This protein is predicted to span the membrane several times. It is only found in genomes of species that perform sporulation, such as Bacillus subtilis, Clostridium tetani, and other members of the Firmicutes (low-GC Gram-positive bacteria). Mutation of this sigmaE-dependent gene blocks development of the spore cortex. The length of the C-terminal region, which includes some hydrophobic regions, is variable.