Analyzing Macromolecular Complexes in Situ Using Cellular Cryo‐Electron Microscopy

Abstract

Cryo‐electron tomography (cryo‐ET) is a powerful technique for imaging biological structures in their native state and in an unperturbed cellular environment. We integrate high resolution imaging by either cryo‐ET and sub‐tomogram averaging or TYGRESS (Tomography‐Guided 3D Reconstruction of Subcellular Structures), with comparative genetics, biochemical methods and EM‐visible labeling to deconstruct the in situ 3D structure and functional organization of macromolecular complexes. We use cilia and flagella as model systems to advance techniques and approaches for high‐resolution imaging of complex cellular structures. Cilia and flagella are ubiquitous organelles with important biological roles in motility and sensation; defects in their assembly or function cause severe human diseases. The normal beating of cilia requires the precise coordination of thousands of dynein motors, but much remains to be learned about dynein's motility and regulation. We are in the process of generating a molecular blueprint of major ciliary complexes to gain a better understanding of the inner workings of these intriguing nano‐machines.