Localization of the proteasomal ubiquitin receptors Rpn10 and Rpn13 by electron cryomicroscopy.
Two canonical subunits of the 26S proteasome, Rpn10 and Rpn13, function as ubiquitin (Ub) receptors. The mutual arrangement of these subunits--and all other non-ATPase subunits--in the regulatory particle is unknown. Using electron cryomicroscopy, we calculated difference maps between wild-type 26S proteasome from Saccharomyces cerevisiae and deletion mutants (rpn10Δ, rpn13Δ, and rpn10Δrpn13Δ). These maps allowed us to localize the two Ub receptors unambiguously. Rpn10 and Rpn13 mapped to the apical part of the 26S proteasome, above the N-terminal coiled coils of the AAA-ATPase heterodimers Rpt4/Rpt5 and Rpt1/Rpt2, respectively. On the basis of the mutual positions of Rpn10 and Rpn13, we propose a model for polyubiquitin binding to the 26S proteasome.
Department of Molecular Structural Biology, Max-Planck-Institute of Biochemistry, Martinsried 82152, Germany.
Eri
E
Sakata
Stefan
S
Bohn
Oana
O
Mihalache
Petra
P
Kiss
Florian
F
Beck
Istvan
I
Nagy
Stephan
S
Nickell
Keiji
K
Tanaka
Yasushi
Y
Saeki
Friedrich
F
Förster
Wolfgang
W
Baumeister
D000818:Animals; D020285:Cryoelectron Microscopy / Q000379:methods*; D004331:Drosophila melanogaster; D013058:Mass Spectrometry; D008958:Models, Molecular; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
C122019:RPN10 protein, S cerevisiae; C529711:RPN13 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D046988:Proteasome Endopeptidase Complex