TY - JOUR T1 - FlgM is secreted by the flagellar export apparatus in Bacillus subtilis. AU - Calvo,Rebecca A, AU - Kearns,Daniel B, Y1 - 2014/10/13/ PY - 2014/10/15/entrez PY - 2014/10/15/pubmed PY - 2015/5/12/medline SP - 81 EP - 91 JF - Journal of bacteriology JO - J Bacteriol VL - 197 IS - 1 N2 - The bacterial flagellum is assembled from over 20 structural components, and flagellar gene regulation is morphogenetically coupled to the assembly state by control of the anti-sigma factor FlgM. In the Gram-negative bacterium Salmonella enterica, FlgM inhibits late-class flagellar gene expression until the hook-basal body structural intermediate is completed and FlgM is inhibited by secretion from the cytoplasm. Here we demonstrate that FlgM is also secreted in the Gram-positive bacterium Bacillus subtilis and is degraded extracellularly by the proteases Epr and WprA. We further demonstrate that, like in S. enterica, the structural genes required for the flagellar hook-basal body are required for robust activation of σ(D)-dependent gene expression and efficient secretion of FlgM. Finally, we determine that FlgM secretion is strongly enhanced by, but does not strictly require, hook-basal body completion and instead demands a minimal subset of flagellar proteins that includes the FliF/FliG basal body proteins, the flagellar type III export apparatus components FliO, FliP, FliQ, FliR, FlhA, and FlhB, and the substrate specificity switch regulator FliK. SN - 1098-5530 UR - https://www.unboundmedicine.com/medline/citation/25313396/FlgM_is_secreted_by_the_flagellar_export_apparatus_in_Bacillus_subtilis_ DB - PRIME DP - Unbound Medicine ER -