它是最丰富的钙调蛋白结合蛋白，此后已证明它在含有肌动蛋白和肌球蛋白的细胞中广泛分布，定位于与运动、形状变化及胞吐或胞吞作用有关的亚细胞结构中。钙调蛋白被认为是一种肌动蛋白调节蛋白，能与肌动蛋白或肌动蛋白-原肌球蛋白高亲和力结合。钙调蛋白抑制肌动蛋白-原肌球蛋白对肌球蛋白MgATP酶活性的激活作用，且这种抑制作用可被Ca2⁺-钙调蛋白逆转。对钙调蛋白与平滑肌蛋白的结合已进行了详细研究，从而构建出一个模型，该模型可以解释所观察到的平滑肌细肌丝的Ca2⁺调节机制。钙调蛋白的丰富含量及其通过钙调蛋白对其活性的Ca2⁺调节作用，意味着它可能是平滑肌收缩、细胞运动和分泌等过程的重要细胞内调节因子。
