PREX2
小结
PREX2编码蛋白是一种RAC1 GTP酶的阳性介质，其促进在RAC1上GDP与GTP发生交换，从而引起其下游效应物的激活。PREX2由磷脂酰肌醇3，4，5-三磷酸（PIP3）和G蛋白偶联受体激活，并介导PI3K通路依赖性的RAC1激活。PREX2通过拮抗PTEN抑制作用而激活PI3激酶（PI3K）通路；相反，PTEN负调控了PREX2介导的致癌作用。在NRAS突变的黑色素瘤中，PREX2激活增加细胞增殖，激活PI3K信号转导，下调CDKN1C等肿瘤抑制因子。PREX2在黑素瘤和其他皮肤癌以及胰腺肿瘤中发生突变。
The PREX2 gene encodes a protein that facilitates the exchange of GDP to GTP on RAC1, leading to the activation of its downstream effectors. PREX2 is activated by phosphatidylinositol 3, 4, 5-trisphosphate (PIP3) and G-protein coupled receptors and mediates the PI3K pathway-dependent activation of RAC1. PREX2 can activate the PI3-Kinase (PI3K) pathway by antagonizing PTEN inhibitory effects; conversely, PTEN negatively regulates PREX2-mediated oncogenic effects. PREX2 activation increases cell proliferation, activates PI3K signaling and downregulates tumor suppressors such as CDKN1C in NRAS-mutant melanoma. Oncogenic effects of PREX2 have also been described in other cancers, as well as a role for PREX2 in the insulin signaling pathway. PREX2 is mutated in melanomas and other skin cancers, as well as in pancreatic tumors.