May be involved in the ESX-1 / type VII specialized secretion system (T7SS), which exports several proteins including EsxA and EsxB (Probable). Involved in DNA conjugation in the recipient strain (PubMed:18554329). Loss of DNA conjugation when disrupted in recipient strain; strain still secretes EsxB (PubMed:18554329). In the well characterized mc(2)155 strain this gene not present. DNA conjugation in M.smegmatis is unidirectional with distinct donor and recipient strains; mc(2)155 is a donor strain while MKD8 is a recipient strain. Mutations in a donor strain that alter DNA transfer do not always alter DNA transfer in a recipient strain. Truncated N-terminus.