The endoplasmic reticulum takes care of the folding, assembly, and quality control of thousands of proteins destined to the different compartments of the endomembrane system, or to be secreted in the apoplast. Here we describe how these early events in the life of all these proteins can be followed biochemically by using velocity or isopycnic ultracentrifugation, metabolic labeling with radioactive amino acids, and immunoprecipitation in various conditions.
Keywords: Chaperones; Endoplasmic reticulum; Immunoprecipitation; Protein folding; Protein oligomerization; Protein synthesis; Protein–protein interactions; Pulse-chase; Ultracentrifugation.