PMID:20453092

Citation	Nováková, L, Bezousková, S, Pompach, P, Spidlová, P, Sasková, L, Weiser, J and Branny, P (2010) Identification of multiple substrates of the StkP Ser/Thr protein kinase in Streptococcus pneumoniae. J. Bacteriol. 192:3629-38
Abstract	Monitoring the external environment and responding to its changes are essential for the survival of all living organisms. The transmission of extracellular signals in prokaryotes is mediated mainly by two-component systems. In addition, genomic analyses have revealed that many bacteria contain eukaryotic-type Ser/Thr protein kinases. The human pathogen Streptococcus pneumoniae encodes 13 two-component systems and has a single copy of a eukaryotic-like Ser/Thr protein kinase gene designated stkP. Previous studies demonstrated the pleiotropic role of the transmembrane protein kinase StkP in pneumococcal physiology. StkP regulates virulence, competence, and stress resistance and plays a role in the regulation of gene expression. To determine the intracellular signaling pathways controlled by StkP, we used a proteomic approach for identification of its substrates. We detected six proteins phosphorylated on threonine by StkP continuously during growth. We identified three new substrates of StkP: the Mn-dependent inorganic pyrophosphatase PpaC, the hypothetical protein spr0334, and the cell division protein DivIVA. Contrary to the results of a previous study, we did not confirm that the alpha-subunit of RNA polymerase is a target of StkP. We showed that StkP activation and substrate recognition depend on the presence of a peptidoglycan-binding domain comprising four extracellular penicillin-binding protein- and Ser/Thr kinase-associated domain (PASTA domain) repeats. We found that StkP is regulated in a growth-dependent manner and likely senses intracellular peptidoglycan subunits present in the cell division septa. In addition, stkP inactivation results in cell division defects. Thus, the data presented here suggest that StkP plays an important role in the regulation of cell division in pneumococcus.
Links	PubMed PMC2897338 Online version:10.1128/JB.01564-09
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Cell Division/physiology; Cloning, Molecular; Gene Expression Regulation, Bacterial/physiology; Gene Expression Regulation, Enzymologic/physiology; Protein-Serine-Threonine Kinases/genetics; Protein-Serine-Threonine Kinases/metabolism; Streptococcus pneumoniae/enzymology; Substrate Specificity
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STREE:B0BD08		GO:0004674: protein serine/threonine kinase activity	ECO:0000315:		F		Mutant Phenotype was inferred based on Figure 1: Detection of in vivo phosphorylated proteins in S. pneumoniae. Cell lysates from cultures of a wild-type strain of S. pneumoniae (Sp1) and a ΔstkP mutant strain (Sp10) were immuno-labeled and the patterns of phosphorylated proteins in the cytoplasmic and membrane fractions were compared. The anti-pThr antibody reacted with at least six protein bands in the wild type; however, no phosphorylated proteins were detected in the Sp10 strain. This result indicated that phosphorylation on Thr residues in S. pneumoniae is dependent on the presence of StkP.	complete CACAO 4559
STREE:B0BD08	enables	GO:0004674: protein serine/threonine kinase activity	ECO:0000315: mutant phenotype evidence used in manual assertion		F		Seeded From UniProt	complete

References

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