Tyrosine phosphorylation enhances activity of pneumococcal autolysin LytA

Abstract

Tyrosine phosphorylation has long been recognized as a crucial post-translational regulatory mechanism in eukaryotes. However, only in the past decade has recognition been given to the crucial importance of bacterial tyrosine phosphorylation as an important regulatory feature of pathogenesis. This study describes the effect of tyrosine phosphorylation on the activity of a major virulence factor of the pneumococcus, the autolysin LytA, and a possible connection to the Streptococcus pneumoniae capsule synthesis regulatory proteins (CpsB, CpsC and CpsD). We show that in vitro pneumococcal tyrosine kinase, CpsD, and the protein tyrosine phosphatase, CpsB, act to phosphorylate and dephosphorylate LytA. Furthermore, this modulates LytA function in vitro with phosphorylated LytA binding more strongly to the choline analogue DEAE. A phospho-mimetic (Y264E) mutation of the LytA phosphorylation site displayed similar phenotypes as well as an enhanced dimerization capacity. Similarly, tyrosine phosphorylation increased LytA amidase activity, as evidenced by a turbidometric amidase activity assay. Similarly, when the phospho-mimetic mutation was introduced in the chromosomal lytA of S. pneumoniae, autolysis occurred earlier and at an enhanced rate. This study thus describes, to our knowledge, the first functional regulatory effect of tyrosine phosphorylation on a non-capsule-related protein in the pneumococcus, and suggests a link between the regulation of LytA-dependent autolysis of the cell and the biosynthesis of capsular polysaccharide.

Proteomic Adaptation of Streptococcus pneumoniae to the Human Antimicrobial Peptide LL-37

“…Probably for the same reason, LytA was not found to be enriched even when the involvement of this enzyme in LL-37 resistance was described for pneumococci [16]. In fact, LytA activation is regulated by phosphorylation [55], and this could also be the case in this study.…”

The Tyrosine-Autokinase UbK Is Required for Proper Cell Growth and Cell Morphology of Streptococcus pneumoniae

“…On the other hand, phosphorylation on tyrosine is mainly achieved by the bacterial idiosyncratic protein-tyrosine kinase family BY-kinases (Bacterial tyrosine kinases) (Grangeasse et al, 2007; Jadeau et al, 2008; Mijakovic et al, 2016). Like eSTKs, BY-kinases regulate several biological processes and their best studied function concerns their role in the biosynthesis and export of extracellular polysaccharides (Standish et al, 2014; Nourikyan et al, 2015; Mijakovic et al, 2016). They are also widely conserved in bacterial genomes and most of bacterial species encode for at least one BY-kinase (Jadeau et al, 2012).…”

Role of Streptococcus pneumoniae OM001 operon in capsular polysaccharide production, virulence and survival in human saliva

“…Markerless, non-polar mutant strains were constructed in a serotype 2 D39 streptomycin resistant strain and serotype 3 WU2 streptomycin resistant strain essentially as previously described [ 8 ]. First, the Janus cassette was used to target and replace the spd1837 operon region in D39 and WU2 background strains [ 23 ].…”

“…Much of our work has previously focused on determining the role that tyrosine phosphorylation plays in the virulence of S . pneumoniae [ 5 – 8 ]. We have recently characterized Spd1837 as a protein tyrosine phosphatase (PTP) of the Low Molecular Weight Protein Tyrosine Phosphatase family (LMWPTP) that may interact with proteins associated with pneumococcal metabolism (Ahmad et .…”