Proteasome activator pa28, REG beta subunit <p>PA28 activator complex (also known as 11S regulator of 20S proteasome) is a ring shaped hexameric structure of alternating alpha (PA28alpha) and beta (PA28beta) subunits. The catalytic properties of PA28alpha and PA28beta-activated proteosome are similar [<cite idref="PUB00033208"/>, <cite idref="PUB00033209"/>]. This entry represents the beta subunit. The activator complex binds to the 20S proteasome and stimulates peptidase activity in and ATP-independent manner.</p>