National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM083122
米国
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
AI150715
米国
Cancer Prevention and Research Institute of Texas (CPRIT)
RP140082
米国
National Science Foundation (NSF, United States)
MCB1553334
米国
Welch Foundation
I-2075-20210327
米国
引用
ジャーナル: Nat Commun / 年: 2023 タイトル: Cryo-tomography reveals rigid-body motion and organization of apicomplexan invasion machinery. 著者: Long Gui / William J O'Shaughnessy / Kai Cai / Evan Reetz / Michael L Reese / Daniela Nicastro / 要旨: The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and toxoplasmosis. Its structure and ...The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and toxoplasmosis. Its structure and mechanism of motion are poorly understood. We used cryo-FIB-milling and cryo-electron tomography to visualize the 3D-structure of the apical complex in its protruded and retracted states. Averages of conoid-fibers revealed their polarity and unusual nine-protofilament arrangement with associated proteins connecting and likely stabilizing the fibers. Neither the structure of the conoid-fibers nor the architecture of the spiral-shaped conoid complex change during protrusion or retraction. Thus, the conoid moves as a rigid body, and is not spring-like and compressible, as previously suggested. Instead, the apical-polar-rings (APR), previously considered rigid, dilate during conoid protrusion. We identified actin-like filaments connecting the conoid and APR during protrusion, suggesting a role during conoid movements. Furthermore, our data capture the parasites in the act of secretion during conoid protrusion.