Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany.
Mol Microbiol. 2022 Apr;117(4):790-801. doi: 10.1111/mmi.14872. Epub 2022 Jan 8.
Many prokaryotes show complex behaviors that require the intricate spatial and temporal organization of cellular protein machineries, leading to asymmetrical protein distribution and cell polarity. One such behavior is cyanobacterial phototaxis which relies on the dynamic localization of the Type IV pilus motor proteins in response to light. In the cyanobacterium Synechocystis, various signaling systems encompassing chemotaxis-related CheY- and PatA-like response regulators are critical players in switching between positive and negative phototaxis depending on the light intensity and wavelength. In this study, we show that PatA-type regulators evolved from chemosensory systems. Using fluorescence microscopy and yeast two-hybrid analysis, we demonstrate that they localize to the inner membrane, where they interact with the N-terminal cytoplasmic domain of PilC and the pilus assembly ATPase PilB1. By separately expressing the subdomains of the response regulator PixE, we confirm that only the N-terminal PATAN domain interacts with PilB1, localizes to the membrane, and is sufficient to reverse phototactic orientation. These experiments established that the PATAN domain is the principal output domain of PatA-type regulators which we presume to modulate pilus extension by binding to the pilus motor components.
许多原核生物表现出复杂的行为，这些行为需要细胞蛋白机器的精细时空组织，从而导致蛋白质的不对称分布和细胞极性。其中一种行为是蓝细菌的光趋性，它依赖于 IV 型菌毛运动蛋白对光的动态定位。在蓝藻集胞藻中，各种信号系统包括与趋化性相关的 CheY-和 PatA 样响应调节剂，是根据光强度和波长在正趋光性和负趋光性之间切换的关键因素。在这项研究中，我们表明 PatA 型调节剂是从化学感觉系统进化而来的。通过荧光显微镜和酵母双杂交分析，我们证明它们定位于内膜，在那里它们与 PilC 的 N 端细胞质结构域和菌毛组装 ATP 酶 PilB1 相互作用。通过分别表达响应调节剂 PixE 的亚结构域，我们证实只有 N 端 PATAN 结构域与 PilB1 相互作用，定位于膜上，并且足以反转光趋性方向。这些实验确立了 PATAN 结构域是 PatA 型调节剂的主要输出结构域，我们推测它通过与菌毛运动蛋白成分结合来调节菌毛延伸。
