Immunogold labeling and electron tomography of plant endosomes.

High-resolution imaging of endosomal compartments and associated organelles can be achieved using state-of-the-art electron microscopy techniques, such as the combination of cryofixation/freeze-substitution for sample processing and electron tomography for three-dimensional (3D) analysis. This chapter deals with the main steps associated with these imaging techniques: selection of samples suitable for studying plant endosomes, sample preparation by high-pressure freezing/freeze-substitution, and electron tomography of plastic sections. In addition, immunogold approaches for identification of subcellular localization of endosomal and cargo proteins are also discussed.