TY - JOUR
T1 - The proteasome subunit, C2, contains an important site for binding of the PA28 (11S) activator
AU - Kania, Mary A.
AU - Demartino, George N.
AU - Baumeister, Wolfgang
AU - Goldberg, Alfred L.
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1996
Y1 - 1996
N2 - The PA28, or 11S regulatory complex, stimulates the peptidase activities of the 20S proteasome. Monoclonal antibodies were screened for their ability to inhibit the activation by PA28 of proteasomes from rabbit reticulocytes. We identified one antibody that inhibited proteasome activation by PA28 and dissociated formed proteasome-PA28 complexes. A fourfold molar excess of antibody to proteasome markedly reduced the PA28 activation of three peptidase activities. Examination of proteasome-antibody mixtures by electron microscopy revealed that the antibody formed chains of proteasomes, and digital image analysis of individual proteasomes demonstrated that the antibody binds to the outer α rings. This antibody recognizes proteasome subunit C2, which we conclude contains an important contact site for the PA28 activator. However, the antibody did not block proteasome activation by PA700, or 19S regulator, which also associates with the α rings. Thus, these two regulators appear to bind to the proteasome at different sites.
AB - The PA28, or 11S regulatory complex, stimulates the peptidase activities of the 20S proteasome. Monoclonal antibodies were screened for their ability to inhibit the activation by PA28 of proteasomes from rabbit reticulocytes. We identified one antibody that inhibited proteasome activation by PA28 and dissociated formed proteasome-PA28 complexes. A fourfold molar excess of antibody to proteasome markedly reduced the PA28 activation of three peptidase activities. Examination of proteasome-antibody mixtures by electron microscopy revealed that the antibody formed chains of proteasomes, and digital image analysis of individual proteasomes demonstrated that the antibody binds to the outer α rings. This antibody recognizes proteasome subunit C2, which we conclude contains an important contact site for the PA28 activator. However, the antibody did not block proteasome activation by PA700, or 19S regulator, which also associates with the α rings. Thus, these two regulators appear to bind to the proteasome at different sites.
KW - PA28
KW - antibody
KW - proteasome
KW - proteasome activation
UR - http://www.scopus.com/inward/record.url?scp=0029874055&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029874055&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1996.00510.x
DO - 10.1111/j.1432-1033.1996.00510.x
M3 - Article
C2 - 8612623
AN - SCOPUS:0029874055
SN - 0014-2956
VL - 236
SP - 510
EP - 516
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -