Lipocalin 1

Lipocalin-1 is a protein that in humans is encoded by the LCN1 gene.

LCN1
Available structures PDB Human UniProt search: PDBe RCSB List of PDB id codes 1XKI, 3EYC, 4QAF
Identifiers
Aliases	LCN1, PMFA, TLC, TP, VEGP, lipocalin 1
External IDs	OMIM: 151675; HomoloGene: 48099; GeneCards: LCN1; OMA:LCN1 - orthologs
Gene location (Human) Chr. Chromosome 9 (human) Band 9q34.3 Start 135,521,438 bp End 135,526,540 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in lacrimal gland testicle tongue body of tongue superior surface of tongue olfactory zone of nasal mucosa right uterine tube anterior pituitary hippocampus proper oral cavity n/a More reference expression data BioGPS n/a
Gene ontology Molecular function cysteine-type endopeptidase inhibitor activity zinc ion binding chloride ion binding signaling receptor binding small molecule binding Cellular component extracellular region extracellular exosome extracellular space Biological process retina homeostasis sensory perception of taste response to stimulus proteolysis long-chain fatty acid transport negative regulation of endopeptidase activity transport Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3933 n/a Ensembl ENSG00000160349 n/a UniProt P31025 n/a RefSeq (mRNA) NM_001252617 NM_001252618 NM_001252619 NM_002297 n/a RefSeq (protein) NP_001239546 NP_001239547 NP_001239548 NP_002288 NP_001239546.1 NP_002288.1 n/a Location (UCSC) Chr 9: 135.52 – 135.53 Mb n/a PubMed search n/a
Wikidata
View/Edit Human

The protein encoded by this gene belongs to the lipocalin family. Lipocalins are a group of extracellular proteins that are able to bind lipophiles by enclosure within their structures to minimize solvent contact. This protein may bind hydrophobic ligands and inhibit cysteine proteinases. It may also play a role in taste reception.

Structure

NMR Structure of LCN1

Proteins are classified into the lipocalin family by their 8 antiparallel beta-sheets that form a barrel structure which acts as the binding site for ligands.

Function

Lipocalin-1 (LCN1) is capable of binding a wide variety of lipophilic molecules along with zinc and chloride ions. Because of this feature, LCN1’s main function is thought to be the removal of potentially harmful lipids and lipophilic molecules from the body by binding them. The LCN1-Ligand complex is then imported via Lipocalin-1-Interacting Membrane Receptor (LIMR) so the bound molecule can be broken down safely within the cell. This process of retrieving molecules may impact several processes including pheromone signaling, immunodulation, inflammation, detoxification, tissue development, apoptosis and more.

LCN1 shares three sequence motifs with cystatins which enables LCN1 to act in a similar manner to cystatins as a cysteine proteinase inhibitor. These domains have specifically been shown to bind Papain.

LCN1 also plays a role in stabilizing the lipid layer of the tear film, though the details of this are not yet well understood.

History

Lipocalin-1 was initially thought to be produced exclusively by exocrine glands but has also been found in corticotrophs of the pituitary gland.

Alternate Names: Human Tear Prealbumin, Tear Lipocalin, von Ebner’s Gland Protein

Clinical

When a cell is under stress, due to inflammation, infection, or otherwise, it will produce elevated levels of lipocalin-1 (LCN1). This makes it a potential noninvasive biomarker for various diseases. This potential has been shown in a study of IVF blastocysts, where elevated levels of LCN1 indicated aneuploidy in the blastocyst.

Further reading

• Glasgow BJ, Abduragimov AR, Gasymov OK, Yusifov TN (2002). "Tear Lipocalin: Structure, Function and Molecular Mechanisms of Action". Lacrimal Gland, Tear Film, and Dry Eye Syndromes 3. Advances in Experimental Medicine and Biology. Vol. 506. pp. 555–65. doi:10.1007/978-1-4615-0717-8_78. ISBN 978-1-4613-5208-2. PMID 12613960.
• Redl B, Holzfeind P, Lottspeich F (October 1992). "cDNA cloning and sequencing reveals human tear prealbumin to be a member of the lipophilic-ligand carrier protein superfamily". The Journal of Biological Chemistry. 267 (28): 20282–7. doi:10.1016/S0021-9258(19)88698-2. PMID 1400345.
• Lassagne H, Nguyen VC, Mattei MG, Gachon AM (1995). "Assignment of LCN1 to human chromosome 9 is confirmed". Cytogenetics and Cell Genetics. 71 (1): 104. doi:10.1159/000134073. PMID 7606920.
• Bläker M, Kock K, Ahlers C, Buck F, Schmale H (February 1993). "Molecular cloning of human von Ebner's gland protein, a member of the lipocalin superfamily highly expressed in lingual salivary glands". Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1172 (1–2): 131–7. doi:10.1016/0167-4781(93)90279-m. PMID 7679926.
• Holzfeind P, Redl B (February 1994). "Structural organization of the gene encoding the human lipocalin tear prealbumin and synthesis of the recombinant protein in Escherichia coli". Gene. 139 (2): 177–83. doi:10.1016/0378-1119(94)90752-8. PMID 8112601.
• Lassagne H, Gachon AM (May 1993). "Cloning of a human lacrimal lipocalin secreted in tears". Experimental Eye Research. 56 (5): 605–9. doi:10.1006/exer.1993.1075. PMID 8500570.
• Holzfeind P, Merschak P, Rogatsch H, Culig Z, Feichtinger H, Klocker H, Redl B (October 1996). "Expression of the gene for tear lipocalin/von Ebner's gland protein in human prostate". FEBS Letters. 395 (2–3): 95–8. doi:10.1016/0014-5793(96)01008-3. PMID 8898072. S2CID 22843813.
• van't Hof W, Blankenvoorde MF, Veerman EC, Amerongen AV (January 1997). "The salivary lipocalin von Ebner's gland protein is a cysteine proteinase inhibitor". The Journal of Biological Chemistry. 272 (3): 1837–41. doi:10.1074/jbc.272.3.1837. PMID 8999869.
• Redl B, Wojnar P, Ellemunter H, Feichtinger H (September 1998). "Identification of a lipocalin in mucosal glands of the human tracheobronchial tree and its enhanced secretion in cystic fibrosis". Laboratory Investigation; A Journal of Technical Methods and Pathology. 78 (9): 1121–9. PMID 9759656.
• Gasymov OK, Abduragimov AR, Yusifov TN, Glasgow BJ (November 1999). "Interaction of tear lipocalin with lysozyme and lactoferrin". Biochemical and Biophysical Research Communications. 265 (2): 322–5. doi:10.1006/bbrc.1999.1668. PMID 10558865.
• Wojnar P, Lechner M, Merschak P, Redl B (June 2001). "Molecular cloning of a novel lipocalin-1 interacting human cell membrane receptor using phage display". The Journal of Biological Chemistry. 276 (23): 20206–12. doi:10.1074/jbc.M101762200. PMID 11287427.
• Wojnar P, van't Hof W, Merschak P, Lechner M, Redl B (October 2001). "The N-terminal part of recombinant human tear lipocalin/von Ebner's gland protein confers cysteine proteinase inhibition depending on the presence of the entire cystatin-like sequence motifs". Biological Chemistry. 382 (10): 1515–20. doi:10.1515/BC.2001.186. PMID 11727836. S2CID 44411516.
• Wojnar P, Dirnhofer S, Ladurner P, Berger P, Redl B (March 2002). "Human lipocalin-1, a physiological scavenger of lipophilic compounds, is produced by corticotrophs of the pituitary gland". The Journal of Histochemistry and Cytochemistry. 50 (3): 433–5. doi:10.1177/002215540205000314. PMID 11850445.
• Wojnar P, Lechner M, Redl B (May 2003). "Antisense down-regulation of lipocalin-interacting membrane receptor expression inhibits cellular internalization of lipocalin-1 in human NT2 cells". The Journal of Biological Chemistry. 278 (18): 16209–15. doi:10.1074/jbc.M210922200. PMID 12591932.
• Glasgow BJ, Abduragimov AR, Gassymov OK, Yusifov TN, Ruth EC, Faull KF (2002). "Vitamin e Associated with the Lipocalin Fraction of Human Tears". Lacrimal Gland, Tear Film, and Dry Eye Syndromes 3. Advances in Experimental Medicine and Biology. Vol. 506. pp. 567–72. doi:10.1007/978-1-4615-0717-8_79. ISBN 978-1-4613-5208-2. PMID 12613961.
• Tiffany JM, Nagyová B (2002). "The Role of Lipocalin in Determining the Physical Properties of Tears". Lacrimal Gland, Tear Film, and Dry Eye Syndromes 3. Advances in Experimental Medicine and Biology. Vol. 506. pp. 581–5. doi:10.1007/978-1-4615-0717-8_81. ISBN 978-1-4613-5208-2. PMID 12613963.
• Gasymov OK, Abduragimov AR, Yusifov TN, Glasgow BJ (October 2004). "Interstrand loops CD and EF act as pH-dependent gates to regulate fatty acid ligand binding in tear lipocalin". Biochemistry. 43 (40): 12894–904. doi:10.1021/bi049076o. PMID 15461462.