Live-Cell FRET Reveals that Malaria Nutrient Channel Proteins CLAG3 and RhopH2 Remain Associated throughout Their Tortuous Trafficking
Moaz Ahmad, Javier Manzella‐Lapeira, Gagandeep Singh Saggu, Daisuke Ito, Joseph Brzostowski, Sanjay A. Desai
Abstract
Malaria parasites grow within circulating red blood cells and uptake nutrients through a pore on their host membrane. Here, we used gene editing to tag CLAG3 and RhopH2, two proteins linked to the nutrient pore, with fluorescent markers and tracked these proteins in living infected cells. After their synthesis in mature parasites, imaging showed that both proteins are packaged into membrane-bound rhoptries. When parasites ruptured their host cells and invaded new red blood cells, these proteins were detected within a vacuole around the parasite before they migrated and inserted in the surface membrane of the host cell. Using simultaneous labeling of CLAG3 and RhopH2, we determined that these proteins interact tightly during migration and after surface membrane insertion. Red blood cells infected with two parasites had twice the protein at their surface and a parallel increase in the number of nutrient pores. Our work suggests that these proteins directly facilitate parasite nutrient uptake from human plasma.