Technical Data
PA28, alpha, CT (Proteasome Activator 28-alpha subunit)
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 Sjogrens 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

Suitable for use in Western Blot. Other applications not tested.

Recommended Dilution:
Western Blot: 1-3ug/ml
Optimal dilutions to be determined by the researcher.

Storage and Stability:
May be stored at 4C for short-term only. For long-term storage, store at -20C. Aliquots are stable for at least 12 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
PabIgGAffinity Purified
100ug4C (-20C Glycerol)Blue IceHumanRabbit
Synthetic peptide derived from the C-terminal region of the proteasome activator 28-alpha subunit (PA28a, also known as 11s regulator complex alpha subunit (REG-alpha) (11S REG) and Interferon gamma up-regulated I-5111 protein (IGUP I-5111) protein.
Epitope-affinity purified from rabbit antiserum.
Supplied as a liquid in PBS, pH 7.4, 0.1% sodium azide, before the addition of glycerol to 40%.
Reacts with the C-terminal region of mouse, rat, human, crab-eating macaque (monkey) and pig PA28a. On Western blots, it identifies the target band at ~28kD. Faint bands of unknown origin may be observed in some homogenate or lysate preparations. Reactivity has been confirmed with mouse spleen, liver and lung homogenates, as well as with human BC-1 B-lymphocyte lymphoma lysates. Based on amino acid sequence homology, cross-reactivity with rat is expected.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
1. Chu-Ping M, et al. Biochem Biophys Acta 1119:303-311,1992.
2. Jiang H, et al. Immunogenetics 46:93-98,1997.
3. Soza A, et al. FEBS Lett 413:27-34,1997.
4. Faries PL, et al. Ann Vasc Surg 15:628-633,2001.
5. Wilk S, et al. Arch Biochem Biophys 384:174-80,2000.
6. Murata S, et al. EMBO J 20:5898-907,2001.
7. Chu-Ping M, et al. Biol Chem 268:22514-22519,1993.
8. Fabunmi RP, et al. J Cell Sci 114:29-36,2001.
9. Groettrup M, et al. Nature 381:166-168,1996.
10. Kohda K, et al. J Immunol 160:4923-14935,1998.
11. Schwarz K, et al. Eur J Immunol 30:3672-3679,2000.
12. Matsushita M, et al. J Rheumatol 31:252-259,2004.
13. Miyagi T, et al. J Gastroenterol Hepatol 18:32-40,2003.