Descripción del proyecto
Caracterización de sistema de secreción de tipo VII en «Mycobacterium abscessus»
«Mycobacterium abscessus» (Mab) es una micobacteria no tuberculosa multirresistente responsable de infecciones nosocomiales pulmonares y extrapulmonares. Mab sobrevive y prolifera dentro de los macrófagos, de forma parecida a «Mycobacterium tuberculosis» (Mtb). La virulencia de Mtb está mediada por proteínas secretadas en las células hospedadoras por el sistema de secreción de tipo VII (T7SS, por sus siglas en inglés), lo que convierte a este sistema en un candidato para el desarrollo de tratamientos. Los T7SS están codificados por cinco locus genéticos en Mtb, denominados de ESX-1 a ESX-5, y cada sistema desempeña un papel concreto dentro de la célula. Mab solo posee dos T7SS: ESX-3 y un ESX-4 totalmente intacto y funcional, que es fundamental para su supervivencia intracelular. El proyecto ESX-4 T7SS, financiado con fondos europeos, propone un estudio funcional y estructural interdisciplinar de los mecanismos de secreción mediados por T7SS.
Objetivo
Mycobacterium abscessus (Mab) is an opportunistic-multidrug-resistant non-tuberculous mycobacteria responsible for multiple clinically-acquired infections both pulmonary and extrapulmonary. Unlike many rapidly growing mycobacteria (RGM), Mab is able to survive and multiply within macrophages, similar to slow growing mycobacteria (SGM) such as M. tuberculosis (Mtb). In Mtb, five T7SS (ESX-1-5) have been identified and shown to be essential for intracellular survival (ESX-1), virulence (ESX-1 and ESX-5) or growth (ESX-3). T7SS are composed of five protein components essential for function: EccB, EccC, EccD, EccE and MycP. Except for a low-resolution structure of the holo ESX-5 complex from the host lab at 13 Å resolution, no structural data on any T7SS have been published to date, rendering structural work timely and eagerly awaited by relevant communities. Deemed inactive due to its lack of one of the established T7SS components EccE4, ESX-4 has been considered an ancestral T7SS form. However, Mab possess a fully intact and functional ESX-4, essential for its intracellular survival, rendering it a highly attractive target for an in-depth characterization. Here, I propose an interdisciplinary project that includes both functional and structural investigation. As the 2 M Dalton-holo-complex crosses the Mab inner membrane, experimental structural work will be challenging and require an integrative modeling approach to combine diverse experimental data sets. Complementary infection biology experiments including microbiology, genetics and cell biology will be carried out by collaborators. With this work, I aim to respond to central questions related to T7SS in general and Mab ESX-4 specifically, such as: what is the mechanism of T7SS-mediated secretion? What makes ESX-4 specific and different from other T7SS? What is the specific role of EccE4 to establish a functionally active ESX4? and What are the substrates and specific mechanism of ESX-4 substrate recognition?
Ámbito científico
Programa(s)
Régimen de financiación
MSCA-IF-EF-ST - Standard EFCoordinador
69117 Heidelberg
Alemania