Intercellular Adhesion Molecule
Intercellular Adhesion Molecule 1 (ICAM1)
ICAM-1 is a type of intercellular adhesion molecule continuously present in low concentrations in the membranes of leukocytes and endothelial cells. Upon cytokine stimulation, the concentrations greatly increase. ICAM-1 can be induced by interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFα) and is expressed by the vascular endothelium, macrophages, and lymphocytes. ICAM-1 is a ligand for LFA-1 (integrin), a receptor found on leukocytes.
When activated, leukocytes bind to endothelial cells via ICAM-1/LFA-1 and then transmigrate into tissues.ICAM-1 has been implicated in subarachnoid hemorrhage (SAH). Levels of ICAM-1 are shown to be significantly elevated in patients with SAH over control subjects in many studies.
Intercellular Adhesion Molecule 2 (ICAM2)
Intercellular adhesion molecule 2 (ICAM2), also known as CD102 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.
This protein may play a role in lymphocyte recirculation by blocking LFA-1-dependent cell adhesion. It mediates adhesive interactions important for antigen-specific immune response, NK-cell mediated clearance, lymphocyte recirculation, and other cellular interactions important for immune response and surveillance.Several transcript variants encoding the same protein have been found for this gene.
Intercellular Adhesion Molecule 3 (ICAM3)
The protein encoded by this gene 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. This protein is constitutively and abundantly expressed by all leucocytes and may be the most important ligand for LFA-1 in the initiation of the immune response.
It functions not only as an adhesion molecule, but also as a potent signalling molecule.Using the cDNA as a probe, Bossy et al. (1994) mapped the ICAM3 gene to 19p13.3-p13.2 by isotopic in situ hybridization. They also mapped the gene to chromosome 19 by PCR amplification of DNAs from somatic cell hybrids. ICAM1 maps to the same region of chromosome 19.
Intercellular Adhesion Molecule 4 (ICAM4)
The LW glycoprotein has recently been renamed ICAM-4 due to its similarity to intercellular adhesion molecule, although exactly which integrins bind to ICAM-4 is subject to controversy. The function of ICAM-4 is not fully understood but appears to be restricted to erythroid cells. During in vitro erythropoesis, LW appears at either the erythroid colony forming stage or later at the proerythroblast stage. A vital part of erythropoesis is the clustering of erythroblasts around bone marrow macrophages to form erythroblastic islands. The erythroblast is then able to remove its nucleus, which is in turn ingested and broken down by the macrophages, to become a mature erythrocyte. During this process ICAM-4 binds to VLA-4, an erythroblast binding site, on adjacent erythroblasts and to αv integrins on macrophages to help stabilise the erythroblastic islands.
Intercellular Adhesion Molecule 5 (ICAM5)
Intercellular adhesion molecule 5 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. This protein is expressed on the surface of telencephalic neurons and displays two types of adhesion activity, homophilic binding between neurons and heterophilic binding between neurons and leukocytes. It may be a critical component in neuron-microglial cell interactions in the course of normal development or as part of neurodegenerative diseases.The 924-amino acid polypeptide comprises an N-terminal signal peptide, an extracellular region with 9 Ig-like domains, a single transmembrane region, and a C-terminal cytoplasmic tail.
ICAM-1 is a type of intercellular adhesion molecule continuously present in low concentrations in the membranes of leukocytes and endothelial cells. Upon cytokine stimulation, the concentrations greatly increase. ICAM-1 can be induced by interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFα) and is expressed by the vascular endothelium, macrophages, and lymphocytes. ICAM-1 is a ligand for LFA-1 (integrin), a receptor found on leukocytes.
When activated, leukocytes bind to endothelial cells via ICAM-1/LFA-1 and then transmigrate into tissues.ICAM-1 has been implicated in subarachnoid hemorrhage (SAH). Levels of ICAM-1 are shown to be significantly elevated in patients with SAH over control subjects in many studies.
Intercellular Adhesion Molecule 2 (ICAM2)
Intercellular adhesion molecule 2 (ICAM2), also known as CD102 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.
This protein may play a role in lymphocyte recirculation by blocking LFA-1-dependent cell adhesion. It mediates adhesive interactions important for antigen-specific immune response, NK-cell mediated clearance, lymphocyte recirculation, and other cellular interactions important for immune response and surveillance.Several transcript variants encoding the same protein have been found for this gene.
Intercellular Adhesion Molecule 3 (ICAM3)
The protein encoded by this gene 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. This protein is constitutively and abundantly expressed by all leucocytes and may be the most important ligand for LFA-1 in the initiation of the immune response.
It functions not only as an adhesion molecule, but also as a potent signalling molecule.Using the cDNA as a probe, Bossy et al. (1994) mapped the ICAM3 gene to 19p13.3-p13.2 by isotopic in situ hybridization. They also mapped the gene to chromosome 19 by PCR amplification of DNAs from somatic cell hybrids. ICAM1 maps to the same region of chromosome 19.
Intercellular Adhesion Molecule 4 (ICAM4)
The LW glycoprotein has recently been renamed ICAM-4 due to its similarity to intercellular adhesion molecule, although exactly which integrins bind to ICAM-4 is subject to controversy. The function of ICAM-4 is not fully understood but appears to be restricted to erythroid cells. During in vitro erythropoesis, LW appears at either the erythroid colony forming stage or later at the proerythroblast stage. A vital part of erythropoesis is the clustering of erythroblasts around bone marrow macrophages to form erythroblastic islands. The erythroblast is then able to remove its nucleus, which is in turn ingested and broken down by the macrophages, to become a mature erythrocyte. During this process ICAM-4 binds to VLA-4, an erythroblast binding site, on adjacent erythroblasts and to αv integrins on macrophages to help stabilise the erythroblastic islands.
Intercellular Adhesion Molecule 5 (ICAM5)
Intercellular adhesion molecule 5 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. This protein is expressed on the surface of telencephalic neurons and displays two types of adhesion activity, homophilic binding between neurons and heterophilic binding between neurons and leukocytes. It may be a critical component in neuron-microglial cell interactions in the course of normal development or as part of neurodegenerative diseases.The 924-amino acid polypeptide comprises an N-terminal signal peptide, an extracellular region with 9 Ig-like domains, a single transmembrane region, and a C-terminal cytoplasmic tail.
