Required for YukE secretion. Probable component or regulator of the ESX/ESAT-6-like secretion system (BsEss). Cells lacking this gene are blocked in YukE secretion (PubMed:23861817, PubMed:24798022). They display an increased bacteriophage SPP1 resistance phenotype (PubMed:15576783). Belongs to the EssC family. Truncated N-terminus.