Two Ser/Thr protein kinases essential for efficient aggregation and spore morphogenesis in Myxococcus xanthus

摘要: Myxococcus xanthus has a complex life cycle that involves vegetative growth and development. Previously, we described the espAB locus is involved in timing events during initial stages of fruiting body formation. Deletion espA caused early aggregation sporulation, whereas deletion espB delayed sporulation resulting reduced spore yields. In this study, describe two genes, pktA5 pktB8, flank encode Ser/Thr protein kinase (STPK) homologues. Cells deficient or pktB8 formed translucent mounds produced low yields, similar many respects to mutants. Double mutant analysis revealed was epistatic with respect morphology, but were efficiency. Expression profiles pktA5-lacZ pktB8-lacZ fusions Western blot showed STPKs are expressed under developmental conditions. vitro assays demonstrated RD kinase, PktA5, autophosphorylated on threonine residue(s) phosphorylated artificial substrate, myelin basic protein. contrast, autophosphorylation non-RD PktB8, not observed vitro; however, phenotype kinase-dead point resembled mutant, indicating residue important for function it likely functions as vivo. Immunoprecipitation Tap-tagged PktA5 PktB8 an interaction EspA development M. xanthus. These results, taken together, suggest by interacting EspB regulate