肌联蛋白:结构、亚型分类及功能调节

Titin: structure, isoforms and functional regulation

肌联蛋白(titin)作为生物体分子量最大的蛋白质,具有N2A、N2BA、N2B三种亚型,在肌肉基本结构维持、力的产生、传导与调节方面发挥重要作用。20世纪50年代以来肌肉收缩产力的解释建立在粗细肌丝滑行理论基础上,一定程度上忽略了骨架蛋白在力产生与传导中的贡献。随着肌纤维中不溶性蛋白残基与大分子量蛋白质的发现,除粗细肌丝外的第三肌丝——肌联蛋白逐渐进入人们视野。20世纪80年代后由于单分子力学技术与基因测序技术的发展,肌联蛋白在肌节中的详细排列、结构、弹性特性及组分的研究大量涌现。本文就肌联蛋白基本结构、亚型分类、弹性功能及调节因素进行综述,以期更好地了解肌联蛋白。

Titin, the largest known protein in the body expressed in three isoforms(N2A, N2BA and N2B), is essential for muscle structure, force generation, conduction and regulation. Since the 1950s, muscle contraction mechanisms have been explained by the sliding filament theory involving thin and thick muscle filaments, while the contribution of cytoskeleton in force generation and conduction was ignored. With the discovery of insoluble protein residues and large molecular weight proteins in muscle fibers, the third myofilament, titin, has been identified and attracted a lot of interests. The development of single molecule mechanics and gene sequencing technology further contributed to the extensive studies on the arrangement, structure, elastic properties and components of titin in sarcomere. Therefore, this paper reviews the structure, isforms classification, elastic function and regulatory factors of titin,to provide better understanding of titin.