<p>This entry describes the SpoIIAB anti-sigma F factor. Sigma F regulates spore development in B subtilis. SpoIIAB binds to sigma F, preventing formation of the transcription complex at the promoter [<cite idref="PUB00013753"/>]. SpoIIAA (anti-anti-sigma F factor) binds to SpoIIAB to inhibit association with sigma F, however SpoIIAB can phosphorylate SpoIIAA, causing disassociation of the SpoIIAA/B complex [<cite idref="PUB00013778"/>]. The SpoIIE phosphatase dephosphorylates SpoIIAA.</p>