Prediction of a common structural scaffold for proteasome lid, COP9-signalosome and eIF3 complexes

Background: The 'lid' subcomplex of the 26S proteasome and the COP9 signalosome (CSN complex) share a common architecture consisting of six subunits harbouring a so-called PCI domain (proteasome, CSN, eIF3) at their C-terminus, plus two subunits containing MPN domains (Mpr1/Pad1 N-terminal). The translation initiation complex eIF3 also contains PCI- and MPNdomain proteins, but seems to deviate from the 6+2 stoichiometry. Initially, the PCI domain was defined as the region of detectable sequence similarity between the components mentioned above. Results: During an exhaustive bioinformatical analysis of proteasome components, we detected multiple instances of tetratrico-peptide repeats (TPR) in the N-terminal region of most PCI proteins, suggesting that their homology is not restricted to the PCI domain. We also detected a previously unrecognized PCI domain in the eIF3 component eIF3k, a protein whose 3D-structure has been determined recently. By using profile-guided alignment...

• Type: Journal
• Year: 2005
• Where: BMCBI
• Authors: Hartmut Scheel, Kay Hofmann
• Keywords: BMCBI 2005, PCI Domain, PCI Proteins, Proteasome