This family of small proteins is found in the membrane and is necessary for kinase KinB signalling during sporulation. There is a conserved GFF sequence motif. The initiation of sporulation in Bacillus subtilis is dependent on the phosphorylation of the Spo0A transcription factor mediated by the phospho-relay and by two major kinases, KinA and KinB.

1: Identification of a membrane protein involved in activation of the KinB pathway to sporulation in Bacillus subtilis. Dartois V, Djavakhishvili T, Hoch JA; J Bacteriol. 1996;178:1178-1186. PMID:8576055