chemokin

Chemokines are a family of small proteins secreted by cells that primarily act as chemoattractants, meaning they signal to and guide the migration of cells. They are crucial regulators of the immune system, playing a vital role in inflammation, immune cell trafficking, and development. Chemokines bind to specific G protein-coupled receptors, known as chemokine receptors, which are expressed on the surface of target cells. This binding initiates a cascade of intracellular signaling events that ultimately leads to directed cell movement.

The chemokine system is composed of over 50 different chemokines and roughly 20 chemokine receptors. They are broadly classified into four main subfamilies (CXC, CC, CX3C, and XC) based on the arrangement of conserved cysteine residues in their amino acid sequence. Each subfamily binds to a distinct set of chemokine receptors. For example, CXC chemokines primarily attract neutrophils, while CC chemokines attract monocytes, lymphocytes, and eosinophils.

Chemokines are produced by a wide variety of cell types, including immune cells like macrophages and dendritic cells, as well as non-immune cells such as endothelial cells and fibroblasts. Their production is often induced by inflammatory signals, infections, or tissue damage. This allows them to recruit the appropriate immune cells to sites of injury or infection, facilitating pathogen clearance and tissue repair.

Beyond their role in inflammation and immunity, chemokines are also implicated in other physiological processes, including angiogenesis, hematopoiesis, and even neuronal development. Dysregulation of chemokine signaling has been linked to various diseases, including autoimmune disorders, cancer metastasis, and chronic inflammatory conditions, making them important therapeutic targets.