Endophilin-A2 dependent tubular endocytosis promotes plasma membrane repair and parasite invasion

Abstract

Endocytosis of caveolae was previously implicated in the repair of plasma membrane wounds. Here we show that caveolin-1-deficient fibroblasts lacking caveolae upregulate a tubular endocytic pathway, and have a reduced capacity to reseal after permeabilization with pore-forming toxins when compared to wild type cells. Silencing endophilin-A2 expression inhibited fission of endocytic tubules and further reduced plasma membrane repair in cells lacking caveolin-1, supporting a role for tubular endocytosis as an alternative pathway for the removal of membrane lesions. Endophilin-A2 was visualized in association with cholera toxin B-containing endosomes and was recruited to recently formed intracellular vacuoles containing Trypanosoma cruzi, a parasite that utilizes the plasma membrane wounding/repair pathway to invade host cells. Endophilin-A2 deficiency inhibited T. cruzi invasion, and fibroblasts deficient in both caveolin-1 and endophilin-A2 did not survive prolonged exposure to the parasites. These findings reveal a novel cross-talk between caveolin-1 and endophilin-A2 in the regulation of clathrin-independent endocytosis and plasma membrane repair, a process that is subverted by T. cruzi parasites for cell invasion.