|Protein Name||26S proteasome non-ATPase regulatory subunit 2|
|Ref Sequence ID||NP_001094667.1|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Presence in other biological fluids/tissue/cells||20S and 26S proteasomes have been found in nervous tissue, bovine and rat brain|
|Protein Function||26S proteasome is the principal proteolytic machine responsible for regulated protein degradation in eukaryotic cells; 26S proteasome (Box 1) can be divided in two subcomplexes,the core particle (CP, 20S) and the regulatoryparticle (RP, 19S). The RP receives, assists in deubiquitination,and unfolds ubiquitinated protein substrates, that are subsequently translocated into an enclosed cavity formed by the CP;cellular functions range from general protein homeostasis and stress response to the control of vital processes such as cell division and signal transduction; Ubiquitin modifications target condemned proteins to the proteasome; essential for general protein and amino acid homeostasis and controls a myriad of essential cellular processes, including the cell cycle, DNA replication, transcription,signal transduction, and stress responses. One of the components of the 26S proteasome, a multiprotein complex involved in the ATP-driven degradation of ubiquitinated proteins. This complex plays an important role in the maintenance of protein homeostasis by removing misfolded or damaged proteins.|
|Biochemical Properties||26S proteasome results from the ATP-dependent association of two particles, the 20S proteasome and the 19S complex, constituting the catalytic core and the regulatory component, respectively; stability of the 26S proteasome is maintained by Sem1/DSS1 whihc binds to the Rpn3 subunit of the lid sub-complex; 26S proteasome was highly responsive to ATP and ATPanalogues, the PGPH activity being the most sensitive one to ATPγS; in the purified 26S proteasome, the chymotrypsin-like to trypsin-like activity ratio is considerably greater than that of the 20S proteasome|
|Significance in milk||Higher expression indicate enhanced mammary protein catabolism in cows|
|PTMs||Post translational modification of 26S proteasome has been studied in yeast - phosphorylation, ubiquitination, SUMOylation, N(α)-Myristoylation, Glutathionylation, Succinylation|
| Site(s) of PTM(s) |
|Predicted Disorder Regions||1-67,86-88,623-646|
|TM Helix Prediction||No TM helices|
|Significance of PTMs||Phosphorylation regulates protease and ATPase activity; Ubiquitination regulates protein degradation; SUMOylation regulates protease activation; N(α)-Acetylation regulates of protease activity N(α)-Myristoylation regulates growth|
|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. 4. 5.Zhu Q, Pan P, Chen X, Wang Y, Zhang S, Mo J, Li X, Ge RS. Human placental 3β-hydroxysteroid dehydrogenase/steroid Δ5,4-isomerase 1: Identity, regulation and environmental inhibitors. Toxicology. 2019 Sep 1;425:152253. doi: 10.1016/j.tox.2019.152253. Epub 2019 Jul 25. PMID: 31351905.