For 10 points, name this protein that marks cytosolic proteins for proteolytic degradation in proteasomes and derives it name from the Latin term for "everywhere."
Addition of this protein to histone 2B is indicative of transcriptionally active DNA, and this polypeptide modifies the lysine residues of target proteins. Viral proteins are (*) tagged with a poly chain of this protein prior to their breakdown and incorporation into major histocompatibility complex molecules. For 10 points, name this protein that marks cytosolic proteins for proteolytic degradation in proteasomes and derives it name from the Latin term for "everywhere."
Addition of this protein to histone 2B is indicative of transcriptionally active DNA, and this polypeptide modifies the lysine residues of target proteins.
ubiquitin