Control of Morphological Differentiation of Streptomyces coelicolor A3(2) by Phosphorylation of MreC and PBP2

• Published in: PloS one Vol. 10; no. 4; p. e0125425
• Main Authors: Ladwig, Nils, Franz-Wachtel, Mirita, Hezel, Felix, Soufi, Boumediene, Macek, Boris, Wohlleben, Wolfgang, Muth, Günther
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.04.2015; Public Library of Science (PLoS)
• Subjects: Aberration; Analysis; Antibiotics; Bacillus subtilis; Bacteria; Bacterial Proteins - metabolism; Clusters; Defects; Differentiation; E coli; Escherichia coli - metabolism; Escherichia coli Proteins - metabolism; Gene Expression Regulation, Bacterial; Hyphae; Kinases; Penicillin-Binding Proteins - metabolism; Phosphorylation; Phosphotransferases; Protein Binding; Protein kinase; Protein-serine/threonine kinase; Proteins; Spores; Spores, Bacterial - metabolism; Sporulation; Streptomyces; Streptomyces coelicolor; Streptomyces coelicolor - cytology; Streptomyces coelicolor - metabolism; Synthesis; Tandem Mass Spectrometry; Threonine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0125425

During morphological differentiation of Streptomyces coelicolor A3(2), the sporogenic aerial hyphae are transformed into a chain of more than fifty spores in a highly coordinated manner. Synthesis of the thickened spore envelope is directed by the Streptomyces spore wall synthesizing complex SSSC which resembles the elongasome of rod-shaped bacteria. The SSSC includes the eukaryotic type serine/threonine protein kinase (eSTPK) PkaI, encoded within a cluster of five independently transcribed eSTPK genes (SCO4775-4779). To understand the role of PkaI in spore wall synthesis, we screened a S. coelicolor genomic library for PkaI interaction partners by bacterial two-hybrid analyses and identified several proteins with a documented role in sporulation. We inactivated pkaI and deleted the complete SCO4775-4779 cluster. Deletion of pkaI alone delayed sporulation and produced some aberrant spores. The five-fold mutant NLΔ4775-4779 had a more severe defect and produced 18% aberrant spores affected in the integrity of the spore envelope. Moreover, overbalancing phosphorylation activity by expressing a second copy of any of these kinases caused a similar defect. Following co-expression of pkaI with either mreC or pbp2 in E. coli, phosphorylation of MreC and PBP2 was demonstrated and multiple phosphosites were identified by LC-MS/MS. Our data suggest that elaborate protein phosphorylation controls activity of the SSSC to ensure proper sporulation by suppressing premature cross-wall synthesis.