Activation of extracytoplasmic function sigma factors upon removal of glucolipids and reduction of phosphatidylglycerol content in Bacillus subtilis cells lacking lipoteichoic acid
2019
Seki, T. (Saitama University, Saitama, Saitama (Japan). Graduate School of Science and Engineering, Department of Biochemistry and Molecular Biology) | Furumi, T. | Hashimoto, M. | Hara, H. | Matsuoka, S.
In Bacillus subtilis, extracytoplasmic function (ECF) sigma factors are activated by reduction of phosphatidylglycerol (PG) content, absence of glucolipids, or absence of lipoteichoic acid (LTA). LTA is synthesized by polymerization of the glycerophosphate moiety of PG onto diglucosyldiacylglycerol (DGlcDG), a major glucolipid in B. subtilis, in the plasma membrane. Thus, reduction of PG content or absence of glucolipids might cause some changes in LTA, and hence we investigated whether reduction of PG content or absence of glucolipids induces the activation of ECF sigma factors independently from an ensuing change in LTA. Disruption of ugtP, responsible for glucolipid synthesis, in cells lacking LTA caused an additive increase of activation levels of σsup(M), σsup(X), σsup(V), and σsup(Y), (3.1-, 2.2-, 2.1- and 1.4-fold, respectively), relative to their activation levels in cells lacking LTA alone. Reduction of PG content (by repressing Psub(spac)-pgsA) in the cells lacking LTA caused an additive increase of activation levels of σsup(M), σsup(W) and σsup(V) (2.3-, 1.9- and 2.2-fold, respectively). These results suggested that absence of glucolipids or reduction of PG alone, not the possible secondary alteration in LTA, leads to changes that affect the regulation systems of some ECF sigma factors in the plasma membrane.
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