Author(s)

Takahiro Seki, Kouji Matsumoto, Satoshi Matsuoka, Hiroshi Hara^*

Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan.

Extracytoplasmic function (ECF) σ factors are a crucial link in the process of bacterial response to environmental stresses, in which bacteria transmit information across the cytoplasmic membrane. Among the seven ECF σ factors of Bacillus subtilis σ^V, which is sequestered by transmembrane anti-σ factor RsiV under normal growth conditions, responds to lysozyme. When B. subtilis cells are challenged by lysozyme, the lysozyme-bound RsiV undergoes two successive proteolysis steps, by a signal peptidase and RasP protease, and releases σ^V. An unchallenged B. subtilis ugtP mutant lacking glucolipids exhibited higher σ^V activity than wild type. However, the activation occurred in the absence of RasP, and no proteolysis of RsiV was observed. It is likely that a conformational change, not proteolysis, of RsiV leads to this activation of σ^V in the absence of glucolipids. Replacement of the C-terminal region of RsiV with that of RsiW, the cognate σ factor of which, σ^W, is not activated in the ugtP mutant, indicated that the C-terminal extracytoplasmic region of RsiV was necessary for the response to glucolipid deficiency.

Anti-σ Factor, Bacillus subtilis, ECF σ Factor, Glucolipid, RsiV, σ^V, UgtP

Seki, T. , Matsumoto, K. , Matsuoka, S. and Hara, H. (2017) Activation without Proteolysis of Anti-σ Factor RsiV of the Extracytoplasmic Function σ Factor σ^V in a Glucolipid-Deficient Mutant of Bacillus subtilis. Advances in Microbiology, 7, 315-327. doi: 10.4236/aim.2017.74026.