EXP2 is a nutrient-permeable channel in the vacuolar membrane of Plasmodium and is essential for protein export via PTEX.

Intraerythrocytic malaria parasites reside within a parasitophorous vacuolar membrane (PVM) generated during host cell invasion¹. Erythrocyte remodelling and parasite metabolism require the export of effector proteins and transport of small molecules across this barrier between the parasite surface and host cell cytosol^2,3. Protein export across the PVM is accomplished by the Plasmodium translocon of exported proteins (PTEX) consisting of three core proteins, the AAA+ ATPase HSP101 and two additional proteins known as PTEX150 and EXP2⁴. Inactivation of HSP101 and PTEX150 arrests protein export across the PVM^5,6, but the contribution of EXP2 to parasite biology is not well understood⁷. A nutrient permeable channel in the PVM has also been characterized electrophysiologically, but its molecular identity is unknown^8,9. Here, using regulated gene expression, mutagenesis and cell-attached patch-clamp measurements, we show that EXP2, the putative membrane-spanning channel of PTEX^4,10-14, serves dual roles as a protein-conducting channel in the context of PTEX and as a channel able to facilitate nutrient passage across the PVM independent of HSP101. Our data suggest a dual functionality for a channel operating in its endogenous context.

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