Towards a mechanistic understanding of cellular processes by cryoEM

A series of recent hardware and software developments have transformed cryo-electron microscopy (cryoEM) from a niche tool into a method that has become indispensable in structural and functional biology. Samples that are rapidly frozen are encased in a near-native state inside a layer of amorphous ice, and then imaged in an electron microscope cooled to cryogenic temperatures. Despite being conceptually simple, cryoEM owns its success to a plethora of technological developments from numerous research groups. Here, we review the key technologies that have made this astonishing transformation possible and highlight recent trends with a focus on cryo-electron tomography. Additionally, we discuss how correlated microscopy is an exciting and perpendicular development route forward in this already rapidly growing field. We specifically discuss microscopy techniques that allow to complement time-dependent information of dynamic processes to the unique high resolution obtained in cryoEM.