PREX2

该基因编码的蛋白属于磷脂酰肌醇3，4，5-三磷酸（PIP3）依赖性rac交换子（prex）家族，是rac家族小G蛋白的DBL型鸟嘌呤核苷酸交换因子。该蛋白的结构域包括催化弥漫性B细胞淋巴瘤同源性和普雷克星同源性（DHPH）域、两个不齐的EGL-10和普雷克星同源性（DEP）域、两个PDZ域和一个在其中一个亚型中发现的C端肌醇多磷酸-4磷酸酶（IP4P）域。这种蛋白促进了在rac1上的gdp与gtp的交换，允许gtp结合的rac1激活下游效应器。研究还表明，该蛋白的Pleckstrin同源域与磷酸酶和紧张素同源（PTEN）基因产物相互作用，抑制PTEN磷酸酶活性，从而激活磷酸肌醇-3激酶（PI3K）信号通路。相反，PTEN基因产物也被证明能抑制这种蛋白的GEF活性。该基因在胰岛素信号传导途径中起作用，在一些癌症中观察到该基因的突变或过度表达。
The protein encoded by this gene belongs to the phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger (PREX) family, which are Dbl-type guanine-nucleotide exchange factors for Rac family small G proteins. Structural domains of this protein include the catalytic diffuse B-cell lymphoma homology and pleckstrin homology (DHPH) domain, two disheveled, EGL-10, and pleckstrin homology (DEP) domains, two PDZ domains, and a C-terminal inositol polyphosphate-4 phosphatase (IP4P) domain that is found in one of the isoforms. This protein facilitates the exchange of GDP for GTP on Rac1, allowing the GTP-bound Rac1 to activate downstream effectors. Studies also show that the pleckstrin homology domain of this protein interacts with the phosphatase and tensin homolog (PTEN) gene product to inhibit PTEN phosphatase activity, thus activating the phosphoinositide-3 kinase (PI3K) signaling pathway. Conversely, the PTEN gene product has also been shown to inhibit the GEF activity of this protein. This gene plays a role in insulin-signaling pathways, and either mutations or overexpression of this gene have been observed in some cancers.