CbeA_antitoxin is a family of cognate antitoxins to the CbtA toxins that act by inhibiting the polymerisation of cytoskeletal proteins, see Pfam:PF06755. These are classified as a type IV toxin-antitoxin system [1]. The family includes three proteins from E. coli YagB, YeeU and YfjZ, which act not by forming a complex with CbtA but through acting as antagonists to the CbtA toxicity, by stabilising the CbtA target proteins. For example, YeeU binds directly to both MreB and FtsZ and enhances the bundling of their filaments in vitro. YeeU is also able to neutralise the toxicity caused by other MreB and FtsZ inhibitors, such as A22 [S-(3, 4-dichlorobenzyl)isothiourea] for MreB, and SulA and DicB for FtsZ [2]. Thus CbeA, for cytoskeleton bundling-enhancing factor A, is proposed as a general name for all of these antitoxin proteins.

1: A novel family of Escherichia coli toxin-antitoxin gene pairs. Brown JM, Shaw KJ; J Bacteriol. 2003;185:6600-6608. PMID:14594833

2: YeeU enhances the bundling of cytoskeletal polymers of MreB and FtsZ, antagonizing the CbtA (YeeV) toxicity in Escherichia coli. Masuda H, Tan Q, Awano N, Wu KP, Inouye M; Mol Microbiol. 2012;84:979-989. PMID:22515815