ICAM4 - Intercellular adhesion molecule 4 | Elisa - Clia - Antibody - Protein

Background:

ntercellular Adhesion Molecule 4 (ICAM-4) is another member of the ICAM family, but with unique functions compared to ICAM-1, ICAM-2, and ICAM-3. ICAM-4, like other ICAMs, is a glycoprotein. It contains two extracellular immunoglobulin-like domains and a short cytoplasmic tail. ICAM-4 is unique among the ICAM family members because it is primarily expressed on red blood cells (erythrocytes). It plays a role in the adhesion of erythrocytes to endothelial cells in the blood vessel walls. ICAM-4 is involved in erythropoiesis, the process of red blood cell production. It is present on erythroblasts and helps in their maturation. By mediating adhesion between red blood cells and endothelial cells, ICAM-4 may have implications for blood flow and vascular function. Changes in ICAM-4 expression or function have been associated with certain blood disorders, such as sickle cell disease. In sickle cell disease, abnormal hemoglobin causes red blood cells to become rigid and sticky, and ICAM-4 has been implicated in the adhesion of these cells to the endothelium. ICAM-4 has also been studied in the context of malaria. Some research suggests that ICAM-4 may be involved in the adhesion of malaria-infected red blood cells to endothelial cells, contributing to the pathogenesis of the disease.

Classification and Subtypes:

ICAM-4 is one of five members of the ICAM family, which includes ICAM-1, ICAM-2, ICAM-3, ICAM-4, and ICAM-5. These molecules are characterized by their role in cell adhesion and their immunoglobulin-like domain structures.

Function and Biological Significance:

ICAM-4 plays a crucial role in the adhesion of erythrocytes to other cells and extracellular matrix components. It serves several key functions:

• Cell Adhesion: ICAM-4 interacts with integrins, such as alpha4beta1 (VLA-4) and alphaVbeta3, facilitating erythrocyte adhesion to endothelial cells, macrophages, and extracellular matrix proteins.
• Blood Flow Regulation: By mediating adhesion interactions, ICAM-4 helps maintain proper blood flow and vessel integrity, particularly under conditions of stress or injury.
• Immune Response: ICAM-4 can influence immune responses by modulating the interactions between erythrocytes and immune cells, such as macrophages and dendritic cells.

Interactions:

ICAM-4 interacts primarily with integrins, including:

• Alpha4beta1 (VLA-4): This integrin is expressed on leukocytes and mediates their adhesion to endothelial cells and other extracellular matrix components.
• AlphaVbeta3: This integrin is involved in cell adhesion, migration, and signaling and is expressed on various cell types, including endothelial cells and platelets.

Clinical Issues:

Dysregulation of ICAM-4 expression or function can impact various physiological and pathological processes, including:

• Sickle Cell Disease: In conditions like sickle cell disease, altered ICAM-4 interactions can contribute to vaso-occlusion and impaired blood flow, leading to pain and organ damage.
• Malaria: ICAM-4 may play a role in the adhesion of malaria-infected erythrocytes to the vascular endothelium, contributing to the pathogenesis of severe malaria.
• Anemia: Changes in ICAM-4 expression or function can affect erythrocyte lifespan and stability, potentially contributing to anemia or other red blood cell disorders.

Summary:

ICAM-4 is a vital adhesion molecule expressed on erythrocytes, facilitating their interactions with other cells and extracellular matrix components. It plays a significant role in maintaining blood flow and vessel integrity and can influence immune responses. Understanding ICAM-4's interactions and functions provides insights into its involvement in diseases such as sickle cell disease, malaria, and anemia, highlighting its potential as a therapeutic target for these conditions.