Mycobacterium tuberculosis secreted protein ESAT-6 interacts with the human protein syntenin-1

Abstract

Abstract In order to study the function of the Mycobacterium tuberculosis protein ESAT-6 in the infection process, we searched for host proteins that interact with this secreted mycobacterial protein. Using a yeast two-hybrid system we identified the rat syntenin-1 protein as a candidate to interact with ESAT-6. This interaction was confirmed in vitro by protein overlay and by surface plasmon resonance using recombinant ESAT-6 and human syntenin-1, and by co-purification analysis of the mycobacterial expressed ESAT-6 and macrophage derived syntenin-1. The interaction domains were localized by two-hybrid studies using truncated derivatives of both proteins and by peptide spot analysis. Two domains of each protein mediate the ESAT-6/syntenin-1 interaction. The C-terminus of ESAT-6 binds to the PDZ-domains of syntenin-1 and the N-terminus of ESAT-6 binds to the N-terminus of syntenin-1. Thus, the host protein syntenin-1 represents a possible cellular receptor for the mycobacterial protein ESAT-6.