This lecture covers the mechanisms of membrane protein quality control at the endoplasmic reticulum (ER), focusing on ER-associated degradation (ERAD). Topics include recognition, retrotranslocation, ubiquitination, and degradation of misfolded proteins. The lecture also discusses ERAD substrates in yeast and mammals, the unique features of Inner Nuclear Membrane (INM) ERAD, and the role of the Asi ubiquitin ligase complex. Additionally, it explores how membrane substrates are selected for ERAD and the involvement of various ERAD components in the degradation process.