National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
S10OD021600
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
P41GM103832
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM079429
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
P01GM121203
米国
National Institutes of Health/National Institute of Mental Health (NIH/NIMH)
R21MH125285-01A1
米国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2022 タイトル: Cryo-ET of parasites gives subnanometer insight into tubulin-based structures. 著者: Stella Y Sun / Li-Av Segev-Zarko / Muyuan Chen / Grigore D Pintilie / Michael F Schmid / Steven J Ludtke / John C Boothroyd / Wah Chiu / 要旨: Tubulin is a conserved protein that polymerizes into different forms of filamentous structures in , an obligate intracellular parasite in the phylum Apicomplexa. Two key tubulin-containing ...Tubulin is a conserved protein that polymerizes into different forms of filamentous structures in , an obligate intracellular parasite in the phylum Apicomplexa. Two key tubulin-containing cytoskeletal components are subpellicular microtubules (SPMTs) and conoid fibrils (CFs). The SPMTs help maintain shape and gliding motility, while the CFs are implicated in invasion. Here, we use cryogenic electron tomography to determine the molecular structures of the SPMTs and CFs in vitrified intact and detergent-extracted parasites. Subvolume densities from detergent-extracted parasites yielded averaged density maps at subnanometer resolutions, and these were related back to their architecture in situ. An intralumenal spiral lines the interior of the 13-protofilament SPMTs, revealing a preferred orientation of these microtubules relative to the parasite's long axis. Each CF is composed of nine tubulin protofilaments that display a comma-shaped cross-section, plus additional associated components. Conoid protrusion, a crucial step in invasion, is associated with an altered pitch of each CF. The use of basic building blocks of protofilaments and different accessory proteins in one organism illustrates the versatility of tubulin to form two distinct types of assemblies, SPMTs and CFs.