Both genes are expressed from the RD1 region of the bacterial genome and play a key role in the virulence of the infection.

Mycobacterium tuberculosis uses this ESX-1 secretion system to deliver virulence factors into host macrophage and monocyte white blood cells during infection.

The ESAT-6/CFP-10 heterodimer complex is targeted for secretion by a C-terminal signal sequence on CFP-10 that is recognized by the cytosolic Rv3871 protein.

Rv3871 then interacts with the CFP-10 C-terminal, and escorts the ESAT-6/CFP-10 complex to Rv3870 and Rv3877, a multi-transmembrane protein which makes up the pore that spans the cytosolic membrane of the virulent host cell.

The ESAT-6/CFP-10 complex’s secretion and attachment to the virulent host cell shows its contribution to the pathogenicity of Mycobacterium tuberculosis.