CD299 (C-type lectin domain family 4 member M, CD209 antigen-like protein 1, dendritic cell-specific ICAM-3-grabbing nonintegrin 2, DC-SIGN2, DC-SIGN-related protein, DC-SIGNR, liver/lymph node-specific ICAM-3-grabbing nonintegrin, L-SIGN, CLEC4M, CD209L, CD209L1)
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Function
- pathogen-recognition receptor involved in peripheral immune surveillance in liver
- may mediate endocytosis of pathogens subsequently degraded in lysosomal compartments
- recognizes high mannose N-linked oligosaccharides in a variety of pathogen antigens, including HIV-1 gp120, HIV-2 gp120, SIV gp120, ebolavirus glycoproteins, HCV E2, & human SARS coronavirus protein S (Ca+2-dependent)
- receptor for ICAM3, probably by binding to mannose-like carbohydrates
Structure
- homotetramer
- tandem repeat domain (neck domain) mediates oligermerization
- contains 1 C-type lectin domain
Compartment
- isoform 1, 2, 3: cell membrane
- isoform 5, 6, 7, 10: secreted
Alternative splicing
- named isoforms=11
- additional isoforms seem to exist
- deletion of transmembrane domain encoding exon through alternative splicing produces soluble isoforms
Expression
- predominantly highly expressed in liver sinusoidal endothelial cells & in lymph node
- found in placental endothelium but not in macrophages
- expressed in type 2 alveolar cells & lung endothelial cells
Pathology
- presumably a coreceptor for SARS coronavirus
- receptor for HIV-1 & transmits HIV-1 to permissive T-cells
Polymorphism
- number of repeats in the tandem repeat domain varies between 3-9 per allele thus contributing to a further variability in addition to alternative splicing