Required for host-cell death and may support an EsxA-independent virulence function (PubMed:23869560). Secreted processed form of EspB binds to phosphatidic acid and phosphatidylserine (PubMed:23869560). Inhibits IFN-gamma-induced autophagy in murine macrophages (PubMed:25641595). Mature EspB oligomerizes and forms donut-shaped rings. In contrast, the full-length protein does not oligomerize (PubMed:26051906). Interacts with the C-terminal region of EspK (PubMed:17676952). Secreted via the ESX-1 / type VII secretion system (T7SS) (PubMed:17676952). Secretion requires both EspK and EccCb1, but not EspA, EspC and EspD (PubMed:17676952, PubMed:23869560). The N-terminal region contains a fused PE/PPE homology domain. The C-terminal region is disordered. Cleaved in the C-terminal region by MycP1 (PubMed:17676952, PubMed:20227664, PubMed:23620593, PubMed:24113528). The exact location of the cleavage sites has been the subject of conflicting reports (PubMed:20227664, PubMed:23620593). Further in vitro studies confirmed that Ala-358 is the primary cleavage site and Ala-386 is a secondary cleavage site (PubMed:24113528). Likely translocated as a full-length protein into the periplasm, where it is proteolyzed by MycP1 (PubMed:17676952, PubMed:20227664). Proteolysis may serve to limit the secretion of other ESX-1 substrates (PubMed:20227664). BTP15, an inhibitor of ESX-1 secretion, decreases secretion of this protein without being bacteriocidal. BTP15 inhibits autophosphorylation of MprB with subsequent up-regulation of espA and decreased secretion of EspB and EsxA (PubMed:25299337). Belongs to the EspB family.