Open AccessCryo-ET of Toxoplasma parasites gives subnanometer insight into tubulin-based structures
Author(s) -
Stella Sun,
Li-av Segev-Zarko,
Muyuan Chen,
Grigore Pintilie,
Michael F. Schmid,
Steven J. Ludtke,
John C. Boothroyd,
Wah Chiu
Publication year - 2022
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2111661119
Subject(s) - conoid , tubulin , microtubule , biology , cytoskeleton , apicomplexa , obligate , intracellular parasite , gliding motility , microbiology and biotechnology , toxoplasma gondii , intracellular , parasite hosting , phylum , cryo electron tomography , flagellum , motility , plasmodium falciparum , biochemistry , anatomy , genetics , bacteria , cell , physics , immunology , malaria , tomography , ecology , world wide web , computer science , antibody , optics
Significance Tubulin polymers are essential for a variety of cellular functions. Using cryo-ET, we reveal the 3D organization of the apical complex inToxoplasma gondii , an intracellular eukaryote with tubulin-based structures, including an apical “conoid” involved in host cell invasion. Our development of an advanced subtomogram averaging protocol for filamentous structures enabled us to accurately assign tubulins in cellular context. At the subnanometer resolution achieved, tubulins were confirmed to assemble into two major forms: canonical subpellicular microtubules (SPMTs) and noncanonical conoid fibrils (CFs). The data further revealed associated proteins in both structures, a dominant orientation of SPMTs, and a unique patterning of the CFs. This work demonstrates an approach that can be used to determine cellular filamentous structures at multiscale resolutions.