Protein homeostasis is dependent on the coordinated synthesis, folding, localization and degradation of the thousands of proteins in a living cell. This course deals with selected aspects of the process with emphasis on: i) protein folding and the role of chaperones, ii) protein degradation via the ubiquitin proteasome system, iii) protein folding and quality control in the ER and iv) ER-associated degradation and the unfolded protein response. The course will serve as a foundation for those with an interest in how cellular protein levels and conformations are maintained.