The adhesion plaque mediates fluid discharge and duplication of the contractile vacuole complex in Trypanosoma cruzi.

Abstract

This work explores the intricate process of osmoregulation in Trypanosoma cruzi, the causative agent of Chagas disease, with a specific focus on the mechanisms of fluid discharge by the Contractile Vacuole Complex (CVC) and the role of the adhesion plaque (AP), a structure whose densities are located in the membrane domain shared by the CVC and the flagellar pocket. Cryopreparation of T. cruzi samples, combined with volume electron microscopy techniques, allowed for a comprehensive analysis of the essential mechanisms underlying the structural changes that take place in the AP during osmotic stress. Remodeling of the AP coupled to membrane fusion events leads to the formation of pores that connect the flagellar pocket and the CVC. The fluid discharge process followed sequential steps of pore opening, expansion, and closure, to allow membrane fusion. Additionally, this study uncovers structural variations in the CVC during cellular replication, providing insights into the cellular biology and physiology of trypanosomatids.