Opis projektu
Charakterystyka systemu sekrecji typu VII u Mycobacterium abscessus
Mycobacterium abscessus (Mab) to wielolekooporny, niegruźliczy prątek gruźlicy powodujący kliniczne zakażenia płucne i pozapłucne. Mab, podobnie jak M. tuberculosis (Mtb), żyje i namnaża się w makrofagach. W wirulencji Mtb pośredniczą białka wydzielane do komórek gospodarza przez system sekrecji typu VII (ang. type VII secretion system, T7SS), co czyni go możliwym kandydatem na potrzeby opracowania terapii. Systemy T7SS są kodowane w pięciu loci genetycznych Mtb, o nazwach od ESX-1 do ESX-5, z których każdy pełni w komórce określoną rolę. W przypadku Mab występują tylko dwa T7SS, ESX-3 oraz całkowicie nieuszkodzony i funkcjonalny ESX-4, które są niezbędne do jego przetrwania wewnątrz komórki. Zespół finansowanego ze środków UE projektu ESX-4 T7SS proponuje interdyscyplinarne badania funkcjonalne i strukturalne mechanizmów sekrecji, w której pośredniczy T7SS.
Cel
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?
Dziedzina nauki
Program(-y)
Temat(-y)
System finansowania
MSCA-IF-EF-ST - Standard EFKoordynator
69117 Heidelberg
Niemcy