regulation of chemotaxis

Definition

Target type: biologicalprocess

Any process that modulates the frequency, rate or extent of the directed movement of a motile cell or organism in response to a specific chemical concentration gradient. [GOC:ai]

Chemotaxis, the directed movement of cells or organisms in response to a chemical gradient, is a fundamental process in biology. It plays a crucial role in various biological phenomena, including immune responses, embryogenesis, and the formation of multicellular structures. This complex and tightly regulated process involves a cascade of events, including signal transduction, receptor activation, and cytoskeletal reorganization. The following steps describe the regulation of chemotaxis:

1. **Sensing the Chemical Gradient:** The initial step in chemotaxis is the detection of a chemical gradient by specialized receptors on the cell surface. These receptors, often G protein-coupled receptors (GPCRs), bind to chemoattractants or chemorepellents, initiating a signaling cascade.
2. **Signal Transduction:** Upon ligand binding, the activated receptor triggers a signaling cascade that relays information to the cell's interior. This cascade typically involves a series of protein interactions, including phosphorylation events and the activation of downstream signaling molecules.
3. **Polarization:** The next crucial step is the establishment of a directional bias in the cell, known as polarization. This involves the asymmetric distribution of signaling molecules and cytoskeletal components, leading to the formation of a leading edge and a trailing edge.
4. **Cytoskeletal Reorganization:** The polarized cell then utilizes its cytoskeleton to generate the forces required for movement. The leading edge, characterized by the polymerization of actin filaments, extends protrusions known as pseudopodia or lamellipodia. These protrusions adhere to the substrate, facilitating cell movement.
5. **Motility:** The coordinated interaction of cytoskeletal elements and adhesion molecules results in cell movement. The cell crawls forward by extending protrusions at the leading edge, adhering to the substrate, and retracting its trailing edge.
6. **Feedback Regulation:** The chemotactic response is finely regulated by feedback mechanisms that ensure proper directionality and prevent overstimulation. These mechanisms include the desensitization of receptors, the internalization of signaling molecules, and the inactivation of downstream effectors.

The precise molecular mechanisms involved in chemotaxis vary depending on the cell type and the specific chemoattractant or chemorepellent involved. However, the fundamental principles of signal transduction, polarization, cytoskeletal reorganization, and feedback regulation are common to all chemotactic processes.'
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Proteins (4)

Compounds (58)