Protein tyrosine phosphorylation by dual specificity kinases in M. tuberculosis

描述(申请人提供)：细胞信号普遍由可逆的蛋白质磷酸化控制。在原核生物中，组氨酸和天冬氨酸的磷酸化一直被认为是主要的信号机制，但现在丝氨酸(Ser)、苏氨酸(Thr)和酪氨酸(Tyr)的磷酸化也同样重要。在结核分枝杆菌(Mtb)中，通过丝氨酸/苏氨酸磷酸化的信号转导是必不可少的。然而，Tyr上的磷酸化还没有被描述，而且被认为是不存在的。我们现在第一次展示了Mtb蛋白酪氨酸的磷酸化。在单一的生长条件下，我们明确地检测到16种蛋白质上的25个磷酸化位点。我们显示了两个Mtb Ser/Thr激酶(STPKs)的酪氨酸磷酸化活性，这表明一些STPKs是双特异性的。此外，我们还发现Tyr的磷酸化控制着必需的STPK PKnB的整体活性。由于PKnB对结核分枝杆菌的生长是必不可少的，其他STPKs广泛地调节结核分枝杆菌的适应，而酪氨酸磷酸化决定了其他细菌的毒力，这些发现对结核分枝杆菌的发病具有广泛的意义。在这里，我们将确定介导Mtb蛋白在Tyr上磷酸化的激酶和磷酸酶。

DESCRIPTION (provided by applicant): Cell signaling is universally controlled by reversible protein phosphorylation. In prokaryotes, phosphorylation on histidine and aspartate was long considered the main signaling mechanism, but phosphorylation on serine (Ser), threonine (Thr), and tyrosine (Tyr) is now emerging as equally important. In Mycobacterium tuberculosis (Mtb), signaling through Ser/Thr phosphorylation is essential. Phosphorylation on Tyr, however, has not yet been described and is thought to be absent. We now for the first time show protein tyrosine phosphorylation in Mtb. We unambiguously detected 25 phosphorylation sites on 16 proteins in a single growth condition. We show tyrosine phosphorylation activity of two Mtb Ser/Thr kinases (STPKs), suggesting that some STPKs are dual specificity kinases. Further, we show that Tyr phosphorylation controls the overall activity of the essential STPK PknB. Because PknB is essential for Mtb growth, other STPKs broadly regulate Mtb adaptations, and tyrosine phosphorylation determines virulence in other bacteria, these findings have wide implications for Mtb pathogenesis. Here, we will identify the kinases and phosphatases that mediate Mtb protein phosphorylation on Tyr.