RelE and RelB form a toxin-antitoxin system. RelE represses translation, probably through binding ribosomes ([1], [2]). RelB stably binds RelE, presumably deactivating it.

1: Purification of the RelB and RelE proteins of Escherichia coli: RelE binds to RelB and to ribosomes. Galvani C, Terry J, Ishiguro EE; J Bacteriol 2001;183:2700-2703. PMID:11274135

2: Rapid induction and reversal of a bacteriostatic condition by controlled expression of toxins and antitoxins. Pedersen K, Christensen SK, Gerdes K; Mol Microbiol 2002;45:501-510. PMID:12123459