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Vibrio cholerae MARTX toxin multifunctionality silences inflammatory response to toxin mediated cytoskeletal collapse

Woida, PJ;Satchell, KJF;

Multifunctional autoprocessing repeats-in-toxin (MARTX) toxins are pore-forming toxins that translocate multiple functionally independent effector domains into a target eukaryotic cell. Vibrio cholerae colonizes intestinal epithelial cells (IECs) and utilizes a MARTX toxin with three effector domains — the actin cross-linking domain (ACD), the Rho inactivation domain (RID), and the alpha/beta hydrolase domain (ABH) — to regulate innate immunity and enhance colonization. Whether these multiple catalytic enzymes delivered from a single toxin have coordinated function has not been explored. Using cultured IECs, we demonstrate ACD-induced cytoskeletal collapse activates a robust proinflammatory response that is blocked by the action of co-delivered RID and ABH. Thus, MARTX toxins utilize multiple enzymatic activities on a single toxin to silence the host response to both bacterial factors and effector function. Further, these data explain that V. cholerae utilizes the MARTX toxin to suppress intestinal inflammation and contribute to cholera being classically defined as non-inflammatory diarrheal disease.