Rabbit anti-Human PA28, alpha, CT Antibody from MyBioSource.com

PA281 is a 180kD proteasome activator protein that is highly conserved among species.2,3 The PA28 complex is composed of two homologous subunits,a and b, which have similar catalytic properties and associate to form a hexameric ring4-5 that b binds to both ends of the 20S proteasome.6 PA28 is a strong proteasome activator; its affinity for the proteasome is about 10-fold greater than recombinant PA28b.5 The carboxy terminus of PA28a is necessary for PA28 to bind to and activate the proteasome.7 The activation of the proteasome by PA28 is an interferon-g (IFNg) inducible.8 PA28 is constitutively expressed by antigen presenting cells and is required for presentation of certain major histocompatibility (MHC) class I antigens.9-10 PA28 a/b can enhance antigen processing independently of changes in 20S proteasome subunit composition or assembly.11 Down-regulation of PA28 results in abnormal proteasome activation, and has been implicated in the development of intimal hyperplasia (IH) in animal models.6 Detection of anti-PA28a antibody is significantly higher in serum from patients with systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS), suggesting the importance of an antigen-driven system in the induction of an autoimmune response to PA28 complex.12 Impaired expression of proteasome subunits is involved in the loss of HLA class I expression in human colon cancer cells.13