Lara-Lemus Roberto
Department of Research in Biochemistry, Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas". Mexico City, 14080. Mexico.
J Cancer. 2019 May 21;10(10):2312-2318. doi: 10.7150/jca.30376. eCollection 2019.
Myelin and lymphocyte protein (MAL) is an integral membrane protein constituent of lipid rafts, and it is implicated in apical transport of proteins in polarized epithelial cells. However, beyond the involvement of MAL in apical sorting and as its function as a raft stabilizer, it is still not totally clear how MAL participates in cell proliferating processes. More controversial and interesting is the fact that MAL has been implicated in carcinogenesis in two opposite ways. First, this protein is overexpressed in ovarian cancer and some kinds of lymphomas where it seems to favor cancer progression. Conversely, it has been reported that downregulation of the gene by promoter hypermethylation is a hallmark of several adenocarcinomas. So far, there is not enough experimental evidence to help us understand this phenomenon, and no mutations or MAL isoforms have been associated with these opposite functions. This review provides an updated summary of the structure and functions of MAL, and we will discuss the possible mechanisms underlying its roles as a tumor suppressor and a tumor progression factor.
髓鞘与淋巴细胞蛋白（MAL）是脂筏的一种整合膜蛋白成分，它与极化上皮细胞中蛋白质的顶端运输有关。然而，除了MAL参与顶端分选及其作为脂筏稳定剂的功能外，MAL如何参与细胞增殖过程仍不完全清楚。更具争议性且有趣的是，MAL在致癌过程中以两种相反的方式发挥作用。首先，这种蛋白在卵巢癌和某些类型的淋巴瘤中过度表达，似乎有利于癌症进展。相反，据报道，该基因通过启动子高甲基化而下调是几种腺癌的一个标志。到目前为止，没有足够的实验证据帮助我们理解这一现象，并且没有发现与这些相反功能相关的MAL突变或异构体。本综述提供了MAL结构和功能的最新总结，我们将讨论其作为肿瘤抑制因子和肿瘤进展因子的潜在作用机制。
