Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, United States of America.
Department of Biology, Indiana University, Bloomington, Indiana, United States of America.
PLoS Genet. 2013;9(12):e1004002. doi: 10.1371/journal.pgen.1004002. Epub 2013 Dec 19.
Genomic and genetic analyses have demonstrated that many species contain multiple chemotaxis-like signal transduction cascades that likely control processes other than chemotaxis. The Che₃ signal transduction cascade from Rhodospirillum centenum is one such example that regulates development of dormant cysts. This Che-like cascade contains two hybrid response regulator-histidine kinases, CheA₃ and CheS₃, and a single-domain response regulator CheY₃. We demonstrate that cheS₃ is epistatic to cheA₃ and that only CheS₃∼P can phosphorylate CheY₃. We further show that CheA₃ derepresses cyst formation by phosphorylating a CheS₃ receiver domain. These results demonstrate that the flow of phosphate as defined by the paradigm E. coli chemotaxis cascade does not necessarily hold true for non-chemotactic Che-like signal transduction cascades.
基因组和遗传分析表明，许多物种包含多个类似趋化性的信号转导级联，这些级联可能控制着除趋化性以外的其他过程。来自 Centenum 的 Rhodospirillum 的 Che₃ 信号转导级联就是这样一个调节休眠囊泡发育的例子。这个 Che 样级联包含两个混合的响应调节子-组氨酸激酶，CheA₃ 和 CheS₃，和一个单域响应调节子 CheY₃。我们证明 cheS₃ 是 cheA₃ 的上位基因，并且只有 CheS₃∼P 可以磷酸化 CheY₃。我们进一步表明，CheA₃ 通过磷酸化 CheS₃ 受体域来解除对囊泡形成的抑制。这些结果表明，磷酸的流动并不一定符合大肠杆菌趋化性级联的范例，对于非趋化性的 Che 样信号转导级联也是如此。
