Estudio de proteínas con dominio TIR humanas y bacterianas, mediante su expresión heteróloga en Saccharomyces cerevisiae

Résumé

Living organisms use efficient systems to detect pathogens, such as the Toll-like receptor (TLR) signaling. Upon recognition of a ligand, TLRs amplify the signal via the formation of Supramolecular Organizing Centers (SMOCs) (Kagan et al., 2014), triggering innate immunity responses. These SMOCs are complexes of proteins sharing protein-protein interaction motifs, namely the Toll/interleukin-1 receptor (TIR) domain. Human TLR4 signals from two SMOCs: myddosome and triffosome (Fitzgerald and Kagan, 2020), containing TIRAP and MyD88 or TRAM and TRIF respectively. TIR proteins are widespread along phylogeny and some of their functions remain obscure. Indeed they are not just sticky domains, but some can enzymatically consume NAD+ (Essuman et al., 2018). They play immunity-related roles in animals and plants, and some pathogenic bacteria produce TIR effectors to subvert host immunity (Spear et al., 2009). Among them, Brucella, an intracellular pathogen, bears two TIR effectors called BtpA and BtpB, both secreted by its Type IV Secretion System. BtpA can degrade NAD+ (Essuman et al., 2018), and together with BtpB, they block mammalian TLR signaling (Salcedo et al., 2013) and stabilize host microtubules (Felix et al., 2014). Saccharomyces cerevisiae is an excellent eukaryotic cell model, having highly conserved mechanisms and a myriad of molecular biology tools available (Khurana and Lindquist, 2010). To date, several yeast models of human disease, e.g. the PIK3/PTEN/Akt1(Coronas-Serna et al., 2020b), or bacterial virulence, e.g. the Samonella effector SopB (Rodríguez-Escudero et al., 2006) have been developed by our research group...