Cell Motility and Chemotaxis Lecture Notes

Cell Motility and Chemotaxis

• Importance in:
  • Development
  • Wound healing
  • Infection
  • Neuronal pathfinding
• Mechanisms:
  • Actin-based
  • Microtubule-based

Overview of Cell Movement

• External signals (soluble factors, other cells, ECM) trigger:
  • Signal transduction pathways within the cytosol.
  • This impacts the cytoskeleton which influences:
    • Organelle organization and movement
    • Cell shape, movement, and contraction

Dictyostelium discoideum and Chemotaxis

• Dictyostelium discoideum aggregates in response to cAMP.
  • Changes from free-living amoeba to aggregation, forming a motile slug, and finally a fruiting body with spores.

Chemotaxis Defined

• Chemotaxis: The ability to sense and move towards or away from a directional signal.
• Example: Dictyostelium Discoideum moving towards a cAMP source.

Importance of Chemotaxis in the Human Body

• Development: Gastrulation, neural crest migration, primordial germ cell migration.
• Immune surveillance: Phagocytosis of pathogens.
• Inflammation: Lymphocyte migration.
• Wound healing: Fibroblast migration.

Neutrophil Chemotaxis

• Neutrophil chasing and phagocytosing a bacterium.
• Bacteria secrete fMet-Leu-Phe (fMLP), sensed by neutrophil receptors.
• Neutrophils