Abstract：
Importin α has been described as a nuclear protein transport receptor that enables proteins synthesized in the cytoplasm to translocate into the nucleus. Besides its function in nuclear transport, an increasing number of studies have examined its non-nuclear transport functions. In both nuclear transport and non-nuclear transport, a functional domain called the IBB domain (importin β binding domain) plays a key role in regulating importin α behavior, and is a common interacting domain for multiple binding partners. However, it is not yet fully understood how the IBB domain interacts with multiple binding partners, which leads to the switching of importin α function. In this study, we have distinguished the location and propensities of amino acids important for each function of the importin α IBB domain by mapping the biochemical/physicochemical propensities of evolutionarily conserved amino acids of the IBB domain onto the structure associated with each function. We found important residues that are universally conserved for IBB functions across species and family members, in addition to those previously known, as well as residues that are presumed to be responsible for the differences in complex-forming ability among family members and for functional switching.
摘要：
输入蛋白α已被描述为核蛋白转运受体,其使得在细胞质中合成的蛋白质能够易位到细胞核中。除了它在核运输中的功能，越来越多的研究已经检查了它的非核运输功能。在核运输和非核运输中，一个名为IBB结构域（importinβ结合结构域）的功能结构域在调节importinα行为中起关键作用，并且是多个绑定伙伴的常见交互域。然而,尚未完全了解IBB域如何与多个结合伴侣相互作用，这导致了输入素α功能的转换。在这项研究中,我们通过将IBB结构域的进化保守氨基酸的生化/物理化学特征映射到与每种功能相关的结构上，区分了对importinαIBB结构域的每种功能重要的氨基酸的位置和特征。我们发现重要的残基对于跨物种和家族成员的IBB功能普遍保守，除了那些以前已知的，以及被认为是家族成员之间复合物形成能力差异和功能转换原因的残基。
