induction of positive chemotaxis

Definition

Target type: biologicalprocess

Any process that initiates the directed movement of a motile cell or organism towards a higher concentration in a concentration gradient of a specific chemical. [GOC:ai]

Induction of positive chemotaxis is a fundamental biological process by which cells move towards higher concentrations of attractant molecules. This directed movement is crucial for various physiological functions, including immune responses, development, and wound healing. The process involves a complex interplay of signaling pathways, cytoskeletal rearrangements, and directional movement.

Here is a detailed breakdown of the process:

1. **Chemoattractant Detection:** Cells express specific receptors on their surface that can bind to chemoattractant molecules. When an attractant binds to its receptor, it triggers a signal transduction cascade.

2. **Signal Transduction:** The binding event activates intracellular signaling pathways, typically involving G protein-coupled receptors (GPCRs) and second messengers like cAMP or Ca2+. These signaling pathways can lead to the activation of downstream effector proteins.

3. **Cytoskeletal Rearrangements:** Activated effector proteins influence the organization of the cytoskeleton, particularly the actin filaments. Actin polymerization and depolymerization create protrusions (lamellipodia and filopodia) at the leading edge of the cell, while the rear end of the cell contracts.

4. **Directional Movement:** The coordinated action of protrusions and contractions drives the cell towards the higher concentration of chemoattractant. This movement involves the interplay of motor proteins like myosin, which interact with actin filaments to generate force.

5. **Polarity Establishment:** Positive chemotaxis requires the establishment of a polarized cell, with a defined front and rear end. This polarity is often driven by gradients of signaling molecules and cytoskeletal components, creating a directional bias for cell movement.

6. **Adaptation and Desensitization:** To prevent over-stimulation and maintain responsiveness, cells have mechanisms to adapt to the presence of attractants. This involves desensitization of receptors and downregulation of signaling pathways, ensuring that cells can respond to new gradients of attractants.

Overall, the induction of positive chemotaxis is a highly regulated and dynamic process that involves intricate interactions between signaling pathways, cytoskeletal rearrangements, and cell movement. This sophisticated mechanism allows cells to navigate their environment effectively and respond to external stimuli.
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Proteins (5)

Compounds (20)