|Protein Name||Proteasome activator complex subunit 1|
|Amino Acid Lenth||249|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Presence in other biological fluids/tissue/cells||PA28 family members, which are found in higher eukaryotes; identified in soluble extracts of bovine red blood cells; PA28a and b subunits are expressed in many organs, they are particularly abundant in immune tissues and are virtually absent from the brain|
|Protein Function||Also known as PA28, activator of 20s proteasome complex; active PA28 binds to the proteasome to form a protease-activator complex; activators that bind to proteasomes and stimulate the hydrolysis of peptides|
|Biochemical Properties||exist as homo- or heteromeric complexes; presence of three PA28 homologs, called α,ß and ɣ; α and ß subunits form a heteroheptamer, whereas ɣ forms a homoheptamer; PA28 was purified from extracts of rat liver, which had high levels of PA28 protein but no PA28 activity; Carboxypeptidase inactivates PA28; bovine PA28 contain a 'KEKE motif', which is characterized by a high content of alternating lysine and glutamic acid residues;|
|Significance in milk||Higher expression indicate enhanced mammary protein catabolism in cows|
|Bibliography||1. Piccinini, M., Tazartes, O., Mostert, M., Musso, A., DeMarchi, M., & Rinaudo, M. T. (2000). Structural and functional characterization of 20S and 26S proteasomes from bovine brain. Brain Research. Molecular Brain Research, 76(1), 103–114. https://doi.org/10.1016/s0169-328x(99)00337-x. |
2. Sharon, M., Taverner, T., Ambroggio, X. I., Deshaies, R. J., & Robinson, C. V. (2006). Structural organization of the 19S proteasome lid: Insights from MS of intact complexes. PLoS Biology, 4(8), 1314–1323. https://doi.org/10.1371/journal.pbio.0040267.
3. Wei, S.-J., Williams, J. G., Dang, H., Darden, T. A., Betz, B. L., Humble, M. M., … Tennant, R. W. (2008). Identification of a specific motif of the DSS1 protein required for proteasome interaction and p53 protein degradation. Journal of Molecular Biology, 383(3), 693–712. https://doi.org/10.1016/j.jmb.2008.08.044.