UPF3B explained

Regulator of nonsense transcripts 3B is a protein that in humans is encoded by the UPF3B gene.^{[1] [2] [3]}

This gene encodes a protein that is part of a post-splicing multiprotein complex involved in both mRNA nuclear export and mRNA surveillance. The encoded protein is one of two functional homologs to yeast Upf3p. mRNA surveillance detects exported mRNAs with truncated open reading frames and initiates nonsense-mediated mRNA decay (NMD). When translation ends upstream from the last exon-exon junction, this triggers NMD to degrade mRNAs containing premature stop codons. This protein binds to the mRNA and remains bound after nuclear export, acting as a nucleocytoplasmic shuttling protein. It forms with Y14 a complex that binds specifically 20 nt upstream of exon-exon junctions. This gene is located on the long arm of chromosome X. Two splice variants encoding different isoforms have been found for this gene.^[3]

Interactions

UPF3B has been shown to interact with UPF2^{[4] [5] [6]} and UPF1.^{[2] [5] [7]}

Further reading

• Cross SH, Charlton JA, Nan X, Bird AP . Purification of CpG islands using a methylated DNA binding column . Nat. Genet. . 6 . 3 . 236–44 . 1994 . 8012384 . 10.1038/ng0394-236 . 12847618 .
• Wilson KF, Fortes P, Singh US, etal . The nuclear cap-binding complex is a novel target of growth factor receptor-coupled signal transduction . J. Biol. Chem. . 274 . 7 . 4166–73 . 1999 . 9933612 . 10.1074/jbc.274.7.4166 . free .
• Kim VN, Kataoka N, Dreyfuss G . Role of the nonsense-mediated decay factor hUpf3 in the splicing-dependent exon-exon junction complex . Science . 293 . 5536 . 1832–6 . 2001 . 11546873 . 10.1126/science.1062829 . 2001Sci...293.1832K . 12018200 .
• Lykke-Andersen J, Shu MD, Steitz JA . Communication of the position of exon-exon junctions to the mRNA surveillance machinery by the protein RNPS1 . Science . 293 . 5536 . 1836–9 . 2001 . 11546874 . 10.1126/science.1062786 . 2001Sci...293.1836L . 389385 .
• Lejeune F, Ishigaki Y, Li X, Maquat LE . The exon junction complex is detected on CBP80-bound but not eIF4E-bound mRNA in mammalian cells: dynamics of mRNP remodeling . EMBO J. . 21 . 13 . 3536–45 . 2002 . 12093754 . 10.1093/emboj/cdf345 . 126094 .
• Lykke-Andersen J . Identification of a human decapping complex associated with hUpf proteins in nonsense-mediated decay . Mol. Cell. Biol. . 22 . 23 . 8114–21 . 2003 . 12417715 . 10.1128/MCB.22.23.8114-8121.2002 . 134073 .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Chiu SY, Serin G, Ohara O, Maquat LE . Characterization of human Smg5/7a: a protein with similarities to Caenorhabditis elegans SMG5 and SMG7 that functions in the dephosphorylation of Upf1 . RNA . 9 . 1 . 77–87 . 2003 . 12554878 . 10.1261/rna.2137903 . 1370372 .
• Gehring NH, Neu-Yilik G, Schell T, etal . Y14 and hUpf3b form an NMD-activating complex . Mol. Cell . 11 . 4 . 939–49 . 2003 . 12718880 . 10.1016/S1097-2765(03)00142-4 . free .
• Schell T, Köcher T, Wilm M, etal . Complexes between the nonsense-mediated mRNA decay pathway factor human upf1 (up-frameshift protein 1) and essential nonsense-mediated mRNA decay factors in HeLa cells . Biochem. J. . 373 . Pt 3 . 775–83 . 2003 . 12723973 . 10.1042/BJ20021920 . 1223536 .
• Lejeune F, Li X, Maquat LE . Nonsense-mediated mRNA decay in mammalian cells involves decapping, deadenylating, and exonucleolytic activities . Mol. Cell . 12 . 3 . 675–87 . 2003 . 14527413 . 10.1016/S1097-2765(03)00349-6 . free .
• Ota T, Suzuki Y, Nishikawa T, etal . Complete sequencing and characterization of 21,243 full-length human cDNAs . Nat. Genet. . 36 . 1 . 40–5 . 2004 . 14702039 . 10.1038/ng1285 . free .
• Kadlec J, Izaurralde E, Cusack S . The structural basis for the interaction between nonsense-mediated mRNA decay factors UPF2 and UPF3 . Nat. Struct. Mol. Biol. . 11 . 4 . 330–7 . 2004 . 15004547 . 10.1038/nsmb741 . 23042477 .
• Lehner B, Sanderson CM . A protein interaction framework for human mRNA degradation . Genome Res. . 14 . 7 . 1315–23 . 2004 . 15231747 . 10.1101/gr.2122004 . 442147 .
• Andersen JS, Lam YW, Leung AK, etal . Nucleolar proteome dynamics . Nature . 433 . 7021 . 77–83 . 2005 . 15635413 . 10.1038/nature03207 . 2005Natur.433...77A . 4344740 .
• Kim YK, Furic L, Desgroseillers L, Maquat LE . Mammalian Staufen1 recruits Upf1 to specific mRNA 3'UTRs so as to elicit mRNA decay . Cell . 120 . 2 . 195–208 . 2005 . 15680326 . 10.1016/j.cell.2004.11.050 . free .
• Gehring NH, Kunz JB, Neu-Yilik G, etal . Exon-junction complex components specify distinct routes of nonsense-mediated mRNA decay with differential cofactor requirements . Mol. Cell . 20 . 1 . 65–75 . 2005 . 16209946 . 10.1016/j.molcel.2005.08.012 . free .
• Kunz JB, Neu-Yilik G, Hentze MW, etal . Functions of hUpf3a and hUpf3b in nonsense-mediated mRNA decay and translation . RNA . 12 . 6 . 1015–22 . 2006 . 16601204 . 10.1261/rna.12506 . 1464862 .

Notes and References

1. Serin G, Gersappe A, Black JD, Aronoff R, Maquat LE . Identification and characterization of human orthologues to Saccharomyces cerevisiae Upf2 protein and Upf3 protein (Caenorhabditis elegans SMG-4) . Mol Cell Biol . 21 . 1 . 209–23 . Jan 2001 . 11113196 . 88795 . 10.1128/MCB.21.1.209-223.2001 .
2. Lykke-Andersen J, Shu MD, Steitz JA . Human Upf proteins target an mRNA for nonsense-mediated decay when bound downstream of a termination codon . Cell . 103 . 7 . 1121–31 . Feb 2001 . 11163187 . 10.1016/S0092-8674(00)00214-2 . free .
3. Web site: Entrez Gene: UPF3B UPF3 regulator of nonsense transcripts homolog B (yeast).
4. Lehner . Ben . Sanderson Christopher M . Jul 2004 . A protein interaction framework for human mRNA degradation . Genome Res. . 14 . 7 . 1315–23 . 1088-9051. 15231747 . 10.1101/gr.2122004 . 442147 .
5. Lejeune . Fabrice . Li Xiaojie . Maquat Lynne E . Sep 2003 . Nonsense-mediated mRNA decay in mammalian cells involves decapping, deadenylating, and exonucleolytic activities . Mol. Cell . 12 . 3 . 675–87 . 1097-2765. 14527413 . 10.1016/S1097-2765(03)00349-6 . free .
6. Lykke-Andersen . Jens . Dec 2002 . Identification of a human decapping complex associated with hUpf proteins in nonsense-mediated decay . Mol. Cell. Biol. . 22 . 23 . 8114–21 . 0270-7306. 12417715 . 10.1128/MCB.22.23.8114-8121.2002 . 134073 .
7. Schell . Thomas . Köcher Thomas . Wilm Matthias . Seraphin Bertrand . Kulozik Andreas E . Hentze Matthias W . Aug 2003 . Complexes between the nonsense-mediated mRNA decay pathway factor human upf1 (up-frameshift protein 1) and essential nonsense-mediated mRNA decay factors in HeLa cells . Biochem. J. . 373 . Pt 3 . 775–83 . 0264-6021. 12723973 . 10.1042/BJ20021920 . 1223536 .