ICAM4

ICAM4 (InterCellular Adhesion Molecule 4), also known as LW blood group antigen or Landsteiner-Wiener blood group antigen, is a protein that in humans is encoded by the ICAM4 gene. It is a member of the intercellular adhesion molecule (ICAM) family. All ICAM proteins are type I transmembrane glycoproteins, contain 2-9 immunoglobulin-like C2-type domains, and bind to the leukocyte adhesion LFA-1 protein.

Function

The ICAM4 protein interacts with integrin alpha-4/beta-1 (ITGA4/ITGB1) that is a receptor for fibronectin. The interaction of ICAM4 with ITGA4/ITGB1 enhances the adhesion of lymphocytes, including peripheral blood memory T cells, to vascular endothelium. Distribution of ICAM4 on melanoma cells and exosomes regulates NK cell trafficking in liver metastasis.

Clinical significance

Mutations in the ICAM4 gene are associated with the LW blood group system. The system consists of two antigens, LWa and LWb. Anti-LWa and anti-LWb are naturally occurring antibodies found in the plasma of individuals lacking the corresponding antigens.

See also

• Intercellular adhesion molecule
• Integrin
• NK cell
• LW blood group

References

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External links

• GeneCards: ICAM4

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