Identification of the Cdc48•20 S Proteasome as an Ancient AAA+ Proteolytic Machine

Take Another Cap Selective cytosolic protein degradation is mediated primarily by the proteasome, which is comprised of a core peptidase and a regulatory cap. Current dogma holds that the 20 S core peptidase of the proteasome functions exclusively with the 19 S regulatory particle in eukaryotes, with PAN in archaea, and with Mpa in mycobacteria. Barthelme and Sauer (p. 843 , published online 26 July 2012; see the Perspective by Matouschek and Finley ) now suggest that another type of proteasome can assemble in archaea consisting of the double-ring AAA+ protein, Cdc48, in complex with the 20 S core protease.