细胞初级纤毛是细胞膜表面感应外界信号的重要感应细胞器。许多外界信号，如生长因子（growth factors）、形态发生素（morphogens）和机械张力都是通过位于细胞膜纤毛中的受体或纤毛本身的弯曲作用于细胞，从而激活细胞内的信号通络。纤毛在感应信号时，一方面接受外界配体的作用，另一方面募集细胞内的信号分子，通过纤毛的组织，促进信号分子的相互作用。热休克蛋白质Hsp90a是纤毛基部参与信号募集以及稳定的重要分子伴侣蛋白质，它在纤毛基部形成的信号分子-分子伴侣复合体起到了稳定信号分子蛋白质以及促进它们相互作用的功能。研究发现Hsp90a普遍存在于所有的纤毛中，比如纤毛特化形成的视杆细胞以及精子尾巴。作为一个重要的分子伴侣蛋白质，Hsp90是许多抗肿瘤药物的靶蛋白，有近20种Hsp90的抑制剂作为抗肿瘤药物在临床实验中。初步研究表明，Hsp90抑制剂对于纤毛的功能具有显著的抑制作用。

Primary cilia are cellular membrane protrusions that can sense and mediate the extracellular stimuli and are considered as sensory organelle. Many extracellular signals, such as growth factors, morphogens and even mechanic force, are sensed by cilia through the membrane receptors or cilia bending. And the signals are passed into the intracellular molecules through intraflagellar transportation. Many intracellular signal molecules are recruited to cilia or the ciliary basal body. Thus, primary cilia organize the membrane receptor and its downstream signal molecules into a signaling apparatus. The organization of primary cilia facilitates the interactions between the receptor and signal molecules. .Heat shock protein Hsp90alfa is a molecular chaperone and is identified to be an important chaperone at the base of cilia. It helps to recruit intracellular signal molecules into ciliary base and stabilizes those recruited signal molecules. At ciliary base, Hsp90alfa and the recruited signal molecules form a chaperone-signal molecule complex. Within this complex, Hsp90alfa provides a chaperone platform to stabilize the signal molecules and to facilitate their interactions. Thus, Hsp90alfa plays as an important mediator in cilia mediated membrane receptor signal transduction. For example, during cilia mediated IGF-1 receptor signaling Hsp90alfa helps to recruit IRS-1, the direct downstream substrate of IGF-1 receptor kinase, into the basal body from which IRS-1 is transported alone the ciliary axoneme, phosphorylated by the receptor kinase in axonemal membrane and transported back to the Hsp90alfa platform at the base to interact with other signal molecules. .Hsp90alfa has been identified in all the cilia examined, including the specialized cilia formed rod cells in retina, the sperm flagellum and the motile cilia of tracheal epithelial cells. On the other hand, Hsp90 has been gaining the momentum to be an important molecular target for the development of anti-cancer drugs in the past 20 years. About 20 different inhibitors of Hsp90 chaperone activity have been under clinical trial for their cancer therapeutic efficacy. It is essential to evaluate the effect of Hsp90 inhibitor on its cilia-related functions. As cilia are ubiquitously present in most type of cells, the understanding of the function of Hsp90 in cilia will help to develop anti-cancer Hsp90 inhibitor that focus on cancer cells rather than affect many ciliary cells.