Abstract：
During spore development in bacteria, a polar septum separates two transcriptionally distinct cellular compartments, the mother cell and the forespore. The conserved serine phosphatase SpoIIE is known for its critical role in the formation of this septum and activation of compartment-specific transcription in the forespore. Signaling between the mother cell and forespore then leads to activation of mother cell transcription and a phagocytic-like process called engulfment, which involves dramatic remodeling of the septum and requires a balance between peptidoglycan synthesis and hydrolysis to ensure septal stability and compartmentalization. Using Bacillus subtilis, we identify an additional role for SpoIIE in maintaining septal stability and compartmentalization at the onset of engulfment. This role for SpoIIE is mediated by SpoIIQ, which anchors SpoIIE in the engulfing membrane. A SpoIIQ mutant (SpoIIQ Y28A) that fails to anchor SpoIIE, results in septal instability and miscompartmentalization during septal peptidoglycan hydrolysis, when other septal stabilization factors are absent. Our data support a model whereby SpoIIE and its interactions with the peptidoglycan synthetic machinery contribute to the stabilization of the asymmetric septum early in engulfment, thereby ensuring compartmentalization during spore development.IMPORTANCEBacterial sporulation is a complex process involving a vast array of proteins. Some of these proteins are absolutely critical and regulate key points in the developmental process. Once such protein is SpoIIE, known for its role in the formation of the polar septum, a hallmark of the early stages of sporulation, and activation of the first sporulation-specific sigma factor, σF, in the developing spore. Interestingly, SpoIIE has been shown to interact with SpoIIQ, an important σF-regulated protein that functions during the engulfment stage. However, the significance of this interaction has remained unclear. Here, we unveil the importance of the SpoIIQ-SpoIIE interaction and identify a role for SpoIIE in the stabilization of the polar septum and maintenance of compartmentalization at the onset of engulfment. In this way, we demonstrate that key sporulation proteins, like SpoIIQ and SpoIIE, function in multiple processes during spore development.
摘要：
在细菌孢子发育过程中，极隔分隔两个转录上不同的细胞区室，母细胞和前孢子。保守的丝氨酸磷酸酶SpoIIE以其在该隔膜的形成和前孔中隔室特异性转录的激活中的关键作用而闻名。母细胞和前孢子之间的信号然后导致母细胞转录的激活和被称为吞噬的吞噬样过程，这涉及隔膜的戏剧性重塑，需要肽聚糖合成和水解之间的平衡，以确保隔膜的稳定性和分隔。使用枯草芽孢杆菌,我们确定了SpoIIE在吞噬开始时维持间隔稳定性和隔室化方面的额外作用。Spotify的这一作用是由Spotify介导的，将SpoIIE固定在吞噬膜中。一个未能锚定斯波伊的斯波伊克突变体(斯波伊克Y28A),在间隔肽聚糖水解过程中导致间隔不稳定和错室化，当缺乏其他间隔稳定因素时。我们的数据支持一个模型，通过该模型，SpoIIE及其与肽聚糖合成机制的相互作用有助于在吞噬早期稳定不对称隔膜，从而确保孢子发育过程中的区隔。重要细菌孢子形成是涉及大量蛋白质的复杂过程。这些蛋白质中的一些是绝对关键的，并调节发育过程中的关键点。一旦这样的蛋白质是Spotify,以其在极隔形成中的作用而闻名，孢子形成早期阶段的标志，和第一个孢子形成特异性σ因子的激活，σF,在发育中的孢子中。有趣的是,Spotify已经被证明与Spotify互动，一种重要的σF调节蛋白，在吞噬阶段起作用。然而,这种相互作用的意义尚不清楚.这里,我们揭示了spoIIQ-spoIIE相互作用的重要性,并确定spoIIE在极隔的稳定和吞噬开始时的分隔维持中的作用.这样,我们证明了关键的孢子形成蛋白，比如Spotify和Spotify,在孢子发育过程中的多个过程中发挥作用。
