Cryoelectron tomography of eukaryotic cells.

Biological processes involve a high degree of protein dynamics resulting in a constant remodeling of the cellular landscape at the molecular level. Orchestrated changes lead to significant rearrangement of the eukaryotic cytoskeleton and nuclear structures. Visualization of the cellular landscape in the unperturbed state is essential for understanding these processes. The development of cryoelectron tomography (cryo-ET) and its application to eukaryotic cells has provided a major step forward toward better realizing these processes. In conjunction with rapid freezing techniques, that is, vitrification by plunge-freezing and high-pressure freezing, cryo-ET is most suitable for investigating cellular ultrastructures in a close-to-life state. Here, we review the application of cryo-ET to the study of eukaryotic cells, with special emphasis on sample preparation, cytoskeleton organization, and macromolecular structures observed at a resolution of 4-6 nm.