干细胞(stem cell,SC)是一类具有自我复制能力(self-renewal)的多潜能细胞,在干细胞微环境中能不断地进行自我更新,即通过自身增殖分裂和抑制分化来增加细胞的数目,且保持细胞的多能性。Hippo通路下游效应分子YAP为一癌基因,可与转录因子TEAD结合,形成一种强效的转录共激活因子。在生理条件下,通过激酶级联反应,YAP被磷酸化,其转录活性被抑制,从而限制器官的过度生长和抑制肿瘤的发生。研究已经证实,YAP的活化可以促进细胞的增殖并抑制细胞的分化,是一个高效的增长诱导剂。YAP在多能干细胞、神经干细胞、造血干细胞及表皮干细胞等的增殖和分化中起重要的作用,并可能调节卵巢生殖干细胞的增殖和分化。
Stem cell is a kind of self-renewable pluripotent cell. It can constantly self-renewal in stem cell niche, which through its own proliferation division and inhibition of differentiation to increase the number, and remain the pluripotent. YAP, as a oncogene, is the downstream effector of the Hippo pathway. It is a potent transcription coactivator acting via binding to the TEAD transcription factor. YAP is phosphorylated and inhibited by the upstream kinase cascade actions, then the inactivated YAP limits organ overgrowth and inhibits tumorigenesis. Studies have demonstrated that YAP is an efficient growth-inducing agent, which can promote cell proliferation and inhibit differentiation. YAP plays an important role in pluripotent stem cell, neural stem cell, hematopoietic stem cell and epidermal stem cell proliferation and differentiation, and may also regulate the ovarian germline stem cell proliferation and differentiation.