Members of this family are involved in quorum sensing processes. In gram negative bacteria, N-acylhomoserine lactones (AHLs) act as signals. As the bacterial density increases, AHLs accumulate, and once they reach a critical level (quorum), they interact with cognate receptor proteins, which then affect target gene expression. Some AHLs are synthesized by LuxM (AHL synthase) and homologs (VanM and opaM)[1]. LuxM enzymes use S-adenosyl-methionine (SAM) as one of its two substrates and are capable of using either acyl-acyl-carrier-protein (acyl-ACP) or acyl-coenzyme A (acyl-CoA) as the other substrate [2]. VanM, the LuxM homolog, produces two auto-inducers C6HSL and 3OC6HSL. Both autoinducers are detected by the VanN receptor. The autoinducers HAI-1, is synthesized by the cytoplasmic enzymes LuxM [3].

1: A New N-Acyl Homoserine Lactone Synthase in an Uncultured Symbiont of the Red Sea Sponge Theonella swinhoei. Britstein M, Devescovi G, Handley KM, Malik A, Haber M, Saurav K, Teta R, Costantino V, Burgsdorf I, Gilbert JA, Sher N, Venturi V, Steindler L; Appl Environ Microbiol. 2015;82:1274-1285. PMID:26655754

2: Quorum sensing: how bacteria can coordinate activity and synchronize their response to external signals?. Li Z, Nair SK; Protein Sci. 2012;21:1403-1417. PMID:22825856

3: Bacterial quorum-sensing network architectures. Ng WL, Bassler BL; Annu Rev Genet. 2009;43:197-222. PMID:19686078