chain length, a virulence determinant, is regulated by membrane localized serine/threonine protein kinase PrkC.

Anthrax is a zoonotic disease caused by , a spore-forming pathogen that displays a chaining phenotype. It has been reported that the chaining phenotype acts as a virulence factor in In this study, we identify a serine/threonine protein kinase of , PrkC, the only kinase localized at the bacteria-host interface, as a determinant of chain length. , disruption strain (BAS Δ) grew as shorter chains throughout the bacterial growth cycle. A comparative analysis between the parent strain and BAS Δ indicated that the levels of proteins, BslO and Sap, associated with the regulation of the bacterial chain length, were upregulated in BAS Δ BslO is a septal murein hydrolase that catalyzes daughter cell separation and Sap is an S-layer structural protein required for the septal localization of BslO. PrkC disruption also has a significant effect on bacterial growth, cell wall thickness, and septa formation. Upregulation of in BAS Δ was also observed. Altogether, our results indicate that PrkC is required for maintaining optimum growth, cell wall homeostasis and most importantly - for the maintenance of the chaining phenotype.Chaining phenotype acts as a virulence factor in This is the first study that identifies a 'signal transduction protein' with an ability to regulate the chaining phenotype in We show that the disruption of the lone surface-localized serine/threonine protein kinase, PrkC, leads to the shortening of the bacterial chains. We report upregulation of the de-chaining proteins in the PrkC disruption strain. Apart from this, we also report for the first time that PrkC disruption results in an attenuated cell growth, a decrease in the cell wall thickness and aberrant cell septa formation during the logarithmic phase of growth - a growth phase where PrkC is expressed maximally.