Lecture 8 cell biology

• What are the three stages of cell signaling?

  Reception, Transduction, Response

  
• What are the three classes of cell-surface receptors?

  • Ion-channel-linked receptors
  • G-protein-linked receptors
  • Enzyme-linked receptors

  
• What is the role of G-proteins in cell signaling?

  They are crucial for signal transduction
• Who won the Nobel Prize in Physiology or Medicine in 1994?

  Alfred G. Gilman and Martin Rodbell
• What was the 1994 Nobel Prize awarded for?

  Discovery of G-proteins in signal transduction
• What is the significance of signal transduction in the nervous system?

  It is crucial for communication between neurons
• Who were the Nobel Prize winners in Physiology or Medicine in 2000?

  Arvid Carlsson, Paul Greengard, Eric R Kandel
• What is synthesized by adenylyl cyclase from ATP?

  Cyclic AMP

  
• What happens to cyclic AMP after it is produced?

  It is rapidly hydrolyzed by phosphodiesterases

  
• What does the fluorescence change indicate in cultured nerve cells?

  Concentration levels of cAMP
• What are the functions of receptor tyrosine kinases (RTKs)?

  • Cell division
  • Differentiation
  • Growth control
  • Immune responses
  • Development

  
• What is Src in relation to tyrosine kinases?

  A non-receptor tyrosine kinase

  
• What do SH2 domains primarily bind to?

  Phosphotyrosines

  
• What is the role of SH3 domains?

  They interact with proline-rich peptide targets

  
• How does excessive activation of RTKs affect cells?

  It can lead to uncontrolled growth and cancer
• What are the classes of receptor tyrosine kinases (RTKs)?

  1. EGFreceptor, NEU/HER2, HER3
  2. Insulin receptor
  3. PDGF
  4. FGF
  5. VEGF
  6. Eph
• What activates receptor tyrosine kinases?

  Conformational change and dimerization

  
• What is the function of the SH1 domain in Src?

  Catalytic domain with kinase activity

  
• What is the role of Ras in cellular signaling?

  Involved in cell growth and differentiation

  
• What happens when Ras proteins are mutated?

  They remain in the ON state, causing cancer
• What is the significance of receptor tyrosine kinases in embryonic development?

  They lead to cell division and differentiation

  
• What is the role of the insulin receptor kinase (IRK)?

  It binds insulin and autophosphorylates

  
• What does the PDGF receptor activate?

  Enzymes like PI3 kinase and Phospholipase C
• What is the role of Eph receptors?

  Mediates cell-cell contacts and migration

  
• What is the structure of receptor tyrosine kinases?

  Single membrane-spanning proteins
• What is the consequence of losing function at a checkpoint in cell signaling?

  Developmental defects and cancer
• How do receptor tyrosine kinases amplify signaling effects?

  By downstream signaling elements

  
• What does the Insulin Receptor Kinase (IRK) bind to?

  Insulin

  
• What process does IRK undergo after binding insulin?

  Autophosphorylation

  
• What does IRK activate through tyrosine phosphorylation?

  Substrates including IRS-1

  
• What is the role of PDGF Receptor?

  • Binds Platelet Derived Growth Factor
  • Activates enzymes by tyrosine phosphorylation
  • Involved in cellular proliferation, differentiation, and survival

  
• What are the functions of EGF Receptor?

  • Binds Epidermal Growth Factor
  • Promotes cellular proliferation, differentiation, and survival
  • Significant in development and cancer maintenance

  
• What role do Eph receptors play in the body?

  Mediates cell-cell contacts

  
• What is the Eph Receptor family originally isolated from?

  Erythropoietin producing carcinoma
• What are the functions of the Insulin Receptor Kinase (IRK) upon activation?

  • Triggers signaling pathways
  • Activates phosphatidylinositol 3-hydroxy kinase
  • Activates Grb2 and Sos to activate Ras
  • Activates PI-PLC

  
• How do most receptor tyrosine kinases (RTKs) exist in resting cells?

  As monomers

  
• What is the primary function of receptor protein-tyrosine kinases?

  Transmit signals across the plasma membrane

  
• What happens when the external domain of a receptor tyrosine kinase interacts with a ligand?

  It up-regulates the intracellular catalytic domain

  
• What is the first RTK associated with cancer?

  Eph receptor kinase

  
• What are the effects of Eph receptor kinase signaling?

  • Angiogenesis
  • Proliferation
  • Cell-cell adhesion
  • Cell-matrix adhesion