RAGE (receptor)

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Advanced glycosylation end product-specific receptor

Rendering based on PDB 1PWI.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols AGER ; RAGE
External IDs OMIM600214 MGI893592 HomoloGene883 GeneCards: AGER Gene
RNA expression pattern
PBB GE AGER 210081 at tn.png
PBB GE AGER 217046 s at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 177 11596
Ensembl ENSG00000204305 ENSMUSG00000015452
UniProt Q15109 n/a
RefSeq (mRNA) NM_001136 NM_001271422
RefSeq (protein) NP_001127 NP_001258351
Location (UCSC) Chr 6:
32.15 – 32.15 Mb
Chr 17:
34.6 – 34.6 Mb
PubMed search [1] [2]
Schematic of the relation between an immunoglobulin and RAGE
Schematic of the RAGE gene and its products

RAGE, the Receptor for Advanced Glycation Endproducts is a 35kD transmembrane receptor of the immunoglobulin super family which was first characterized in 1992 by Neeper et al.[1] It is also called "AGER". Its name comes from its ability to bind advanced glycation endproducts (AGE), which include chiefly glycoproteins, the glycans of which have been modified non-enzymatically through the Maillard reaction. In view of its inflammatory function in innate immunity and its ability to detect a class of ligands through a common motif, RAGE is often referred to as a pattern recognition receptor. RAGE also has at least one other agonistic ligand: high mobility group protein B1 (HMGB1). HMGB1 is an intracellular DNA-binding protein important in chromatin remodeling which can be released by necrotic cells passively and by active secretion from macrophages, natural killer (NK) cells and dendritic cells.

The interaction between RAGE and its ligands is thought to result in pro-inflammatory gene activation.[2] Due to an enhanced level of RAGE ligands in diabetes or other chronic disorders, this receptor is hypothesised to have a causative effect in a range of inflammatory diseases such as diabetic complications, Alzheimer's disease and even some tumors.

Isoforms of the RAGE protein, which lack the transmembrane and the signaling domain (commonly referred to as soluble RAGE or sRAGE) are hypothesized to counteract the detrimental action of the full-length receptor and are hoped to provide a means to develop a cure against RAGE-associated diseases.

Gene/polymorphisms[edit]

The human RAGE gene lies within the major histocompatibility complex (MHC) class III region on chromosome 6 and comprises 11 exons interlaced by 10 introns. Total length of the gene is about 1400 base pairs (bp) including the promoter region, which partly overlaps with the PBX2 gene.[3] About 30 polymorphisms are known most of which are single nucleotide polymorphisms (SNP).[4]

RNA/alternative splicing[edit]

The primary transcript of the human RAGE gene (pre-mRNA) is thought to be alternatively spliced. So far about 6 isoforms including the full length transmembrane receptor have been found in different tissues such as lung, kidney, brain etc. Five of these 6 isoforms lack the transmembrane domain and are thus believed to be secreted from cells. Generally these isoforms are referred to as sRAGE (soluble RAGE) or esRAGE (endogenous secretory RAGE). One of the isoforms lacks the V-domain and is thus believed not to be able to bind RAGE ligands.

Structure[edit]

The full receptor consists of 5 domains: The cytosolic domain, which is responsible for signal transduction, the transmembrane domain which anchors the receptor in the cell membrane, the variable domain which binds the RAGE ligands, and two constant domains.

RAGE ligands[edit]

RAGE is able to bind several ligands and therefore is referred to as a pattern-recognition receptor. Ligands which have so far been found to bind RAGE are:

RAGE and disease[edit]

RAGE has been linked to several chronic diseases, which are thought to result from vascular damage. The pathogenesis is hypothesized to include ligand binding, upon which RAGE signals activation of nuclear factor kappa B (NF-κB). NF-κB controls several genes involved in inflammation. RAGE itself is upregulated by NF-κB. Given a condition in which there is a large amount of RAGE ligands (e.g. AGE in diabetes or amyloid-β-protein in Alzheimer's disease) this establishes a positive feed-back cycle, which leads to chronic inflammation. This chronic condition is then believed to alter the micro- and macrovasculature, resulting in organ damage or even organ failure. Diseases that have been linked to RAGE are:[citation needed]

AGE receptors[edit]

Besides RAGE there are other receptors which are believed to bind advanced glycation endproducts. However, these receptors could play a role in removal of AGE rather than in signal transduction as it is the case for RAGE. Other AGE receptors are:

  • SR-A (Macrophage scavenger receptor Type I and II)
  • OST-48 (Oligosaccharyl transferase-4) (AGE-R1)
  • 80 K-H phosphoprotein (Proteinkinase C substrate) (AGE-R2)
  • Galectin-3 (AGE-R3)
  • LOX-1 (Lectin-like oxidized low density lipoprotein receptor-1)
  • CD36

References[edit]

  1. ^ Neeper M, Schmidt AM, Brett J, Yan SD, Wang F, Pan YC, Elliston K, Stern D, Shaw A (July 1992). "Cloning and expression of a cell surface receptor for advanced glycosylation end products of proteins". J. Biol. Chem. 267 (21): 14998–5004. PMID 1378843. 
  2. ^ Bierhaus A, Schiekofer S, Schwaninger M, Andrassy M, Humpert PM, Chen J, Hong M, Luther T, Henle T, Klöting I, Morcos M, Hofmann M, Tritschler H, Weigle B, Kasper M, Smith M, Perry G, Schmidt AM, Stern DM, Häring HU, Schleicher E, Nawroth PP (December 2001). "Diabetes-associated sustained activation of the transcription factor nuclear factor-kappaB". Diabetes 50 (12): 2792–808. doi:10.2337/diabetes.50.12.2792. PMID 11723063. 
  3. ^ Hudson BI, Stickland MH, Futers TS, Grant PJ (June 2001). "Effects of novel polymorphisms in the RAGE gene on transcriptional regulation and their association with diabetic retinopathy". Diabetes 50 (6): 1505–11. doi:10.2337/diabetes.50.6.1505. PMID 11375354. 
  4. ^ Hudson BI, Hofman MA, Bucciarelli L, et al. (2002). "Glycation and diabetes: The RAGE connection". Current Science 83 (12): 1515–1521. 

Further reading[edit]

External links[edit]