chemokine binding

Definition

Target type: molecularfunction

Binding to a chemokine. Chemokines are a family of small chemotactic cytokines; their name is derived from their ability to induce directed chemotaxis in nearby responsive cells. All chemokines possess a number of conserved cysteine residues involved in intramolecular disulfide bond formation. Some chemokines are considered pro-inflammatory and can be induced during an immune response to recruit cells of the immune system to a site of infection, while others are considered homeostatic and are involved in controlling the migration of cells during normal processes of tissue maintenance or development. Chemokines are found in all vertebrates, some viruses and some bacteria. [GOC:ai, GOC:BHF, GOC:rl, PMID:12183377, Wikipedia:Chemokine]

Chemokine binding is a crucial molecular process involved in the regulation of immune cell trafficking and inflammatory responses. Chemokines are small, secreted proteins that act as chemoattractants, guiding the migration of various immune cells, such as leukocytes, towards sites of inflammation or infection. Chemokines exert their effects by binding to specific G protein-coupled receptors (GPCRs) expressed on the surface of target cells. This binding event triggers a signaling cascade within the cell, leading to changes in cell behavior, including chemotaxis (directed migration), adhesion, and activation.

The molecular function of chemokine binding can be described in several steps:

1. **Chemokine Recognition:** Chemokines bind to their cognate receptors through a complex interplay of electrostatic interactions, hydrogen bonds, and hydrophobic interactions. The specific amino acid residues within the chemokine and its receptor determine the specificity and affinity of the interaction.

2. **Conformational Changes:** Upon chemokine binding, the receptor undergoes conformational changes. This structural alteration activates the receptor, leading to the recruitment of intracellular signaling proteins.

3. **Signal Transduction:** The activated receptor initiates a cascade of signaling events. G proteins, particularly the Gαi subunit, are activated, leading to the production of second messengers, such as cAMP and calcium ions. These intracellular signaling molecules mediate a variety of downstream effects, including changes in gene expression, cytoskeletal rearrangements, and the activation of transcription factors.

4. **Cellular Responses:** The signaling cascade triggered by chemokine binding ultimately leads to a range of cellular responses, including:

* **Chemotaxis:** Directed migration of cells towards the source of chemokines, guiding immune cells to sites of inflammation or injury.

* **Adhesion:** Enhanced adhesion of immune cells to endothelial cells, facilitating their recruitment to tissues.

* **Activation:** Activation of immune cells, leading to the release of inflammatory mediators and the initiation of an immune response.

5. **Regulation of Immune Cell Trafficking:** Chemokine binding plays a critical role in orchestrating the trafficking of immune cells during inflammation, immune surveillance, and tissue development. Different chemokines attract specific subsets of immune cells, ensuring the appropriate immune response to various threats.

6. **Pathological Roles:** Dysregulation of chemokine binding can contribute to various pathological conditions, including autoimmune diseases, cancer, and chronic inflammatory disorders.

In summary, chemokine binding is a highly regulated molecular process that is essential for maintaining immune homeostasis. It is crucial for recruiting immune cells to sites of inflammation and for coordinating the immune response to pathogens and injury. Aberrant chemokine signaling can contribute to a variety of disease states.'
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Proteins (2)

Compounds (11)