PIK3R3（phosphoinositide-3-kinase regulatory subunit 3），癌症关联基因，基因ID：8503，磷脂酰肌醇3激酶（pi3k）磷酸化磷脂酰肌醇和类似的化合物，然后作为第二信使的生长信号途径。pi3k由一个催化亚基和一个调节亚基组成。该基因编码的蛋白代表pi3k的一个调节亚单位，编码的蛋白包含两个sh2结构域，通过这两个结构域结合活化的蛋白酪氨酸激酶来调节其活性。[由RefSeq提供，2016年6月]Phosphatidylinositol 3-kinase (PI3K) phosphorylates phosphatidylinositol and similar compounds， which then serve as second messengers in growth signaling pathways. PI3K is composed of a catalytic and a regulatory subunit. The protein encoded by this gene represents a regulatory subunit of PI3K. The encoded protein contains two SH2 domains through which it binds activated protein tyrosine kinases to regulate their activity. [provided by RefSeq， Jun 2016]。