1. A protein phosphorylation module patterns the Bacillus subtilis spore outer coat
- Author
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Rita Zilhão, Ezio Ricca, Assunta Pelosi, Carolina Freitas, Loredana Baccigalupi, Alexander K. W. Elsholz, Richard Losick, Jarnaja Plannic, Rachele Isticato, Mónica Serrano, Adriano O. Henriques, Freitas, C., Plannic, J., Isticato, R., Pelosi, A., Zilhao, R., Serrano, M., Baccigalupi, L., Ricca, E., Elsholz, A. K. W., Losick, R., and O. Henriques, A.
- Subjects
Coat ,Morphogenesis ,Bacillus subtilis ,Microbiology ,03 medical and health sciences ,CotB ,Bacterial Proteins ,Cell Wall ,Protein phosphorylation ,CotG ,Amino Acid Sequence ,CotH ,Phosphorylation ,Protein kinase A ,Molecular Biology ,Research Articles ,spore coat ,030304 developmental biology ,Sequence Deletion ,Spores, Bacterial ,0303 health sciences ,Strain (chemistry) ,biology ,Chemistry ,030306 microbiology ,Kinase ,fungi ,protein kinase ,biology.organism_classification ,Spore ,Cell biology ,protein phosphorylation ,Research Article - Abstract
Assembly of the Bacillus subtilis spore coat involves over 80 proteins which self‐organize into a basal layer, a lamellar inner coat, a striated electrodense outer coat and a more external crust. CotB is an abundant component of the outer coat. The C‐terminal moiety of CotB, SKRB, formed by serine‐rich repeats, is polyphosphorylated by the Ser/Thr kinase CotH. We show that another coat protein, CotG, with a central serine‐repeat region, SKRG, interacts with the C‐terminal moiety of CotB and promotes its phosphorylation by CotH in vivo and in a heterologous system. CotG itself is phosphorylated by CotH but phosphorylation is enhanced in the absence of CotB. Spores of a strain producing an inactive form of CotH, like those formed by a cotG deletion mutant, lack the pattern of electrondense outer coat striations, but retain the crust. In contrast, deletion of the SKRB region, has no major impact on outer coat structure. Thus, phosphorylation of CotG by CotH is a key factor establishing the structure of the outer coat. The presence of the cotB/cotH/cotG cluster in several species closely related to B. subtilis hints at the importance of this protein phosphorylation module in the morphogenesis of the spore surface layers., CotB and CotG are abundant components of the Bacillus subtilis spore coat, both possessing a series of serine‐/lysine‐rich repeats (SKR). CotG interacts with CotB promoting its polyphosphorylation in the SKR region by the CotH kinase. CotG, itself phosphorylated by CotH, is a key determinant of the striated pattern of the outer coat. Conservancy of the cotB/cotH/cotG cluster suggests that protein phosphorylation is an important mechanism in the morphogenesis of the spore surface across species.
- Published
- 2020