CHAPTER 181 – The Ubiquitin-Proteasome System

摘要: Protein ubiquitination is now recognized to be almost as pervasive protein phosphorylation, and it would impossible enumerate here all the known instances in which an important component of a cellular regulatory mechanism. Instead, few illustrative examples will briefly described. Perhaps most widely appreciated function ubiquitin-dependent proteolysis cell cycle control. Multiple, irreversible transitions cycle, including G1-to-S, metaphase-to-anaphase, mitotic exit, require timed degradation specific positive or negative cell-cycle regulators. The ubiquitin-proteasome system provides major route for short-lived intracellular proteins eukaryotes. Ubiquitin extraordinarily well-conserved 76-residue polypeptide that found either free covalently joined through its C-terminus variety cytoplasmic, nuclear, membrane proteins. Although best defined ubiquitin direct substrate their destruction by 26S proteasome, this not only role. In recent years, has also been shown regulate endocytosis trafficking proteins, modify signal transduction pathways, alter activity ribosome. purpose chapter give general description system, while highlighting some key pathways depend on it.