PMID:18442973

Citation	Fiuza, M, Canova, MJ, Zanella-Cléon, I, Becchi, M, Cozzone, AJ, Mateos, LM, Kremer, L, Gil, JA and Molle, V (2008) From the characterization of the four serine/threonine protein kinases (PknA/B/G/L) of Corynebacterium glutamicum toward the role of PknA and PknB in cell division. J. Biol. Chem. 283:18099-112
Abstract	Corynebacterium glutamicum contains four serine/threonine protein kinases (STPKs) named PknA, PknB, PknG, and PknL. Here we present the first biochemical and comparative analysis of all four C. glutamicum STPKs and investigate their potential role in cell shape control and peptidoglycan synthesis during cell division. In vitro assays demonstrated that, except for PknG, all STPKs exhibited autokinase activity. We provide evidence that activation of PknG is part of a phosphorylation cascade mechanism that relies on PknA activity. Following phosphorylation by PknA, PknG could transphosphorylate its specific substrate OdhI in vitro. A mass spectrometry profiling approach was also used to identify the phosphoresidues in all four STPKs. The results indicate that the nature, number, and localization of the phosphoacceptors varies from one kinase to the other. Disruption of either pknL or pknG in C. glutamicum resulted in viable mutants presenting a typical cell morphology and growth rate. In contrast, we failed to obtain null mutants of pknA or pknB, supporting the notion that these genes are essential. Conditional mutants of pknA or pknB were therefore created, leading to partial depletion of PknA or PknB. This resulted in elongated cells, indicative of a cell division defect. Moreover, overexpression of PknA or PknB in C. glutamicum resulted in a lack of apical growth and therefore a coccoid-like morphology. These findings indicate that pknA and pknB are key players in signal transduction pathways for the regulation of the cell shape and both are essential for sustaining corynebacterial growth.
Links	PubMed Online version:10.1074/jbc.M802615200
Keywords	Amino Acid Sequence; Binding Sites; Cell Division; Cloning, Molecular; Corynebacterium glutamicum/metabolism; Gene Expression Regulation, Bacterial; Models, Biological; Models, Genetic; Molecular Sequence Data; Mutation; Phosphorylation; Protein-Serine-Threonine Kinases/chemistry; Protein-Serine-Threonine Kinases/physiology; Recombinant Proteins/chemistry; Sequence Homology, Amino Acid; Signal Transduction
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CORGL:PKN2	enables	GO:0016772: transferase activity, transferring phosphorus-containing groups	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
CORGL:PKN2		GO:0016772: transferase activity, transferring phosphorus-containing groups	ECO:0000314:		F		Figure 3 from the paper.	complete CACAO 3275
CORGL:PKN1		GO:0004674: protein serine/threonine kinase activity	ECO:0000247:		F		Figure 1 in text	Missing: with/from CACAO 3377
CORGL:Q6M3Q8		GO:0004674: protein serine/threonine kinase activity	IDA: Inferred from Direct Assay:	F	Figure 3 in text	complete CACAO 3376
CORGL:Q6M299		GO:0004674: protein serine/threonine kinase activity	IEP: Inferred from Expression Pattern:	F	Figure 3 in text	complete CACAO 3378

References

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