InterPro domain: IPR035150

The proteasome (or macropain) ( 3.4.25.1 ) is a multicatalytic proteinase complex in eukaryotes and archaea, and in some bacteria, that is involved in an ATP/ubiquitin-dependent non-lysosomal proteolytic pathway [ 1 , 2 , 3 , 4 , 5 ]. In eukaryotes the 20S proteasome is composed of 28 distinct subunits which form a highly ordered ring-shaped structure (20S ring) of about 700kDa. Proteasome subunits can be classified on the basis of sequence similarities into two groups, alpha (A) and beta (B). The proteasome consists of four stacked rings each composed of only alpha or beta subunits, the rings are stacked in the order alpha/beta/beta/alpha. There are seven different alpha subunits and seven different beta subunits [ 6 ].

This entry represents the constitutive proteasome subunit alpha 3 [ 7 ] as found in plants and green algae.

1. Proteasomes: multicatalytic proteinase complexes. Biochem. J. 291 ( Pt 1), 1-10
2. The multicatalytic proteinase of mammalian cells. Arch. Biochem. Biophys. 268, 1-8
3. Proteolysis, proteasomes and antigen presentation. Nature 357, 375-9
4. Proteasomes. Multicatalytic proteinase complexes. Enzyme Protein 47, 187-8
5. Proteasomes: destruction as a programme. Trends Biochem. Sci. 21, 96-102
6. Structure of 20S proteasome from yeast at 2.4 A resolution. Nature 386, 463-71
7. The complete primary structure of mouse 20S proteasomes. Immunogenetics 49, 835-42