@article {18712,
	title = {Rpn1 and Rpn2 coordinate ubiquitin processing factors at the proteasome},
	journal = {Journal of Biological ChemistryJ. Biol. Chem.},
	year = {2012},
	month = {2012/02/08/},
	abstract = {Substrates tagged with (poly)ubiquitin for degradation can be targeted directly to the 26S proteasome where they are proteolysed. Independently, ubiquitin-conjugates may also be delivered by bivalent shuttles. The majority of shuttles attach to the proteasome through a ubiquitin-like domain (UBL) while anchoring cargo at a C-terminal polyubiquitin-binding domain(s). We found that two shuttles of this class, Rad23 and Dsk2, dock at two different receptors embedded within a single subunit of the 19S proteasome regulatory particle (RP), Rpn1. Their association/dissociation constants and affinities for Rpn1 are similar. In contrast, another UBL-containing protein, the deubiquitinase Ubp6, is also anchored by Rpn1, yet dissociates slower, thus behaving as a sometimes proteasome subunit distinct from transiently-associated shuttles. Two neighboring subunits, Rpn10 and Rpn13, show a marked preference for polyubiquitin over UBLs. Rpn10 attaches to the central solenoid portion of Rpn1 although this association is stabilized by the presence of a third subunit, Rpn2. Rpn13 binds directly to the C-terminal portion of Rpn2. These intrinsic polyubiquitin receptors may compete with substrate shuttles for their polyubiquitin-conjugates, thereby aiding release of the emptied shuttles. By binding multiple ubiquitin-processing factors simultaneously, Rpn1 is uniquely suited to coordinate substrate recruitment, deubiquitination, and movement towards the catalytic core. The broad range of affinities for ubiquitin, ubiquitin-like, and non-ubiquitin signals by adjacent yet non-overlapping sites all within the Base illustrates a hub of activity that coordinates the intricate relay of substrates within the proteasome, and consequently influences substrate residency time and commitment to degradation.},
	keywords = {deubiquitination, Proteasome, solenoid, Surface plasmon resonance (SPR), ubiquitin, Ubiquitin-dependent protease},
	isbn = {0021-9258, 1083-351X},
	doi = {10.1074/jbc.M111.316323},
	url = {http://www.jbc.org/content/early/2012/02/08/jbc.M111.316323},
	author = {Rosenzweig,Rina and Bronner,Vered and Zhang,Daoning and Fushman, David and Glickman,Michael H.}
}
