A network of filament-forming proteins maintains multicellular shape in the cyanobacterium Anabaena sp. PCC 7120
A network of filament-forming proteins maintains multicellular shape in the cyanobacterium Anabaena sp. PCC 7120
复制标题
DOI：
10.1101/553073
复制
发表时间：
2019-02
期刊：
影响因子：
--
通讯作者：
B. L. Springstein;Dennis J. Nürnberg;Ann-Katrin Kieninger;Christian Woehle;Julia Weissenbach;Marius Theune;A. Helbig;A. Tholey;I. Maldener;Tal Dagan;Karina Stucken
中科院分区：
文献类型：
--
作者：
B. L. Springstein;Dennis J. Nürnberg;Ann-Katrin Kieninger;Christian Woehle;Julia Weissenbach;Marius Theune;A. Helbig;A. Tholey;I. Maldener;Tal Dagan;Karina Stucken
细菌细胞形状的决定因素在单细胞形式中被广泛研究。尽管如此，形成细菌多细胞形式的机制仍未得到充分研究。在这里，我们研究了多细胞蓝藻鱼腥藻中的富卷曲蛋白(CCRPs)。PCC 7120(以下简称鱼腥藻)。我们的结果揭示了两个CCPRs，Alr4504和Alr4505(称为LFIA和LfiB，用于线性细丝)，它们在体内和体外组装成一种杂聚聚合物。另外两个CCRPs，Alr0931(Cyps为蓝藻极地支架)和All2460(蓝藻伸长体相关调节因子)，分别形成了一个极性蛋白质支架，并与MreB活性相关。这些CCRP的缺失突变体的特征是毛状体(即蓝藻细丝)和细胞形状受损，活力下降。4个CCRPs均与MreB相互作用，除Cyps外，其余均与MreB相互作用。我们的结果表明，蓝藻中存在细丝形成的CCRPs，它们可能与SepJ和MreB合作，形成稳定鱼腥藻毛发的蛋白质网络。我们认为这个网络对于鱼腥藻中线性毛状体表型的表现是必不可少的。重要性蓝藻门的特征是形态多样性很大，从球状或杆状的单细胞物种到形成多细胞形态的物种，这些物种由几个连接成线性形式的细胞组成。尽管有这种多样性，但人们对蓝藻形态多样性的分子机制知之甚少。其中，细胞骨架蛋白FtsZ和MreB是蓝藻细胞形态和活力的重要调节因子。蓝藻的多细胞表型也与隔膜连接有关，隔膜连接包括一个虚假的复合体，以线性形式在相邻细胞之间分裂。在我们的研究中，我们鉴定并鉴定了四种参与多细胞蓝藻细胞和毛状体形状调节的蛋白质。我们发现这些蛋白质中的两个相互依赖于聚合，揭示了原核细丝形成蛋白的一个新特征。我们的研究使我们对蓝藻形态多样性的基本原理有了更广泛的理解。
The determinants of bacterial cell shape are extensively studied in unicellular forms. Nonetheless, the mechanisms that shape bacterial multicellular forms remain understudied. Here we study coiled-coil rich proteins (CCRPs) in the multicellular cyanobacterium Anabaena sp. PCC 7120 (hereafter Anabaena). Our results reveal two CCPRs, Alr4504 and Alr4505 (termed LfiA and LfiB for linear filament), which assemble into a heteropolymer in vivo and in vitro. Two additional CCRPs, Alr0931 (termed CypS for cyanobacterial polar scaffold) and All2460 (termed CeaR for cyanobacterial elongasome associated regulator), form a polar proteinaceous scaffold and are associated with MreB activity, respectively. Deletion mutants of these CCRPs are characterized by impaired trichome (i.e. cyanobacterial filament) and cell shape and decreased viability. All four CCRPs interacted with each other, with the septal junction protein SepJ and all but CypS interacted with MreB. Our results indicate that filament-forming CCRPs are present in cyanobacteria and that they, likely in cooperation with SepJ and MreB, could form a proteinaceous network that stabilizes the Anabaena trichome. We propose that this network is essential for the manifestation of the linear trichome phenotype in Anabaena. Importance The phylum Cyanobacteria is characterized by a large morphological diversity, ranging from coccoid or rod-shaped unicellular species to species forming multicellular morphology, which comprise several cells connected into a linear form. Despite this diversity, very few molecular mechanisms underlying the cyanobacterial morphological diversity are known. Among these, the cytoskeletal proteins FtsZ and MreB are important regulators of cyanobacterial cell shape and viability. The multicellular phenotype of cyanobacteria has been linked also to the septal junctions, which comprise a pretentious complex dividing between neighboring cells in the linear form. In our research we identified and characterized four proteins that are involved in cell and trichome shape regulation in multicellular cyanobacteria. We show that two of those proteins are interdependent for polymerization, revealing a novel feature for prokaryotic filament-forming proteins. Our study leads to a broader understanding of the underlying principles of cyanobacterial morphological diversity.