INPP4B
小结
INPP4B是抑癌基因，编码蛋白是一种脂质肌醇多磷酸4-磷酸酶，具有负调节PI3K/Akt信号通路的作用。INPP4B的主要功能是选择性地水解肌醇环上的4位磷酸基团，将Pi（3,4）P2转化成PI（3）P。INPP4B通过控制PI3K/Akt途径，INPP4B抑制小鼠体内细胞增殖、细胞运动和肿瘤生长。在乳腺癌和卵巢癌患者中已经鉴定出了INPP4B杂合性缺失，提示INPP4B作为抑癌基因发挥作用。乳腺癌细胞系和小鼠模型中的功能缺失研究表明，INPP4B表达水平降低会导致AKT表达增强、细胞侵袭和肿瘤进展。在乳腺癌、卵巢癌和前列腺癌中观察到了INPP4B表达的缺失，并与总体生存率降低有关。
INPP4B is a lipid inositol polyphosphate 4-phosphatase that has a role in negatively regulating the PI3K/AKT signaling pathway. The primary function of INPP4B is to selectively hydrolyze the position 4 phosphate group on the inositol ring, converting PI(3, 4)P2 to PI(3)P. INPP4B has been implicated in the suppression of cell proliferation, cell motility and tumor growth in mice via control of the PI3K/AKT pathway. INPP4B loss of heterozygosity has been identified in breast and ovarian cancer patients, suggesting that INPP4B functions as a tumor suppressor. Loss-of-function studies in breast cancer cell line and murine models demonstrate that reduced expression of INPP4B results in enhanced AKT expression, cell invasiveness, and tumor progression. Loss of INPP4B expression is observed in breast, ovarian, and prostate cancers, and correlates with lower overall survival.