Kellermayer M S, Granzier H L
Department of Veterinary Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, 99164-6520, USA.
FEBS Lett. 1996 Feb 19;380(3):281-6. doi: 10.1016/0014-5793(96)00055-5.
Titin ( also known as connectin) is a giant filamentous protein that spans the distance between the Z- and M-lines of the vertebrate muscle sarcomere and plays a fundamental role in the generation of passive tension. Titin has been shown to bind strongly to myosin, making it tightly associated to the thick filament in the sarcomere. Recent observations have suggested the possibility that titin also interacts with actin, implying further functions of titin in muscle contraction. We show -- using in vitro motility and binding assays -- that native titin interacts with both filamentous actin and reconstituted thin filaments. The interaction results in the inhibition of the filaments' in vitro motility. Furthermore, the titin-thin filament interaction occurs in a calcium-dependent manner: increased calcium results in enhanced binding of thin filaments to titin and greater suppression of in vitro motility.
肌联蛋白（也称为连接蛋白）是一种巨大的丝状蛋白，它跨越脊椎动物肌节的Z线和M线之间的距离，并在被动张力的产生中起基本作用。已表明肌联蛋白与肌球蛋白强烈结合，使其与肌节中的粗肌丝紧密相连。最近的观察结果表明，肌联蛋白也可能与肌动蛋白相互作用，这意味着肌联蛋白在肌肉收缩中还有其他功能。我们通过体外运动性和结合试验表明，天然肌联蛋白与丝状肌动蛋白和重组细肌丝都相互作用。这种相互作用导致细肌丝体外运动性受到抑制。此外，肌联蛋白与细肌丝的相互作用以钙依赖的方式发生：钙浓度增加会导致细肌丝与肌联蛋白的结合增强，体外运动性受到更大抑制。
