Transferrin uptake in Trypanosoma cruzi is impaired by interference on cytostome-associated cytoskeleton elements and stability of membrane cholesterol, but not by obstruction of clathrin-dependent endocytosis.
Transferrin uptake by Trypanosoma cruzi epimastigotes occurs mainly through the cytostome/cytopharynx. Here, we present evidences for the association of sterol-rich membrane domains with the transferrin endocytic site. Assays using pharmacological treatments to disrupt clathrin-coated pits and hinder caveolae formation showed no association between transferrin uptake and clathrin-dependent endocytosis, but indicated that cholesterol stability in membrane domains is essential for the endocytosis of transferrin. Furthermore, it was observed a connection between the integrity of cytoskeleton elements at the cytopharynx and the function of the cytostome. Our data show that T. cruzi epimastigotes depend on a specialized pathway for transferrin uptake, which is cholesterol-dependent, clathrin-independent, and closely associated with the structural stability of the cytostome/cytopharynx cytoskeleton.
Corrêa
José R
JR
Laboratório de Ultra-estrutura Celular, Instituto Oswaldo Cruz/FIOCRUZ, 21045-900 Rio de Janeiro, RJ, Brazil.
Atella
Georgia C
GC
Batista
Marcelo M
MM
Soares
Maurilio J
MJ
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism*; D002966:Clathrin / Q000502:physiology*; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D005372:Filipin / Q000494:pharmacology; D005434:Flow Cytometry; D046529:Microscopy, Electron, Transmission; D014168:Transferrin / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000378:metabolism* / Q000648:ultrastructure; D047392:beta-Cyclodextrins / Q000494:pharmacology
D000890:Anti-Infective Agents; D002966:Clathrin; D014168:Transferrin; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D003571:Cytochalasin B; D005372:Filipin; D002784:Cholesterol