Chemokines are a family of small cytokines or signaling proteins secreted by cells that induce directional movement of leukocytes, as well as other cell types, including endothelial and epithelial cells.
They are chemotactic cytokines that provide directional cues for the movement of white blood cells such as T cells, monocytes, and neutrophils. Chemokines are signaling proteins secreted by cells of the immune system that stimulate the movement of other cells in response to a chemical stimulus.
They signal through cell surface G protein-coupled heptahelical chemokine receptors and are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes).
Chemokines are a large family of small, secreted proteins that signal through cell surface G protein-coupled heptahelical chemokine receptors.
They are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes). Chemokines are functionally divided into two groups: homeostatic and inflammatory.
Homeostatic chemokines are constitutively produced in certain tissues and are responsible for basal leukocyte migration. Inflammatory chemokines are formed under pathological conditions on pro-inflammatory stimuli such as IL-1, TNF-alpha, and LPS.
Chemokines facilitate leukocyte migration and positioning by binding to receptors located at the target cell surface. To date, 43 chemokines have been identified, binding to 19 different receptors.
The function of chemokines is to generate the movement of cells. Not only this, but their function grants them two key roles: chemokines are implicated in immunological reactions and in the homeostasis of the immune system.
Chemokines and Immunological Reactions
Chemokines are a family of small proteins that play key roles in immunological reactions and homeostasis.
They are secondary pro-inflammatory mediators instigated by primary pro-inflammatory mediators, and they regulate cell movement to keep the health and normal functions of the immune system.
Chemokines attract mononuclear cells to sites of chronic inflammation, and they regulate the chemotactic migration of leukocytes by controlling both cell adhesion and chemotaxis.
One of the most thoroughly characterized CC chemokines is monocyte chemoattractant protein 1 (MCP-1), which is termed a “chemokine ligand”.
MCP-1 attracts mononuclear cells to sites of chronic inflammation, where it plays a role in the pathogenesis of various diseases such as rheumatoid arthritis, multiple sclerosis, and atherosclerosis.
Chemokines also play a role in immune surveillance. They help recruit immune cells to areas where they are needed to fight infections or cancerous cells.
In addition, chemokines can act as growth factors for certain types of cells, such as endothelial cells that line blood vessels. Overall, chemokines are essential for maintaining proper immune function and regulating inflammatory responses.
Chemokines and Homeostasis
Chemokines are a family of small, secreted proteins that signal through cell surface G protein-coupled heptahelical chemokine receptors. They are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes).
Under normal conditions, homeostatic chemokines regulate cellular trafficking by directing cells that express corresponding GPCRs. The role of chemokines in homeostasis also involves the movement of cells by chemotaxis; in this situation, however, chemokines are not released in response to any pathogen.
Chemokines bind to seven transmembrane G protein-coupled receptors (GPCRs) that are expressed by a wide variety of cell types and cause conformational changes in trimeric G proteins that trigger the intracellular signaling pathways necessary for cell movement and activation.
In addition to localizing cells of the immune system to particular compartments, chemokines may be involved in other aspects of tissue homeostasis. Chemokine expression is associated with various diseases such as cancer, autoimmune disorders, and inflammatory diseases.