CD287 TLR7( toll-like receptor 7)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Macrophage
Spleen
Placenta
Brain
Stomach
Small intestine
Lung
Dendritic Cell
B Cell

Expression
CD287  is strongly expressed in predominantly the endosomes of plasmacytoid dendritic cells, B cells and myeloid dendritic cells.  CD287 is expressed on mRNA and upregulated macrophages but not in monocytes nor dendritic cell precursors.  Expression is in the spleen, breast milk, placenta, brain, stomach, small intestine, lung but there is a lower expression in lymph node and tonsil.

Structure
MOLECULAR FAMILY NAME: Belongs to the Toll-like receptor family.

CD287 is a single-pass type-1 1023 aa transmembrane glycoprotein.  It contains a 26 aa signal sequence, an 813 aa extracellular domain which contains 27 leucine-rich repeats (LRR) capped at each end by N- and C-terminal motifs and 14 potential N-linked glycosylation sites, a 21 aa transmembrane domain and an 189 aa intracellular cytoplasmic domain which contains a Toll/IL-1R domain which interacts with the adaptor molecule myeloid differentiation primary response 88 (MyD88).  The LRRs form a "horseshoe" shaped structure which is the ligand binding domain.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

CD287 has 14 potential N-linked glycosylation sites.

Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD287

CD287 binds MyD88 via their TIR cytoplasmic domains.

Function

CD287 acts as a receptor for and is activated by viral single-stranded RNA (ssRNA) which enters the cell via the endosomal pathway.  It forms part of the innate defence mechanism against infection by double-stranded (dsRNA) and single-stranded viruses.  The anti-viral response to dsRNA viruses is thought to be in part due to CD287 recognition of de novo synthesized ssRNA that accumulates during viral replication within the cell cytoplasm.  CD287 plays a fundamental role in pathogen recognition and activation of innate immunity and response to microbial agents.  TLRs are highly conserved from Drosophilia to humans and share structural and functional similarities.  They recognize pathogen-associated molecular patterns (PAMPs) that are expressed on infectious agents, and mediate the production of cytokines necessary for the development of effective immunity.  They participate in the innate immune response to microbial agents.  CD287 mediated signaling is MyD88 dependent and leads to the release of pro-inflammatory cytokines, particularly IFN-1 and an anti-viral response.  CD287 acts via MyD88 and TRAF6, leading to NF-κB activation, cytokine secretion and the inflammatory response.  Recent studies have implicated CD287 in the development of an autoimmune response to self-RNA associated auto-antigens such as nucleoprotein antigens Sm and ribonucleoprotein (RNP).  Sm and RNP are tightly bound to U-rich small nucleotide (sn) RNAs, which are potential ligands of CD287 (and/or CD288).  SnRNA containing antigen-antibody complexes are able to activate B lymphocytes and dendritic cells via CD287 and CD288.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD287 IN INTACT ANIMAL

CD287 agonists such as isatoribine, imiquimod and resiquimod are therapeutic agents used to stimulate an antiviral response in the treatment of HCV infection.  The agonists are currently being assessed as potential adjuvants to vaccines.



Comments
MOLECULAR INTERACTIONS
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD287: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD287: No information.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene51284Q9NYK1
Antibodies

Revised June 25, 2008


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