Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Instituto Federal de Ciência e Tecnologia de São Paulo, Jacareí, SP, Brazil.
Sci Rep. 2018 Oct 24;8(1):15690. doi: 10.1038/s41598-018-33955-1.
GRASPs are proteins involved in cell processes that seem paradoxical: responsible for shaping the Golgi cisternae and involved in unconventional secretion mechanisms that bypass the Golgi. Despite its physiological relevance, there is still a considerable lack of studies on full-length GRASPs. Our group has previously reported an unexpected behavior of the full-length GRASP from the fungus C. neoformans: its intrinsically-disordered characteristic. Here, we generalize this finding by showing that it is also observed in the GRASP from S. cerevisae (Grh1), which strongly suggests it might be a general property within the GRASP family. Furthermore, Grh1 is also able to form amyloid-like fibrils either upon heating or when submitted to changes in the dielectric constant of its surroundings, a condition that is experienced by the protein when in close contact with membranes of cell compartments, such as the Golgi apparatus. Intrinsic disorder and fibril formation can thus be two structural properties exploited by GRASP during its functional cycle.
GRASPs 是参与细胞过程的蛋白质，这些过程似乎自相矛盾：它们负责塑造高尔基体潴泡，并参与绕过高尔基体的非常规分泌机制。尽管它具有生理相关性，但关于全长 GRASPs 的研究仍然相当缺乏。我们的小组之前曾报道过真菌 C. neoformans 全长 GRASP 的一种意外行为：其固有无序的特征。在这里，我们通过显示它也存在于酿酒酵母（Grh1）的 GRASP 中，从而推广了这一发现，这强烈表明它可能是 GRASP 家族中的一个普遍特性。此外，Grh1 还能够在加热或周围介电常数发生变化时形成类似淀粉样的纤维，当与细胞区室的膜（如高尔基体）紧密接触时，蛋白质会经历这种情况。因此，固有无序和纤维形成可以是 GRASP 在其功能循环中利用的两种结构特性。
