应激诱导的磷蛋白1（STIP1，也称为HSP70-HSP90组织蛋白质或啤酒花）用作热休克蛋白（HSP）70和HSP90之间作为蜂窝装配机器的​​一部分之间的相互作用的介质。它还调节HSP70和HSP90两者的ATP酶活性，从而促进两者之间的客户蛋白转移。STIP1是由三种脂肽重复域（TPR1，TPR2A，TPR2B）组成的单体蛋白，参与蛋白质 - 蛋白质相互作用，以及涉及客户端激活的两个小天冬氨酸 - 脯氨酸重复域（Scheufler C等人。2000; Nelson Gm等人。2003; yif等，2010;施密亚州等。2012）。STIP1（HOP）的灵活连接器将TPR1-DP1和TPR2A-TPR2B-DP2模块连接为TPR1-DP1-TPR2A-TPR2B-DP2（Scheufler C等人。2000）。生化和结晶分析显示，STIP1的TPR结构域与HSP70或HSP90伴侣的C末端MEEVD基序相互作用;TPR2A优先结合至HSP90，而TPR1和TPR2B与HSP70结合（Scheufler C等人2000; Carrigan Pe等，2006; Schmid Ab等，2012）。此外，低温电子显微镜（Cryo-EM）的人HSP90：STIP1复合物揭示了STIP1还可以在Hsp90的若干其他部分，预组织Hsp90的N-末端结构域（NTDS）中形成相互作用，从而增加核苷酸的可达性- 缠绕口袋（Southworth Dr＆Agard DA 2011）。STIP1稳定一个替代的HSP90开放状态，HSP90单体的疏水客户端绑定表面已经融合了客户端载荷（Southworth Dr＆Agard DA 2011）的剩余可接受的。STIP1定位有来自HSP90二聚体裂隙延伸的TPR1结构域，其可用于与HSP70的相互作用。在STIP1稳定的HSP90构象中，N末端域已经旋转以匹配闭合的ATP构象。 However, the arrangement of the STIP1 domains in the complex seems to prevent the NTDs dimerization of HSP90 monomers and total closure of the HSP90 dimer that is required for an efficient HSP90-mediated ATP hydrolysis (Southworth DR & Agard DA 2011; Alvira S et al. 2014). HSP70, in the ADP state, readily binds HSP90:STIP1, forming a client-loading complex HSP90:STIP1:HSP70:client protein (Hernández MP et al. 2002). Structural studies of GR-LBD (the ligand-binding domain of the glucocorticoid receptor) bound to HSP90:STIP1:HSP70 complex showed that one STIP1 molecule binds to the HSP90 dimer and through domain rearrangement, gives rise to two main conformations, an extended structure that recognizes and interacts with HSP70, and a compact one in which HSP70 is in contact with one HSP90 monomer (Alvira S et al. 2014). Movement between these two modes is thought to deliver the HSP70-bound substrate to the side of the HSP90 dimer opposite the site of STIP1 binding (Alvira S et al. 2014). Following client delivery by HSP70 and STIP1 release, HSP90:ATP converts to the closed ATP hydrolysis-active state to complete the chaperone cycling.