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ELAV-like protein 1

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ELAVL1
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesELAVL1, ELAV1, HUR, Hua, MelG, ELAV like RNA binding protein 1, HuR
External IDsOMIM: 603466; MGI: 1100851; HomoloGene: 20367; GeneCards: ELAVL1; OMA:ELAVL1 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001419

NM_010485

RefSeq (protein)

NP_001410

NP_034615

Location (UCSC)Chr 19: 7.96 – 8.01 MbChr 8: 4.34 – 4.38 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

ELAV-like protein 1 or HuR (human antigen R) is a protein that in humans is encoded by the ELAVL1 gene.[5][6]

The protein encoded by this gene is a member of the ELAVL protein family. This encoded protein contains 3 RNA-binding domains and binds cis-acting AU-rich elements in 3' untranslated regions. One of its best-known functions is to stabilize mRNAs in order to regulate gene expression.[7] Various post-translational modifications of HuR influence its subcellular localization and stability of binding to mRNAs.[8]

Structure

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Of the RNA-binding ELAV/Hu family of proteins in mammals, HuR is the only ubiquitously expressed one, whereas the other three are primarily found in neuronal tissue.[9] Having a well-conserved primary structure to its family members, HuR has two adjacent RNA recognition motifs (RRMs) proximal to the N-terminus, followed by a flexible hinge region next to a final RRM at the C-terminus.[5] The RRM domains of HuR each contain two alpha helices with several antiparallel beta sheets in their secondary structure, a 20 amino-acid long N-terminus before RRM1 and RRM2, and a 12 amino acid linker connecting them.[10][11] The hinge region connecting RRM1,2 to RRM3 is 60 amino acids long.[11]

RNA Binding

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The RRM1 domain appears to be the principal RNA-binding portion with RRM2 contributing some more contacts.[11] According to crystal structure studies, RRM1,2 domains correspond to a "moderately specific" predicted consensus sequence.[12][13] Additionally, RRM3 contributes to dimerization and oligomerization of HuR, supporting binding to AU-rich elements of RNA by the other domains, but RRM3 itself has moderate binding strength to RNA.[12] RRM3 has been shown to bind to long poly-A tails and AU-rich RNAs.[14]

Function

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This RNA-binding protein has been found to be involved in a number of valuable cellular processes in mammals, including embryonic development, stress responses, and the immune system.[15] Post-translational modifications of HuR, including phosphorylation, NEDDylation, methylation, and ubiquitination each modulate the localization and expression of the protein in unique ways. Modifications such as methylation and ubiquitination alter the affinity of HuR to RNA.[16] As an important regulator of post-transcriptional regulation, HuR destabilization from the mRNA is associated with degradation of the transcript.[17]

Phosphorylation of HuR can occur by cyclin-dependent kinases (cdks), impacting its localization within the cell in a cell cycle-dependent fashion.[18] Additionally, checkpoint kinase 2 plays a significant role in phosphorylating HuR during genotoxic stress, promoting dissociation of HuR from its target mRNA transcript.[19]

Additionally, the ubiquitination of HuR by an E3 ligase in many cases results in proteasomal degradation. For instance, the esophageal tumor suppressor ECRG2, ubiquitinates HuR during DNA damage, promoting its degradation.[20] However, in other cases, ubiquitination promotes dissociation of HuR from its transcript, such as ubiquitination of certain lysine residues of the RRM3 domain leading to detachment from the mRNA transcript of P21 and other tumor suppressors.[21]

Moreover, as is frequent in other mammalian proteins, HuR is methylated at arginine residues.[22] For instance, protein arginine methyltransferase enzymes (PRMTs) methylate HuR to promote mRNA stabilization of certain target transcripts, such as SIRT1 in HeLa cells.[23]

Cancer

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Although HuR has a vital role in transcriptosomal regulation, there is an apparent up-regulation of HuR in several types of cancer that correlates with a malignant or metastatic status that has increased the relevance of HuR as a potential therapeutic target for a number of cancer studies. The abundance of HuR suggests a tumorigenic promotion of angiogenesis, cellular proliferation, and anti-apoptotic properties in cancer cells, purportedly due to the impact of mRNA stabilization and its ubiquitous presence in human tissue.[24]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000066044Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000040028Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b Ma WJ, Cheng S, Campbell C, Wright A, Furneaux H (April 1996). "Cloning and characterization of HuR, a ubiquitously expressed Elav-like protein". The Journal of Biological Chemistry. 271 (14): 8144–8151. doi:10.1074/jbc.271.14.8144. PMID 8626503.
  6. ^ Ma WJ, Furneaux H (January 1997). "Localization of the human HuR gene to chromosome 19p13.2". Human Genetics. 99 (1): 32–33. doi:10.1007/s004390050305. PMID 9003489. S2CID 32509747.
  7. ^ "Entrez Gene: ELAVL1 ELAV (embryonic lethal, abnormal vision, Drosophila)-like 1 (Hu antigen R)".
  8. ^ Doller A, Pfeilschifter J, Eberhardt W (December 2008). "Signalling pathways regulating nucleo-cytoplasmic shuttling of the mRNA-binding protein HuR". Cellular Signalling. 20 (12): 2165–2173. doi:10.1016/j.cellsig.2008.05.007. PMID 18585896.
  9. ^ Antic D, Keene JD (August 1997). "Embryonic lethal abnormal visual RNA-binding proteins involved in growth, differentiation, and posttranscriptional gene expression". American Journal of Human Genetics. 61 (2): 273–278. doi:10.1086/514866. PMC 1715898. PMID 9311730.
  10. ^ Cléry A, Blatter M, Allain FH (June 2008). "RNA recognition motifs: boring? Not quite". Current Opinion in Structural Biology. 18 (3): 290–298. doi:10.1016/j.sbi.2008.04.002. PMID 18515081.
  11. ^ a b c Wang H, Zeng F, Liu Q, Liu H, Liu Z, Niu L, et al. (March 2013). "The structure of the ARE-binding domains of Hu antigen R (HuR) undergoes conformational changes during RNA binding". Acta Crystallographica. Section D, Biological Crystallography. 69 (Pt 3): 373–380. doi:10.1107/S0907444912047828. PMID 23519412.
  12. ^ a b Pabis M, Popowicz GM, Stehle R, Fernández-Ramos D, Asami S, Warner L, et al. (January 2019). "HuR biological function involves RRM3-mediated dimerization and RNA binding by all three RRMs". Nucleic Acids Research. 47 (2): 1011–1029. doi:10.1093/nar/gky1138. PMC 6344896. PMID 30418581.
  13. ^ Wang X, Tanaka Hall TM (February 2001). "Structural basis for recognition of AU-rich element RNA by the HuD protein". Nature Structural Biology. 8 (2): 141–145. doi:10.1038/84131. PMID 11175903.
  14. ^ Ma WJ, Chung S, Furneaux H (September 1997). "The Elav-like proteins bind to AU-rich elements and to the poly(A) tail of mRNA". Nucleic Acids Research. 25 (18): 3564–3569. PMC 146929. PMID 9278474.
  15. ^ Katsanou V, Milatos S, Yiakouvaki A, Sgantzis N, Kotsoni A, Alexiou M, et al. (May 2009). "The RNA-binding protein Elavl1/HuR is essential for placental branching morphogenesis and embryonic development". Molecular and Cellular Biology. 29 (10): 2762–2776. doi:10.1128/MCB.01393-08. PMC 2682039. PMID 19307312.
  16. ^ Doller A, Pfeilschifter J, Eberhardt W (December 2008). "Signalling pathways regulating nucleo-cytoplasmic shuttling of the mRNA-binding protein HuR". Cellular Signalling. 20 (12): 2165–2173. doi:10.1016/j.cellsig.2008.05.007. PMID 18585896.
  17. ^ Brennan CM, Steitz JA (February 2001). "HuR and mRNA stability". Cellular and Molecular Life Sciences. 58 (2): 266–277. doi:10.1007/PL00000854. PMC 11146503. PMID 11289308.
  18. ^ Kim HH, Abdelmohsen K, Lal A, Pullmann R, Yang X, Galban S, et al. (July 2008). "Nuclear HuR accumulation through phosphorylation by Cdk1". Genes & Development. 22 (13): 1804–1815. doi:10.1101/gad.1645808. PMC 2492667. PMID 18593881.
  19. ^ Yu TX, Wang PY, Rao JN, Zou T, Liu L, Xiao L, et al. (October 2011). "Chk2-dependent HuR phosphorylation regulates occludin mRNA translation and epithelial barrier function". Nucleic Acids Research. 39 (19): 8472–8487. doi:10.1093/nar/gkr567. PMC 3201881. PMID 21745814.
  20. ^ Lucchesi C, Sheikh MS, Huang Y (May 2016). "Negative regulation of RNA-binding protein HuR by tumor-suppressor ECRG2". Oncogene. 35 (20): 2565–2573. doi:10.1038/onc.2015.339. PMID 26434587.
  21. ^ Zhou HL, Geng C, Luo G, Lou H (May 2013). "The p97-UBXD8 complex destabilizes mRNA by promoting release of ubiquitinated HuR from mRNP". Genes & Development. 27 (9): 1046–1058. doi:10.1101/gad.215681.113. PMC 3656322. PMID 23618873.
  22. ^ Bedford MT, Clarke SG (January 2009). "Protein arginine methylation in mammals: who, what, and why". Molecular Cell. 33 (1): 1–13. doi:10.1016/j.molcel.2008.12.013. PMC 3372459. PMID 19150423.
  23. ^ Calvanese V, Lara E, Suárez-Alvarez B, Abu Dawud R, Vázquez-Chantada M, Martínez-Chantar ML, et al. (August 2010). "Sirtuin 1 regulation of developmental genes during differentiation of stem cells". Proceedings of the National Academy of Sciences of the United States of America. 107 (31): 13736–13741. doi:10.1073/pnas.1001399107. PMC 2922228. PMID 20631301.
  24. ^ Abdelmohsen K, Gorospe M (2010). "Posttranscriptional regulation of cancer traits by HuR". Wiley Interdisciplinary Reviews. RNA. 1 (2): 214–229. doi:10.1002/wrna.4. PMC 3808850. PMID 21935886.
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  • PDBe-KB provides an overview of all the structure information available in the PDB for Human ELAV-like protein 1

This article incorporates text from the United States National Library of Medicine ([1]), which is in the public domain.