Zipper-like interaction between proteins in adjacent daughter cells mediates protein localization
Zipper-like interaction between proteins in adjacent daughter cells mediates protein localization
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DOI：
10.1101/gad.1252704
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发表时间：
2004-12-01
影响因子：
10.5
通讯作者：
Pogliano, K
中科院分区：
文献类型：
--
作者：
Blaylock, B;Jiang, X;Pogliano, K
蛋白质定位对于细胞形态发生和细胞内信号转导级联至关重要。在这里，我们描述了两个膜蛋白表达在不同的细胞的枯草芽孢杆菌孢子囊，母细胞蛋白SpoIIIAH和前孢子蛋白SpoIIQ之间的相互作用。我们使用亲和层析，免疫共沉淀，酵母双杂交系统，以证明这些蛋白质的胞外结构域相互作用，拴SpoIIIAH的孢子形成隔膜，并指导其组装SpoIIQ成螺旋弧和焦点周围的前孢子。我们还证明，这种相互作用可以指导蛋白质在同一个细胞中的活跃分裂位点，当SpoIIQ是在母细胞中，它定位于新生的隔膜在SpoIIIAH依赖的方式。SpoIIIAH和SpollQ都是吞噬后第二个前孢子特异性转录因子（sigma（G））激活所必需的，我们认为SpoIIIAH-SpoIIQ复合物有助于将sigma（G）激活与吞噬偶联的形态检查点。与此假设一致，SpolIAH定位取决于吞噬的第一步，隔膜变薄。SpoIIQ-SpoIIIAH复合物从母细胞细胞质到达前孢子细胞质，并且理想地定位于控制吞噬依赖性转录因子的活性。
Protein localization is crucial for cellular morphogenesis and intracellular signal transduction cascades. Here we describe an interaction between two membrane proteins expressed in different cells of the Bacillus subtilis sporangium, the mother cell protein SpoIIIAH and the forespore protein SpoIIQ. We used affinity chromatography, coimmunoprecipitation, and the yeast two-hybrid system to demonstrate that the extracellular domains of these proteins interact, tethering SpoIIIAH to the sporulation septum, and directing its assembly with SpoIIQ into helical arcs and foci around the forespore. We also demonstrate that this interaction can direct proteins made in the same cell to active division sites, as when SpoIIQ is made in the mother cell, it localizes to nascent septa in a SpoIIIAH-dependent manner. Both SpoIIIAH and SpollQ are necessary for activation of the second forespore-specific transcription factor (sigma(G)) after engulfment, and we propose that the SpoIIIAH-SpoIIQ complex contributes to a morphological checkpoint coupling sigma(G) activation to engulfment. In keeping with this hypothesis, SpolIlAH localization depends on the first step of engulfment, septal thinning. The SpoIIQ-SpoIIIAH complex reaches from the mother cell cytoplasm to the forespore cytoplasm and is ideally positioned to govern the activity of engulfment-dependent transcription factors.