Galyov E E, Håkansson S, Forsberg A, Wolf-Watz H
Department of Cell and Molecular Biology, University of Umeå, Sweden.
Nature. 1993 Feb 25;361(6414):730-2. doi: 10.1038/361730a0.
Phosphorylation of proteins catalysed by protein kinases is associated with central functions in growth and proliferation of the eukaryotic cell, and kinases are particularly important in the signal transduction pathways. Enterobacterial protein kinases are structurally and functionally different from eukaryotic protein kinases, and no prokaryotic kinase has so far been described implicating a direct role for this activity in virulence. Virulent Yersinia possess a common virulence plasmid that encodes a number of secreted proteins (Yops), of which YopH has protein-tyrosine phosphatase activity with a key function in the block of phagocytosis by the pathogen. Here we report that the virulence plasmid of Yersinia pseudotuberculosis encodes a secreted protein kinase (YpkA) with extensive homology to eukaryotic Ser/Thr protein kinases. Specific mutants of ypkA resulted in avirulent strains. Thus, YpkA is, to our knowledge, the first reported prokaryotic secreted protein kinase involved in pathogenicity, presumably by interfering with the signal transduction pathways of the target cell.
由蛋白激酶催化的蛋白质磷酸化与真核细胞生长和增殖的核心功能相关，并且激酶在信号转导途径中尤为重要。肠道细菌的蛋白激酶在结构和功能上与真核蛋白激酶不同，迄今为止，尚未有原核激酶被描述在毒力方面具有这种活性的直接作用。致病性耶尔森菌拥有一个共同的毒力质粒，该质粒编码多种分泌蛋白（Yops），其中YopH具有蛋白酪氨酸磷酸酶活性，在病原体阻断吞噬作用中起关键作用。在此我们报告，假结核耶尔森菌的毒力质粒编码一种与真核丝氨酸/苏氨酸蛋白激酶具有广泛同源性的分泌蛋白激酶（YpkA）。ypkA的特定突变体产生无毒力菌株。因此，据我们所知，YpkA是首个被报道参与致病性的原核分泌蛋白激酶，可能是通过干扰靶细胞的信号转导途径来实现的。
