【背景资料】:Rpt3 is an AAA-ATPase subunit situated in the base sub-complex of the 19S proteasome regulator responsible for protein unfolding and stabilising the interaction of the 19S regulator with the 20S proteasome core. Recombinant protein expressed with N-terminal His-tagBackground:Proteasomes are non-lysosomal proteolytic complexes localised primarily in the cytoplasm and in the nucleus of eukaryotic cells. The 26S proteasome structure is composed of a 20S proteasome catalytic core complex and one or two 19S (PA700) regulatory subcomplexes (26S and 30S complexes respectively). The 20S core comprises two copies of 14 subunits (7 alpha subunits and 7 beta subunits) arranged in a α7β7β7α7 cylindrical array. Proteolytic activities are determined by the β1 (caspase-like), β2 (trypsin-like) and β5 (chymotrypsin-like) subunits, access to which is guarded by the α-subunits. The 19S regulatory unit consists of six ATPase and at least ten non-ATPase subunits that are required for ubiquitinated protein binding, deubiquitination, substrate unfolding and translocation to the 20S catalytic core.Varying catalytic subunit composition (β1, β1i; β2, β2i; β5, β5i) results in a variety of possible subtypes from full constitutive proteasome (β1, β2, β5) through mixed populations to full inducible / immunoproteasome (β1i, β2i, β5i). Alternative regulatory complexes such as the PA200 and 11S proteasome activators confer different substrate specificities and activity compared to the 19S regulator.