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Characterization of a membrane‐linked Ser/Thr protein kinase in Bacillus subtilis , implicated in developmental processes
Author(s) -
Madec Edwige,
Laszkiewicz Agnieszka,
Iwanicki Adam,
Obuchowski Michal,
Séror Simone
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.03178.x
Subject(s) - biology , bacillus subtilis , mutant , threonine , repressor , kinase , microbiology and biotechnology , phosphorylation , biochemistry , phosphatase , serine , protein kinase domain , transmembrane protein , subcellular localization , cytoplasm , receptor , gene , genetics , bacteria , transcription factor
Summary PrkC was shown to be a eukaryotic‐like (Hanks‐type) protein kinase from Bacillus subtilis with a struc‐tural organization similar to that of the eukaryotic sensor Ser/Thr or Tyr kinases (e.g. the TGF β or PDGF receptors). The molecule consists of a catalytic domain located in the cytoplasm, joined by a single transmembrane‐spanning region (TMD) to a large extracellular domain. Using a genetic reporter system, involving the cI repressor of lambda, evidence was obtained indicating that PrkC forms a dimer, involving both the TMD and the external domain in dimerization. The purified catalytic domain of PrkC was shown to autophosphorylate and to phosphorylate an external target, MBP, in both cases on threonine. These two functions require the completely conserved K40 residue in subdomain II, which is essential for enzymatic activity. Importantly, both the mutant deleted for prkC and a K40R mutant exhibit decreased efficiency of sporulation and a significant reduction in biofilm formation, demonstrating that the catalytic activity of PrkC is necessary for these two developmental processes. In addition, we showed that the product of prpC , a PPM phosphatase encoded by the adjacent gene, co‐transcribed with prkC , is also required for normal biofilm and spore formation.