Respiration control of multicellularity in Bacillus subtilis by a complex of the cytochrome chain with a membrane-embedded histidine kinase
Respiration control of multicellularity in Bacillus subtilis by a complex of the cytochrome chain with a membrane-embedded histidine kinase
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DOI：
10.1101/gad.215244.113
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发表时间：
2013-04-15
影响因子：
10.5
通讯作者：
Losick, Richard
中科院分区：
文献类型：
--
作者：
Kolodkin-Gal, Ilana;Elsholz, Alexander K. W.;Losick, Richard
枯草芽孢杆菌形成被称为生物膜的有组织的多细胞群落，其中单个细胞通过自身产生的细胞外基质保持在一起。促进基质合成的环境信号在很大程度上仍然未知。我们发现一个这样的信号是呼吸受损。具体地说，高氧水平抑制细胞外基质的合成。相比之下，低氧水平，在没有替代电子受体的情况下，导致基质产量增加。在缺乏细胞色素caa（3）和bc的突变体中，对呼吸受损的反应被阻断，而在缺乏激酶KinB的突变体中，呼吸受损的反应显著降低。与KinB相关的蛋白质的质谱分析表明，该激酶与有氧呼吸链的多个组分形成复合物。我们建议，KinB是通过氧化还原开关激活的，涉及其第二跨膜段与一个或多个细胞色素的相互作用，在减少电子传递的条件下。此外，第二种激酶（KinA）有助于对呼吸受损的反应。有证据表明，通过以PAS结构域A依赖性方式将NAD（+）结合至激酶，烟酰胺腺嘌呤二核苷酸（NAD（+））/NADH比率降低可激活KinA。因此，B。枯草芽孢杆菌通过两条独立响应呼吸受损条件的途径从单细胞状态转换为多细胞状态。
Bacillus subtilis forms organized multicellular communities known as biofilms wherein the individual cells are held together by a self-produced extracellular matrix. The environmental signals that promote matrix synthesis remain largely unknown. We discovered that one such signal is impaired respiration. Specifically, high oxygen levels suppressed synthesis of the extracellular matrix. In contrast, low oxygen levels, in the absence of an alternative electron acceptor, led to increased matrix production. The response to impaired respiration was blocked in a mutant lacking cytochromes caa(3) and bc and markedly reduced in a mutant lacking kinase KinB. Mass spectrometry of proteins associated with KinB showed that the kinase was in a complex with multiple components of the aerobic respiratory chain. We propose that KinB is activated via a redox switch involving interaction of its second transmembrane segment with one or more cytochromes under conditions of reduced electron transport. In addition, a second kinase (KinA) contributes to the response to impaired respiration. Evidence suggests that KinA is activated by a decrease in the nicotinamide adenine dinucleotide (NAD(+))/NADH ratio via binding of NAD(+) to the kinase in a PAS domain A-dependent manner. Thus, B. subtilis switches from a unicellular to a multicellular state by two pathways that independently respond to conditions of impaired respiration.