Cell Motility and Chemotaxis Notes
Cell Motility and Chemotaxis
- Importance of cell motility and chemotaxis:
- Development
- Wound healing
- Infection
- Neuronal pathfinding
- Mechanisms:
- Actin-based cell motility and chemotaxis
- Microtubule-based cell motility and chemotaxis
Overview of Cell Movement
- External Signals:
- Soluble factors
- Interactions with other cells
- Extracellular matrix components
- These signals trigger signal transduction pathways within the cell's cytosol, ultimately affecting the cytoskeleton.
- Cytoskeleton's Role:
- Organization and movement of organelles
- Cell shape, overall movement, and contraction
Chemotaxis
- Chemotaxis is the ability of a cell to sense a directional signal and move towards or away from it.
- Dictyostelium discoideum:
- Example of chemotaxis, aggregating in response to cAMP.
- Life cycle: Free-living amoeba reproduce, aggregate in response to cAMP, form a motile slug, and eventually a fruiting body with spores.
Importance of Chemotaxis in the Human Body
- Directed cell movements during development
- Gastrulation
- Neural crest migration
- Primordial germ cell migration
- Immune surveillance
- Phagocytosis of pathogens
- Inflammatory response to injury
- Wound healing
Neutrophil Chemotaxis Example
- Neutrophils chase, catch, and phagocytose bacteria.
- Bacteria secrete fMet-Leu-Phe (fMLP), a tri-peptide.
- fMLP is sensed by receptors on the neutrophil plasma membrane.
- Neutrophils