This family of proteins is regulated by the ferric uptake regulator protein Fur [1]. This family does not regulate the lutABC operon encoding iron sulfur-containing enzymes necessary for growth on lactate [2].

1: The Bacillus subtilis iron-sparing response is mediated by a Fur-regulated small RNA and three small, basic proteins. Gaballa A, Antelmann H, Aguilar C, Khakh SK, Song KB, Smaldone GT, Helmann JD; Proc Natl Acad Sci U S A. 2008;105:11927-11932. PMID:18697947

2: The FsrA sRNA and FbpB protein mediate the iron-dependent induction of the Bacillus subtilis lutABC iron-sulfur-containing oxidases. Smaldone GT, Antelmann H, Gaballa A, Helmann JD; J Bacteriol. 2012;194:2586-2593. PMID:22427629