Serine/Threonine Protein Kinase SpkA in Synechocystis sp. Strain PCC 6803 Is a Regulator of Expression of Three Putative pilA Operons, Formation of Thick Pili, and Cell Motility

Previous studies showed that a Ser/Thr protein kinase, SpkA, in Synechocystis sp. strain PCC 6803 is involved in cell motility. The present study, in which DNA microarray analysis and electron microscopy were used, demonstrated that SpkA regulates the expression of putative pilA9-pilA10-pilA11-slr2018, pilA5-pilA6, and pilA1-pilA2 operons and is essential for the formation of thick pili.