螺旋-环-螺旋蛋白家族的分类和功能

Classification and Function of the Basic Helix-loop-helix Protein Class

含有螺旋-环-螺旋结构域的蛋白质是一类超家族蛋白,从细菌到哺乳动物中都广泛存在,且有较高的保守性。根据螺旋-环-螺旋蛋白的DNA结合能力、一些保守区的出现与否以及与E-box等顺式因子的结合特性等,可以把这个家族分成六类。螺旋-环-螺旋蛋白主要通过自身形成二聚体或与其他蛋白质形成异源二聚体而发挥其生物学功能。大部分已知的螺旋-环-螺旋蛋白是转录因子,它们常常通过抑制或活化与生长、分化有关的基因来改变细胞的进程。在动物中对这个家族的研究已经有比较长的历史,研究表明这个家族的基因与细胞的生长、衰老、肿瘤的发生以及神经发育、果蝇的性别决定等有关;近期在植物中的研究也表明它们有广泛的功能,如参与植物抗冻、抗干旱等的应答反应,以及在根、花药等器官的发育过程中起重要作用等。本文就螺旋-环-螺旋转录因子家族的分类和功能研究进展作简要介绍。

The basic helix-loop-helix-like protein belongs to a protein superfamily, and the most obvious character of this superfamily is the highly conserved helix-loop-helix domain, which exists in organisms from bacteria to mammals. Based on the DNA-binding activity, existence of conserved motifs outside the helix-loop-helix domain and binding speciality of the E-box, helix-loop-helix superfamily was classified into six subfamilies. Proteins in this superfamily function through formation of homodimer or heterodimer between different family members. Most of the proteins in this superfamily are transcription factors, and usually function to change cellular course by depressing or activation genes that is related to growth or differentiation. It has been demonstrated that this kind of proteins is involved in cell growth, cell senescence, cancer develop, nerves development and drosophila sex decision. Recent studies indicated that helix-loop-helix proteins also play important roles in plant, mediating signal transduction in processes such as freezing tolerance, drought tolerance and root development, anther development, etc.. In this paper, we give a brief review of the classification and functions of this protein superfamily.