10-kDa culture filtrate protein (CFP-10) is an
antigen that contributes to the virulence of
Mycobacterium tuberculosis. CFP-10 forms a tight 1:1 heterodimeric complex with 6kDaA early secreted
antigen target (ESAT-6). In the mycobacterial cell, these two proteins are interdependent for their stability. The ESAT-6/CFP-10 complex is secreted by the ESX-1 secretion system, also known as the RD1 region.
Mycobacterium tuberculosis uses this ESX-1 secretion system to deliver virulence factors into host
macrophage and
monocyte white blood cells during infection. In
Mycobacterium tuberculosis, the ESX-1 secretion system, a
type VII bacterial secretion system, includes Rv3877 and two AAA ATPases, Rv3870 and Rv3871, the latter a cytosolic protein, as subunits. 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. Once ESAT-6/CFP-10 is next to the membrane of the host cell, the CFP-10 C-terminal attaches and binds itself to the cell surface. The ESAT-6/CFP-10 complex’s secretion and attachment to the host cell shows its contribution to the pathogenicity of
Mycobacterium tuberculosis. == Structure ==