Cell Signaling

Principles Module 20

Objectives

  • Be able to describe the types of cell signaling
  • Be able to predict the receptor type based on the ligand
  • Be able to discuss the results of cell signaling

Key points

  • Signaling involves the interaction of a ligand with a receptor
    • ligands are molecules that induce a sensory cell to respond
    • receptors are specific to a particular ligand and initiate signal transduction
  • Signal types are classified based on signaling distance
    • autocrine signals target receptors in same cell
    • paracrine signaling targets cells near the originating cell
    • endocrine signals travel through the circulatory system
  • some signals travel between adjacent cells via gap junctions, synapses
  • location of receptors depends on properties of ligand
    • transmembrane receptors bind to ligand outside cell
      • ion channel-linked, protein kinase, G protein-coupled receptors
    • cytoplasmic / nuclear receptors bind to ligand inside cell
      • steroid hormone receptors
  • reception ā†’ transduction ā†’ response
  • example responses: enzyme activation, gene expression, physiological change

In-class activities

  • Read the paper bundle Innovation in Cannabis Medicineand respond to the following questions:
    • What is the biologiacl basis for the researchers to believe that THC effects on the brain could be separate from its effects on pain?
    • What kind of receptor is the glycine receptor? What kind is the CB1R?
    • Why did the researchers modify the glycine receptor, and what did they conclude?
    • Why did the researchers modify the THC molecule, and what did they conclude from these experiments?