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Lookup NU author(s): Charlotte Roughton, Anna Barwinska-Sendra, Dr Daniela Vollmer, Dr Joseph Gray, Professor Waldemar Vollmer, Professor Paula SalgadoORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The Author(s). Molecular Microbiology published by John Wiley & Sons Ltd.In the model organism Bacillus subtilis, a signaling protease produced in the forespore, SpoIVB, is essential for the activation of the sigma factor σK, which is produced in the mother cell as an inactive pro-protein, pro-σK. SpoIVB has a second function essential to sporulation, most likely during cortex synthesis. The cortex is composed of peptidoglycan (PG) and is essential for the spore's heat resistance and dormancy. Surprisingly, the genome of the intestinal pathogen Clostridioides difficile, in which σK is produced without a pro-sequence, encodes two SpoIVB paralogs, SpoIVB1 and SpoIVB2. Here, we show that spoIVB1 is dispensable for sporulation, while a spoIVB2 in-frame deletion mutant fails to produce heat-resistant spores. The spoIVB2 mutant enters sporulation, undergoes asymmetric division, and completes engulfment of the forespore by the mother cell but fails to synthesize the spore cortex. We show that SpoIIP, a PG hydrolase and part of the engulfasome, the machinery essential for engulfment, is cleaved by SpoIVB2 into an inactive form. Within the engulfasome, the SpoIIP amidase activity generates the substrates for the SpoIID lytic transglycosylase. Thus, following engulfment completion, the cleavage and inactivation of SpoIIP by SpoIVB2 curtails the engulfasome hydrolytic activity, at a time when synthesis of the spore cortex peptidoglycan begins. SpoIVB2 is also required for normal late gene expression in the forespore by a currently unknown mechanism. Together, these observations suggest a role for SpoIVB2 in coordinating late morphological and gene expression events between the forespore and the mother cell.
Author(s): Martins D, Nerber HN, Roughton CG, Fasquelle A, Barwinska-Sendra A, Vollmer D, Gray J, Vollmer W, Sorg JA, Salgado PS, Henriques AO, Serrano M
Publication type: Article
Publication status: Published
Journal: Molecular Microbiology
Year: 2024
Pages: epub ahead of print
Online publication date: 22/06/2024
Acceptance date: 08/06/2024
Date deposited: 04/07/2024
ISSN (print): 0950-382X
ISSN (electronic): 1365-2958
Publisher: John Wiley and Sons Inc
URL: https://doi.org/10.1111/mmi.15291
DOI: 10.1111/mmi.15291
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