Super-resolution of membrane proteins in Trypanosoma cruzi

ESCALANTE, GONZALO; LOPEZ, LUCIA FERNANDA; MUCCI, JUAN; PUIG PARADA, RAQUEL; CAMPETELLA, OSCAR; STEFANI, FERNANDO DANIEL

Congreso; L Reunión Anual SAB; 2022

Trypanosoma cruzi (T. cruzi) is the parasite responsible for Chagas disease, an endemicdisease with a high impact in Latin America. Despite this epidemiological situation,vaccines are not yet available and the available drugs have unclear therapeutic efficacyand adverse side effects. To establish a persistent infection, T. cruzi has developed a self-protection mechanism to stay out of the radar of the immune system. One of the mainevasion strategies involves the capture of sialic acid from the host's bloodstream. For thatpurpose, the parasite has a specific enzyme located in its membrane, trans-sialidase (TS),which is capable of transferring sialic acid (SA) from host glycoproteins to other heavilyglycosylated membrane proteins of T. cruzi called mucins, capable of storing SA. In thiscontext, it is essential to know the organization and spatial distribution of mucins and TSin the parasite’s membrane, which cannot be resolved by conventional fluorescencemicroscopy.In this work, we characterize the distribution of the two mentioned proteins by super-resolution fluorescence microscopy, applying 2D and 3D STORM (Stochastic OpticalReconstruction Microscopy). We worked with parasites in their infective form pretreatedwith SA and immunolabeled. It was possible to visualize domains of TS and mucins with alateral resolution of 20 nm and an axial resolution of 50 nm, approximately. Moreover, wedeveloped a 2D cluster analysis algorithm that is based on the distribution of distancesbetween localizations, to describe protein domains.A preliminary analysis indicates that mucins and TS are found forming heterogeneoussparced protein domains in the parasite membrane. It is also observed that the TSdomains are located at closer distances than a random distribution.