D'Souza Ryan S, Casanova James E
a Department of Cell Biology , University of Virginia Health System , Charlottesville , VA , USA.
Small GTPases. 2016 Oct;7(4):257-264. doi: 10.1080/21541248.2016.1219442. Epub 2016 Oct 14.
The IQSec/BRAG proteins are a subfamily of Arf-nucleotide exchange factors. Since their discovery almost 15 y ago, the BRAGs have been reported to be involved in diverse physiological processes from myoblast fusion, neuronal pathfinding and angiogenesis, to pathophysiological processes including X-linked intellectual disability and tumor metastasis. In this review we will address how, in each of these situations, the BRAGs are thought to regulate the surface levels of adhesive and signaling receptors. While in most cases BRAGs are thought to enhance the endocytosis of these receptors, how they achieve this remains unclear. Similarly, while all 3 BRAG proteins contain calmodulin-binding IQ motifs, little is known about how their activities might be regulated by calcium. These are some of the questions that are likely to form the basis of future research.
IQSec/BRAG蛋白是Arf核苷酸交换因子的一个亚家族。自近15年前被发现以来，已有报道称BRAG蛋白参与了从成肌细胞融合、神经元路径寻找和血管生成到病理生理过程（包括X连锁智力障碍和肿瘤转移）等多种生理过程。在本综述中，我们将探讨在上述每种情况下，BRAG蛋白被认为是如何调节黏附受体和信号受体的表面水平的。虽然在大多数情况下，BRAG蛋白被认为可增强这些受体的内吞作用，但其具体实现方式仍不清楚。同样，虽然所有3种BRAG蛋白都含有与钙调蛋白结合的IQ基序，但对于钙如何调节它们的活性却知之甚少。这些问题可能构成未来研究的基础。
