Reconstitution of hybrid proteasomes from purified PA700–20 S complexes and PA28αβ activator: ultrastructure and peptidase activities

The activity of the proteasome, the major non-lysosomal proteinase in eukaryotes, is stimulated by two activator complexes, PA700 and PA28. PA700–20 S-PA700 proteasome complexes, generally designated as 26 S proteasomes, degrade proteins, whereas complexes of the type PA28–20 S-PA28 degrade only pep...

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Bibliographic Details
Published in:Journal of molecular biology 2001-10, Vol.313 (3), p.465-471
Main Authors: Kopp, Friedrich, Dahlmann, Burkhardt, Kuehn, Lothar
Format: Article
Language:English
Subjects:
activator
electron microscopy
human
hybrid
proteasome
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Summary:The activity of the proteasome, the major non-lysosomal proteinase in eukaryotes, is stimulated by two activator complexes, PA700 and PA28. PA700–20 S-PA700 proteasome complexes, generally designated as 26 S proteasomes, degrade proteins, whereas complexes of the type PA28–20 S-PA28 degrade only peptides. We report, for the first time, the in vitro reconstitution of previously identified hybrid proteasomes (PA700–20 S-PA28) from purified PA700–20 S proteasome complexes and PA28 activator. In electron micrographs, the hybrid appears as a corkscrew-shaped particle with a PA700 and a PA28 activator each bound to a terminal α-disk of the 20 S core proteasome. The multiple peptidase activities of hybrid proteasomes are not different from those of PA28–20 S-PA28 or PA700–20 S-PA700 complexes.
ISSN:0022-2836
1089-8638
DOI:10.1006/jmbi.2001.5063