ICAM4

Description

The ICAM4 (intercellular adhesion molecule 4 (Landsteiner-Wiener blood group)) is a protein-coding gene located on chromosome 19.

The LW blood group system, first identified in 1940, is distinct from the Rh system. The LW and RhD antigens, although phenotypically related, are genetically independent. The LW antigen is more strongly expressed on RhD positive cells. The LW locus is located on chromosome 19 (19p13.3). The LW antigen is a 40- to 42-kilodalton red cell membrane glycoprotein, now named ICAM-4 due to its similarity to intercellular adhesion molecules. While the exact integrins that bind to ICAM-4 are debated, the protein's function appears to be restricted to erythroid cells. ICAM-4 is expressed during erythropoiesis, starting at either the erythroid colony forming stage or later at the proerythroblast stage. Erythroblast clustering around bone marrow macrophages to form erythroblastic islands is a crucial aspect of erythropoiesis.

ICAM-4, like other ICAM proteins, serves as a binding partner for leukocyte adhesion protein LFA-1 (integrin alpha-L/beta-2). Additionally, ICAM-4 specifically interacts with integrins alpha-4/beta-1 and alpha-V.

ICAM4 is also known as CD242, LW.

Associated Diseases

• alpha thalassemia-intellectual disability syndrome type 1
• hemolytic anemia due to adenylate kinase deficiency
• Heinz body anemia
• delta-beta-thalassemia
• hereditary persistence of fetal hemoglobin-sickle cell disease syndrome