Targets of kinase/phosphatase signaling pair StkP/PhpP in S. pneumoniae and their involvement in response to cell wall stress

To identify targets of kinase/phosphatase signalling pair StkP/PhpP we decided to compare phosphoproteome of the wild type (WT), delta stkP (Sp10), stkP-K42A (Sp294) and delta phpP (Sp113) strain in Rx1 genetic background (SpnRx1). It has previously been reported that long-term passage of delta stkP strains in different genetic backgrounds resulted in a loss of the characteristic elongated-cell phenotype, probably due to the accumulation of suppressor mutations in the genome. To exclude the possibility that the analyzed stkP mutated strains might carry an unlinked extragenic suppressor, corresponding strains were prepared de novo and subjected to whole-genome sequencing.