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Copyright ©2010 Baishideng.
World J Gastroenterol. Mar 21, 2010; 16(11): 1349-1357
Published online Mar 21, 2010. doi: 10.3748/wjg.v16.i11.1349
Figure 1
Figure 1 Schematic illustration of the ubiquitin proteasome pathway. The 26S proteasome consists of the 20S core capped with the 19S regulatory complexes that recognize ubiquitinated protein substrates designated for proteolysis.
Figure 2
Figure 2 Tumor necrosis factor (TNF) α and interferon (IFN) γ induce formation of immunoproteasome subunits. LMP7, LMP2 and MECL-1 subunits replace the constitutive catalytic subunits β5, β1 and β2, respectively, which shift the catalytic properties of the proteasome to generate MHC-I-binding peptides.
Figure 3
Figure 3 Proteasome interacting proteins (PIPs) involved in unfolding and docking of protein substrates designated for degradation by the proteasome. VCP: Valosin-containing protein.
Figure 4
Figure 4 Illustration of hypothetical chronic ethanol feeding effects in 26S dysfunction. As a result of phosphorylation deregulation, 20S and 19S binding is altered, which causes 26S dysfunction. Total dephosphorylation of proteasome subunits by phosphatases is prevented by 14-3-3 protein sequestration of the 20S proteasome.
Figure 5
Figure 5 Diagram showing the important role of the deubiquitinases in the process of proteasome function and removal of ubiquitinated protein substrates, as well as recycling of free ubiquitin.