Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Science Foundation (NSF, United States)
The movement and pathogenicity of trypanosomatid species, the causative agents of trypanosomiasis and leishmaniasis, are dependent on a flagellum that contains an axoneme of dynein-bound doublet microtubules (DMTs). In this work, we present cryo-electron microscopy structures of DMTs from two trypanosomatid species, Leishmania tarentolae and Crithidia fasciculata , at resolutions up to 2.7 angstrom. The structures revealed 27 trypanosomatid-specific microtubule inner proteins, a specialized dynein-docking complex, and the presence of paralogous proteins that enable higher-order periodicities or proximal-distal patterning. Leveraging the genetic tractability of trypanosomatid species, we quantified the location and contribution of each structure-identified protein to swimming behavior. Our study shows that proper B-tubule closure is critical for flagellar motility, exemplifying how integrating structural identification with systematic gene deletion can dissect individual protein contributions to flagellar motility.
Organizational Affiliation:
Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
Molecular Cell Biology (MCB) graduate program, Division of Biology and Biomedical Sciences, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
Department of Cell Biology and Physiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
Institute of Cell Biology, University of Bern, Bern, Switzerland.
Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories, Edinburgh, UK.
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