Tyrosine phosphorylation and bacterial virulence

Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria.In this article,we review the structure and function of bacterial tyrosine kinases and phosphatases.Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes(bacterial tyrosine(BY) kinases) that are characterized by the presence of Walker motifs.The reverse reaction is catalyzed by three classes of enzymes:the eukaryotic-like phosphatases(PTPs) and dual-specific phosphatases;the low molecular weight protein-tyrosine phosphatases(LMW-PTPs);and the polymerase-histidinol phosphatases(PHP).Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates,thereby contributing to bacterial pathogenicity.Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development.The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii.Ltp1 is upregulated by contact with S.gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.