OR5L2
| OR5L2 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Aliases | OR5L2, HSHTPCRX16, HTPCRX16, OR11-153, olfactory receptor family 5 subfamily L member 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | MGI: 3030990; HomoloGene: 72031; GeneCards: OR5L2; OMA:OR5L2 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Olfactory receptor 5L2 is a protein that in humans is encoded by the OR5L2 gene.[5][6]
Olfactory receptors interact with odorant molecules in the nose, to initiate a neuronal response that triggers the perception of a smell. The olfactory receptor proteins are members of a large family of G-protein-coupled receptors (GPCR) arising from single coding-exon genes. Olfactory receptors share a 7-transmembrane domain structure with many neurotransmitter and hormone receptors and are responsible for the recognition and G protein-mediated transduction of odorant signals. The olfactory receptor gene family is the largest in the genome. The nomenclature assigned to the olfactory receptor genes and proteins for this organism is independent of other organisms.[6]
Gene
[edit]OR5L2, also known as OR11-153, is a gene in Homo sapiens (Accession: NM_001004739.1)[7] located in cytogenetic band 11q12.1, spanning 936 base pairs (55,827,219-55,828,154 GRCh38/hg38 assembly) and encodes a 331 amino acid protein[8].
The olfactory receptor gene family is the largest in the genome, with the OR5L2 gene situated within a dense cluster of olfactory receptor genes on chromosome 11. It is plus-strand oriented in the 5′ to 3′ direction relative to the reference sequence. Neighboring genes upstream of OR5L2 consist of OR5L1, OR5D18, while OR5D16 and the OR9M1P pseudogene are located downstream[9]. OR5L2 is a single-exon, intronless gene, similar to its OR counterparts, with the entire coding sequence being transcribed into one continuous RNA[10].
Due the absence of introns, no alternative splicing takes place, nor are there any known isoforms.
Protein
[edit]The OR5L2 protein (Accession: NP_001004739.1)[8] belongs to the olfactory receptor subfamily OR5L, which are Class A (rhodopsin-like) G-protein-coupled receptors with seven transmembrane domains[10]. OR5L2 has a predicted molecular weight of ~35kDa and an isoelectric point of ~8.5 pI[11].
The protein consists of 331 residues, with a composition dominated by hydrophobic amino acids characteristic of a seven transmembrane olfactory GPCR[12]. Leucine, valine, isoleucine, phenylalanine, and methionine together account for over 40% of the sequence, reflecting the membrane-embedded helices[13]. Polar and charged residues are comparatively scarce, with basic residues (K and R) at 7.1% and acidic residues (E and D) at 5.5%, consistent with short cytosolic and extracellular loops rather than large soluble domains[13].
In comparison to other proteins, OR5L2 is markedly more hydrophobic, with over 40% hydrophobic residues–typical for olfactory receptors but far above the proteome average[14]. It also completely lacks tryptophan, an uncommon feature in human proteins and consistent with olfactory receptors’ reliance on other aromatic residues for transmembrane packing[14].
Moreover, there is a conserved “NPL…Y” motif[15] in all orthologs located within transmembrane domain 7, a region critical for maintaining the structural integrity of GPCRs and stabilizing the conformational changes required for receptor activation[16].
Protein Regulation
[edit]Post-Translational Modification
[edit]There is a N-X-S/T consensus motif in OR5L2’s extracellular N-terminus, hinting at a possible functional post-translational N-linked glycosylation site[8]. Functionally, this modification may affect folding and stability, trafficking to the plasma membrane, and ligand binding[17]. This N-X-S/T site at positions 5-8 is preserved across orthologous species–including mammals, birds, reptiles, and amphibians[18]. All other predicted sites, such phosphorylation motifs for protein kinase C (PKC) and casein kinase II (CK2) are positioned on residues that are either within or overlap with the transmembrane helix regions[18]. This likely results in the sites being relatively unused, due to lacking access by ER lumen machinery.
Sub-Cellular Localization
[edit]OR5L2 receives highest predictions for being localized within the endoplasmic reticulum (ER) and plasma membrane, with smaller votes for vacuolar, Golgi, and mitochondrial compartments[19]. Moreover, no nuclear-localization tools were able to detect cleavable signal peptide sites at the N-terminus, which is expected since GPCRs use their first transmembrane helix as a signal anchor for ER insertion[20].
Homology
[edit]Orthologs
[edit]In vertebrates, olfactory receptor (OR) genes are highly conserved and display significant sequence similarity as they are “phylogenetically derived from nine common ancestor genes”[21]. OR5L2 is conserved in mammals, birds, reptiles, and amphibians but absent in fish and invertebrates, suggesting it evolved with terrestrial olfaction.

Paralogs
[edit]OR5L2 has multiple paralogs, but Table 2 highlights those with the highest sequence similarity. The presence of OR5L2 in amphibians, coupled with its absence in earlier aquatic lineages where only OR5L1 is retained, indicates that OR5L2 likely originated from a duplication of OR5L1. This duplication appears to coincide with the evolutionary transition from fully aquatic to semi-terrestrial life, suggesting that OR5L2 emerged as part of the sensory diversification associated with early terrestrial adaptation.

Evolutionary History
[edit]
OR5L2 first appeared in evolutionary history in the late Devonian Period (about 419.2 million and 358.9 million years ago), when the “first four-legged amphibians appeared, indicating the colonization of land by vertebrates”[22]. This olfactory superfamily consists of “390 putatively functional genes and 465 pseudogenes arranged into 18 gene families and 300 subfamilies”[23].
Protein Divergence
[edit]OR5L2 shows moderate divergence across species. In the comparative plot, its trendline falls between cytochrome c (highly conserved) and fibrinogen alpha (highly divergent), indicating an intermediate rate of evolutionary change (Figure 3).
Interacting Proteins
[edit]OR5L2 is predicted to interact with several proteins involved in GPCR signaling. Key partners include β-arrestins (ARRB1, ARRB2), which regulate receptor desensitization and internalization[24], and GRK2, a kinase that phosphorylates activated receptors[25]. Heterotrimeric G-protein subunits (GNAL, GNB1, GNG7, GNG13)[26] and cAMP-dependent kinases (PRKACA, PRKACB, PRKACG)[27] are also predicted interactors, highlighting roles in olfactory signal transduction, phosphorylation, and intracellular trafficking. Predicted interacting proteins of OR5L2, identified through PSICQUIC[28] and STRING[29] analyses, are summarized in Table 3.

Clinical Significance
[edit]Although OR5L2 is classically defined as an olfactory receptor, emerging data indicate broader functional relevance. In the central nervous system (CNS), OR5L2 transcripts are highly expressed in the human amygdala, with levels altered across Alzheimer’s disease, Parkinson’s disease, Creutzfeldt-Jakob disease, and schizophrenia, suggesting a potential role in neural regulatory processes beyond olfaction[30].
Outside the nervous system, OR5L2 is dysregulated in hepatocellular carcinoma (HCC) and appears as a highly connected node within lncRNA-mRNA coexpression networks, implying possible involvement in tumor-associated regulatory pathways[31]. Somatic variants such as p.E207K have been identified in adenocarcinoma samples at varying allele frequencies, though COSMIC currently classifies these mutations as neutral passenger events. OR5L2 has also been reported in non-small cell lung cancers that develop resistance to crizotinib, raising the possibility that alterations in this receptor may contribute to drug-resistance mechanisms through GPCR-linked signaling[32].
Overall, while OR5L2 is not considered a canonical driver gene, its dysregulated expression and recurrent mutations across multiple tissues suggest potential value as a biomarker or modulator of disease-associated pathways.
See also
[edit]References
[edit]- ^ a b c GRCh38: Ensembl release 89: ENSG00000205030 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000075144 – Ensembl, May 2017
- ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ Parmentier M, Libert F, Schurmans S, Schiffmann S, Lefort A, Eggerickx D, Ledent C, Mollereau C, Gerard C, Perret J, et al. (Mar 1992). "Expression of members of the putative olfactory receptor gene family in mammalian germ cells". Nature. 355 (6359): 453–5. Bibcode:1992Natur.355..453P. doi:10.1038/355453a0. PMID 1370859. S2CID 43926.
- ^ a b "Entrez Gene: OR5L2 olfactory receptor, family 5, subfamily L, member 2".
- ^ "OR5L2 olfactory receptor family 5 subfamily L member 2 [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2025-12-22.
- ^ a b c "olfactory receptor 5L2 [Homo sapiens] - Protein - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2025-12-22.
- ^ "OR5L2 olfactory receptor family 5 subfamily L member 2 [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2025-12-22.
- ^ a b de March, Claire A.; Kim, Soo-Kyung; Antonczak, Serge; Goddard III, William A.; Golebiowski, Jérôme (2015). "G protein-coupled odorant receptors: From sequence to structure". Protein Science. 24 (9): 1543–1548. doi:10.1002/pro.2717. ISSN 1469-896X. PMC 4570547. PMID 26044705.
- ^ "Expasy - Compute pI/Mw tool". web.expasy.org. Retrieved 2025-12-22.
- ^ Crasto, Chiquito J. (2010). "Hydrophobicity profiles in G protein-coupled receptor transmembrane helical domains". Journal of Receptor, Ligand and Channel Research. 2010 (3): 123–133. doi:10.2147/JRLCR.S14437. ISSN 1178-699X. PMC 3187720. PMID 21984869.
- ^ a b EMBL-EBI; Institute, European Bioinformatics. "Job Dispatcher homepage | EMBL-EBI". www.ebi.ac.uk. Retrieved 2025-12-22.
- ^ a b Rios, Santiago; Fernandez, Marta F.; Caltabiano, Gianluigi; Campillo, Mercedes; Pardo, Leonardo; Gonzalez, Angel (December 2015). "GPCRtm: An amino acid substitution matrix for the transmembrane region of class A G Protein-Coupled Receptors". BMC Bioinformatics. 16 (1) 206. doi:10.1186/s12859-015-0639-4. ISSN 1471-2105. PMC 4489126. PMID 26134144.
- ^ "Dotlet JS". dotlet.vital-it.ch. Retrieved 2025-12-22.
- ^ Konvicka, Karel; Guarnieri, Frank; Ballesteros, Juan A.; Weinstein, Harel (August 1998). "A Proposed Structure for Transmembrane Segment 7 of G Protein-Coupled Receptors Incorporating an Asn-Pro/Asp-Pro Motif". Biophysical Journal. 75 (2): 601–611. Bibcode:1998BpJ....75..601K. doi:10.1016/S0006-3495(98)77551-4. PMC 1299736. PMID 9675163.
- ^ Esmail, Sally; Manolson, Morris F. (2021-09-01). "Advances in understanding N-glycosylation structure, function, and regulation in health and disease". European Journal of Cell Biology. 100 (7): 151186. doi:10.1016/j.ejcb.2021.151186. ISSN 0171-9335. PMID 34839178.
{{cite journal}}: CS1 maint: article number as page number (link) - ^ a b "ScanProsite". prosite.expasy.org. Retrieved 2025-12-22.
- ^ "PSORT: Protein Subcellular Localization Prediction Tool". www.genscript.com. Retrieved 2025-12-22.
- ^ elifesciences.org http://web.archive.org/web/20240413142143/https://elifesciences.org/articles/40234.pdf. Archived from the original (PDF) on 2024-04-13. Retrieved 2025-12-22.
{{cite web}}: Missing or empty|title=(help) - ^ Aloni, Ronny; Olender, Tsviya; Lancet, Doron (2006-10-01). "Ancient genomic architecture for mammalian olfactory receptor clusters". Genome Biology. 7 (10) R88. doi:10.1186/gb-2006-7-10-r88. ISSN 1474-760X. PMC 1794568. PMID 17010214.
- ^ https://www.britannica.com/science/Devonian-Period.
{{cite web}}: Missing or empty|title=(help) - ^ Olender, Tsviya; Lancet, Doron; Nebert, Daniel W (2008). "Update on the olfactory receptor (OR) gene superfamily". Human Genomics. 3 (1): 87–97. doi:10.1186/1479-7364-3-1-87. ISSN 1479-7364. PMC 2752031. PMID 19129093.
- ^ Ma, Tian-Liang; Zhou, Yong; Zhang, Chen-Yu; Gao, Zi-Ang; Duan, Jia-Xi (June 2021). "The role and mechanism of β-arrestin2 in signal transduction". Life Sciences. 275 119364. doi:10.1016/j.lfs.2021.119364. PMID 33741415.
- ^ Penela, Petronila; Ribas, Catalina; Sánchez-Madrid, Francisco; Mayor, Federico (November 2019). "G protein-coupled receptor kinase 2 (GRK2) as a multifunctional signaling hub". Cellular and Molecular Life Sciences. 76 (22): 4423–4446. doi:10.1007/s00018-019-03274-3. ISSN 1420-682X. PMC 6841920. PMID 31432234.
- ^ Fonin, Alexander V.; Darling, April L.; Kuznetsova, Irina M.; Turoverov, Konstantin K.; Uversky, Vladimir N. (November 2019). "Multi-functionality of proteins involved in GPCR and G protein signaling: making sense of structure–function continuum with intrinsic disorder-based proteoforms". Cellular and Molecular Life Sciences. 76 (22): 4461–4492. doi:10.1007/s00018-019-03276-1. ISSN 1420-682X. PMC 11105632. PMID 31428838.
- ^ Søberg, Kristoffer; Moen, Line Victoria; Skålhegg, Bjørn Steen; Laerdahl, Jon Kristen (2017-07-25). Srinivasan, Narayanaswamy (ed.). "Evolution of the cAMP-dependent protein kinase (PKA) catalytic subunit isoforms". PLOS ONE. 12 (7): e0181091. Bibcode:2017PLoSO..1281091S. doi:10.1371/journal.pone.0181091. ISSN 1932-6203. PMC 5526564. PMID 28742821.
{{cite journal}}: CS1 maint: article number as page number (link) - ^ PSICQUIC. "PSICQUIC View". www.ebi.ac.uk. Archived from the original on 2024-12-03. Retrieved 2025-12-22.
- ^ "STRING: functional protein association networks". string-db.org. Retrieved 2025-12-22.
- ^ Gaudel, Fanny; Guiraudie-Capraz, Gaëlle; Féron, François (2021-06-25). "Limbic Expression of mRNA Coding for Chemoreceptors in Human Brain—Lessons from Brain Atlases". International Journal of Molecular Sciences. 22 (13): 6858. doi:10.3390/ijms22136858. ISSN 1422-0067. PMC 8267617. PMID 34202385.
- ^ Qu, Shuping; Shi, Qiuyuan; Xu, Jing; Yi, Wanwan; Fan, Hengwei (January 2020). "Weighted Gene Coexpression Network Analysis Reveals the Dynamic Transcriptome Regulation and Prognostic Biomarkers of Hepatocellular Carcinoma". Evolutionary Bioinformatics. 16 1176934320920562. doi:10.1177/1176934320920562. ISSN 1176-9343. PMC 7235675. PMID 32523331.
- ^ Kunimasa, Kei; Inoue, Takako; Matsueda, Katsunori; Kawamura, Takahisa; Tamiya, Motohiro; Nishino, Kazumi; Kumagai, Toru (February 2022). "Cytokine Release Syndrome and Immune-Related Pneumonitis Associated With Tumor Progression in a Pulmonary Pleomorphic Carcinoma Treated With Nivolumab Plus Ipilimumab Treatment: A Case Report". JTO Clinical and Research Reports. 3 (2): 100272. doi:10.1016/j.jtocrr.2021.100272. PMC 8763637. PMID 35072122.
{{cite journal}}: CS1 maint: article number as page number (link)
Further reading
[edit]- Fuchs T, Malecova B, Linhart C, et al. (2003). "DEFOG: a practical scheme for deciphering families of genes". Genomics. 80 (3): 295–302. doi:10.1006/geno.2002.6830. PMID 12213199.
- Malnic B, Godfrey PA, Buck LB (2004). "The human olfactory receptor gene family". Proc. Natl. Acad. Sci. U.S.A. 101 (8): 2584–9. Bibcode:2004PNAS..101.2584M. doi:10.1073/pnas.0307882100. PMC 356993. PMID 14983052.
External links
[edit]- OR5L2+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
This article incorporates text from the United States National Library of Medicine, which is in the public domain.