In vivo assembly of the proteasomal complexes, implications for antigen processing

Young Yang, Klaus Früh, Kwangseog Ahn, Per A. Peterson

Research output: Contribution to journalArticlepeer-review

180 Scopus citations


The multicatalytic and multisubunit proteasomal complexes have been implicated in the processing of antigens to peptides presented by class I major histocompatibility complex molecules. Two structural complexes of this proteinase, 20 S and 26 S proteasomes, have been isolated from cells. By analyzing in vivo assembly of the proteasomal complexes we show that the 20 S proteasomal complexes are irreversibly assembled via 15 S assembly intermediates containing unprocessed β-type subunits. The 20 S proteasomes further associate reversibly with proteasome activators PA28 or pre-existing ATPase complexes to form 26 S proteasomal complexes. Our findings that not all of the 20 S proteasomal complexes are assembled into 26 S proteasomal complexes within cells and that all of PA28 and ATPase complexes are associated with 20 S proteasomes strongly suggest that all proteasomal complexes coexist within cells. We further demonstrate that 26 S proteasomal complexes are predominantly present in the cytoplasm and a significant portion of the 20 S proteasomal complexes is associated with the endoplasmic reticulum membrane. Taken together, our findings suggest that depending upon their associated regulatory components, 26 S and 20 S-PA28 proteasomal complexes serve different housekeeping functions within the cells, while they degrade antigens in a cooperative manner in antigen processing.

Original languageEnglish (US)
Pages (from-to)27687-27694
Number of pages8
JournalJournal of Biological Chemistry
Issue number46
StatePublished - Nov 17 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'In vivo assembly of the proteasomal complexes, implications for antigen processing'. Together they form a unique fingerprint.

Cite this