Receptor Physiology and Cell Signaling

  1. signaling molecule; can be chemical or physical
  2. where ligand binds; has high affinity and specificity to ligand; ensures target cell responsiveness
  3. translation of external signal into intracellular events which would lead to the desired response;makes use of secondary messengers
    signal transduction
  4. generated in the cell in response to ligand binding to receptor
    signal transduction
  5. ligand is synthesized and secreted then attaches to the same cell that released it
  6. ligand is synthesized and secreted then attaches to neighboring cell in the same tissue
  7. ligand is synthesized and secreted then attaches to distant cells
  8. ligands synthesized by neurons
  9. located in the cytoplasm or nucleus; regulates gene expression
    intracellular receptors
  10. transmembrane proteins; regulates intracellular signaling pathways; faster effects
    cell membrane receptors
  11. Molecules that can be activated by the alpha subunit of G-protein coupled receptors
    adenylyl cyclase

    phospholipase c

    phospholipase a2
  12. adenylyl cyclase pathway:
    adenylyl cyclase converts ATP to cAMP

    cAMP binds to regulatory subunit of PKA

    PKA activated

    translocation to nucleus

    phosphorylation of CREB

    increase of transcription of certain genes 
  13. Phospholipase C as an effector molecule
    PIP-> IP3 and DAG

    IP3 ->  IP3 gated calcium channel -> Ca2+ concentration increase

    Activates PKC -> phosphorylates target proteins 
  14. PLA2 as an effector molecule
    • PLAgenerates arachidonic acid from membrane phospholipids
  15. Pathways for arachidonic acid
    cyclooxygenase pathway(prostaglandins, thromboxanes, prostacyclin)-platelet aggregation and inflammation

    5-lipoxygenase pathway(leukotrienes)-allergic and inflammatory response

    epoxygenase pathway(hete and eet acid)-calcium release and cell proliferation
  16. Catalytic receptors
    receptor guanylyl cyclase

    receptor serine/threonine kinases

    receptor kinases 
  17. receptor guanylyl cyclase

    increased cGMP

    activation of PKG

    phosphorylation of target proteins
  18. Receptor Serine/Threonine Kinases
    TGF-Beta(ligand) -> Smad complexes -> B cell differentiation
  19. Receptor Tyrosine Kinases(RTK) 
    Mitogen Active Protein Kinase(MAPK) Pathway -> nerve growth factor
  20. Phosphoinositide 3 Kinase Pathway
    ligand: insulin
  21. signaling molecule: TGF-Beta
    give receptor class and transcription factor:
    TGF-Beta receptors; smad proteins
  22. signaling molecule: cytokines
    give receptor class and transcription factor:
    cytokine receptors; stat proteins
  23. signaling molecule: growth factors
    give receptor class and transcription factor:
    receptor tyrosine kinase; FoxO
  24. signaling molecule: epinephrine and glucagon
    give receptor class and transcription factor:
    G-protein coupled receptors; CREB
  25. decreased concentration of ligand and decreased signaling would cause...
    termination of sell signaling
Card Set
Receptor Physiology and Cell Signaling
Physiology 1.3