ESX-1 exported proteins CFP-10 and EspC have a targeting element at their C-terminus (black ovals) that directs them to interact with cytosolic AAA ATPases EccCb1 and EccA1, respectively. Through interactions with cytoplasmic membrane proteins, these AAA ATPases are proposed to deliver proteins to an ESX-1 export channel. EccD1 is a leading candidate for being a component of this channel. ESAT-6 lacks a C-terminal targeting element and must form a complex with CFP-10 in order to be exported. The functions of EccE1, EccCa1, and EccB1 are unknown, but all are predicted cytoplasmic membrane proteins and core components of the ESX-1 pathway. MycP1 is a membrane protein with protease activity. Other proteins reported to be exported by the ESX-1 system and pictured here are EspA, EspB, and EspR.