Hsp70 chaperones interact with substrate proteins in a coordinated fashion that is regulated by nucleotides and enhanced by assisting cochaperones. There are numerous homologues and isoforms of Hsp70 that participate in a wide variety of cellular functions. This diversity can facilitate adaption or specialization based on particular biological activity and location within the cell. In this review, we highlight two specialized binding partner proteins, Tim44 and IRE1, that interact with Hsp70 at the membrane in order to serve their respective roles in protein translocation and unfolded protein response signalling. Recent mechanistic data suggest analogy in the way the two Hsp70 homologues (BiP and mtHsp70) can bind and release from IRE1 and Tim44 upon substrate engagement. These shared mechanistic features may underlie how Hsp70 interacts with specialized binding partners and may extend our understanding of the mechanistic repertoire that Hsp70 chaperones possess.

Hsp70 伴侣以协调的方式与底物蛋白相互作用，该方式由核苷酸调节并通过辅助共伴侣增强。 Hsp70 有许多同源物和亚型，参与多种细胞功能。这种多样性可以促进基于特定生物活性和细胞内位置的适应或专门化。在这篇综述中，我们重点介绍了两种专门的结合伴侣蛋白 Tim44 和 IRE1，它们在膜上与 Hsp70 相互作用，以在蛋白质易位和未折叠蛋白质反应信号传导中发挥各自的作用。最近的机械数据表明，两种 Hsp70 同源物（BiP 和 mtHsp70）在底物接合时与 IRE1 和 Tim44 结合和释放的方式类似。这些共同的机制特征可能是 Hsp70 如何与专门的结合伙伴相互作用的基础，并可能扩展我们对 Hsp70 伴侣所拥有的机制库的理解。