Mycobacterium tuberculosis Toxin CpnT Is an ESX-5 Substrate and Requires Three Type VII Secretion Systems for Intracellular Secretion.

ABSTRACT: CpnT, a NAD⁺ glycohydrolase, is the only known toxin that is secreted by Mycobacterium tuberculosis CpnT is composed of two domains; the C-terminal domain is the toxin, whereas the N-terminal domain is required for secretion. CpnT shows characteristics of type VII secretion (T7S) substrates, including a predicted helix-turn-helix domain followed by a secretion motif (YxxxE). Disruption of this motif indeed abolished CpnT secretion. By analyzing different mutants, we established that CpnT is specifically secreted by the ESX-5 system in Mycobacterium marinum under axenic conditions and during macrophage infection. Surprisingly, intracellular secretion of CpnT was also dependent on both ESX-1 and ESX-4. These secretion defects could be partially rescued by coinfection

SUBMITTER: Izquierdo Lafuente B 

PROVIDER: S-EPMC8092274 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature