| Structural highlights
Disease
[UBE3A_HUMAN] Defects in UBE3A are a cause of Angelman syndrome (AS) [MIM:105830]; also known as 'happy puppet syndrome'. AS is characterized by features of severe motor and intellectual retardation, microcephaly, ataxia, frequent jerky limb movements and flapping of the arms and hands, hypotonia, hyperactivity, hypopigmentation, seizures, absence of speech, frequent smiling and episodes of paroxysmal laughter, and an unusual facies characterized by macrostomia, a large mandible and open-mouthed expression, a great propensity for protruding the tongue ('tongue thrusting'), and an occipital groove.[1] [2]
Function
[UBE3A_HUMAN] E3 ubiquitin-protein ligase which accepts ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and transfers it to its substrates. Several substrates have been identified including the RAD23A and RAD23B, MCM7 (which is involved in DNA replication), annexin A1, the PML tumor suppressor, and the cell cycle regulator CDKN1B. Catalyzes the high-risk human papilloma virus E6-mediated ubiquitination of p53/TP53, contributing to the neoplastic progression of cells infected by these viruses. Additionally, may function as a cellular quality control ubiquitin ligase by helping the degradation of the cytoplasmic misfolded proteins. Finally, UBE3A also promotes its own degradation in vivo.[3] [4] [5] [6] [7] [8]
Publication Abstract from PubMed
E6AP is a cellular protein that binds cancer-related papillomaviral E6 proteins. The E6 binding domain, called E6ap, is located on an 18-amino acid segment of E6AP. The corresponding peptide was synthesized and its structure determined by nuclear magnetic resonance spectroscopy. The overall structure of the peptide is helical. A consensus E6-binding sequence among different E6 interacting proteins contains three conserved hydrophobic residues. In the structure of the E6AP peptide, the three conserved leucines (Leu 9, Leu 12, and Leu 13) form a hydrophobic patch on one face of the alpha-helix. Substitution of any of these leucines with alanine abolished binding to E6 protein, indicating that the entire hydrophobic patch is necessary. Mutation of a glutamate to proline, but not alanine, also disrupted the interaction between E6 and E6AP protein, suggesting that the E6-binding motif of the E6AP protein must be helical when bound to E6. Comparison of the E6ap structure and mutational results with those of another E6-binding protein (E6BP/ERC-55) indicates the existence of a general E6-binding motif.
Solution structure determination and mutational analysis of the papillomavirus E6 interacting peptide of E6AP.,Be X, Hong Y, Wei J, Androphy EJ, Chen JJ, Baleja JD Biochemistry. 2001 Feb 6;40(5):1293-9. PMID:11170455[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Scanlan MJ, Gordan JD, Williamson B, Stockert E, Bander NH, Jongeneel V, Gure AO, Jager D, Jager E, Knuth A, Chen YT, Old LJ. Antigens recognized by autologous antibody in patients with renal-cell carcinoma. Int J Cancer. 1999 Nov 12;83(4):456-64. PMID:10508479
- ↑ Malzac P, Webber H, Moncla A, Graham JM, Kukolich M, Williams C, Pagon RA, Ramsdell LA, Kishino T, Wagstaff J. Mutation analysis of UBE3A in Angelman syndrome patients. Am J Hum Genet. 1998 Jun;62(6):1353-60. PMID:9585605 doi:S0002-9297(07)62776-1
- ↑ Kumar S, Talis AL, Howley PM. Identification of HHR23A as a substrate for E6-associated protein-mediated ubiquitination. J Biol Chem. 1999 Jun 25;274(26):18785-92. PMID:10373495
- ↑ Louria-Hayon I, Alsheich-Bartok O, Levav-Cohen Y, Silberman I, Berger M, Grossman T, Matentzoglu K, Jiang YH, Muller S, Scheffner M, Haupt S, Haupt Y. E6AP promotes the degradation of the PML tumor suppressor. Cell Death Differ. 2009 Aug;16(8):1156-66. Epub 2009 Mar 27. PMID:19325566 doi:cdd200931
- ↑ Mishra A, Godavarthi SK, Maheshwari M, Goswami A, Jana NR. The ubiquitin ligase E6-AP is induced and recruited to aggresomes in response to proteasome inhibition and may be involved in the ubiquitination of Hsp70-bound misfolded proteins. J Biol Chem. 2009 Apr 17;284(16):10537-45. Epub 2009 Feb 20. PMID:19233847 doi:M806804200
- ↑ Shimoji T, Murakami K, Sugiyama Y, Matsuda M, Inubushi S, Nasu J, Shirakura M, Suzuki T, Wakita T, Kishino T, Hotta H, Miyamura T, Shoji I. Identification of annexin A1 as a novel substrate for E6AP-mediated ubiquitylation. J Cell Biochem. 2009 Apr 15;106(6):1123-35. PMID:19204938 doi:10.1002/jcb.22096
- ↑ Mishra A, Godavarthi SK, Jana NR. UBE3A/E6-AP regulates cell proliferation by promoting proteasomal degradation of p27. Neurobiol Dis. 2009 Oct;36(1):26-34. Epub 2009 Jul 8. PMID:19591933 doi:S0969-9961(09)00159-4
- ↑ Martinez-Noel G, Galligan JT, Sowa ME, Arndt V, Overton TM, Harper JW, Howley PM. Identification and proteomic analysis of distinct UBE3A/E6AP protein complexes. Mol Cell Biol. 2012 Aug;32(15):3095-106. doi: 10.1128/MCB.00201-12. Epub 2012 May, 29. PMID:22645313 doi:10.1128/MCB.00201-12
- ↑ Be X, Hong Y, Wei J, Androphy EJ, Chen JJ, Baleja JD. Solution structure determination and mutational analysis of the papillomavirus E6 interacting peptide of E6AP. Biochemistry. 2001 Feb 6;40(5):1293-9. PMID:11170455
|
