High impact information on RPN2

• Further, we demonstrate that RPN4 is extremely short-lived (t(1/2) approximately 2 min), that it directly interacts with RPN2, a subunit of the 26S proteasome, and that rpn4Delta cells are perturbed in their cell cycle [1].
• The 26S proteasome is also required; a mutation of SEN3/RPN2 (sen3-1), which encodes an essential regulatory subunit of the 26S proteasome, partially blocks 4-NQO-induced degradation of Rpb1 [2].
• The yeast SEN3 gene encodes a regulatory subunit of the 26S proteasome complex required for ubiquitin-dependent protein degradation in vivo [3].
• Using a genetic selection for mutants with increased expression of Sen1-derived fusion proteins, we identified mutations in a novel gene, designated SEN3 [3].
• SEN3 is essential and encodes a 945-residue protein with sequence similarity to a subunit of an activator of the 20S proteasome from bovine erythrocytes, called PA700 [3].

Biological context of RPN2

• Disruption of the SEN3 did not affect cell viability, but led to temperature-sensitive growth [4].
• The functional abnormality induced by SEN3 disruption differs considerably from various phenotypes shown by the nin1-1 mutation, suggesting that these two regulatory subunits of the 26S proteasome play distinct roles in the various processes mediated by the 26S proteasome [4].
• The bipartite nuclear localization sequence of Rpn2 is required for nuclear import of proteasomal base complexes via karyopherin alphabeta and proteasome functions [5].

Associations of RPN2 with chemical compounds

• CDNA cloning of p112, the largest regulatory subunit of the human 26s proteasome, and functional analysis of its yeast homologue, sen3p [4].
• Maintenance of SEN3 disruptant cells at the restrictive temperature resulted in a variety of cellular dysfunctions, including defects in proteolysis mediated by the ubiquitin pathway, in the N-end rule system, in the stress response upon cadmium exposure, and in nuclear protein transportation [4].

Other interactions of RPN2

• The SEN3 also was identified in a synthetic lethal screen with the nin1-1 mutant, a temperature-sensitive mutant of NIN1 [4].
• By cross-linking experiments, Rpn1 and Rpn2 were identified as Ubl-binding subunits [6].

References