Binds to acyl-CoA. Processed into the SDF-2 (spore differentiation factor 2) a peptide which triggers sporulation. SDF-2 appears to stimulate prestalk cells to release additional SDF-2 by acting through a signal transduction pathway that also involves dhkA, regA and PKA. Induces encapsulation of prespore cells in a dhkA-dependent manner. GABA induces the release of acbA from prespore cells and induces the exposure of tagC on the surface of prestalk cells where it can convert acbA to SDF-2. Glutamate acts as a competitive inhibitor and is also able to inhibit induction of sporulation by SDF-2. Interacts with dhkA. Expressed in vegetative cells but is rapidly turned over during early development before reaccumulating during late development in prespore cells but not in prestalk cells. Expression decreases in early development and reappears in late development. Highly expressed in prespore cells at the slug stage (at protein level). Cells form fruiting bodies with a reduction of 90% of viable spores and without SDF-2 activity. Diazepam (Valium) can mimic SDF-2 in Dictyostelium bioassay. Belongs to the ACBP family.