ch 9

  1. Where do singals come from
    • Contact dependent
    • Autocrin Signaling
    • Paracrine Signaling
    •       a. synaptic signalling
    • Endocrine Signaling
  2. Protein-protein interactions can be what??
  3. Propagation of signal from one molecule to another mediated via conformational changes from ??
    • 1. Allosteric effects
    • 2. Covalent Modification (ex. phosphorylation)
    • 3. Proximity: protein-protein interactions
  4. How does signaling lead to a change in cellular behavior?
    • Change expression of genes
    • Change activity of cellular enzymes/proteins
  5. What are the Main types of Transmembrane Receptors??
    • Channel-linked receptors
    • Enzymatic receptors
    • G-Protein coupled receptors (GPCRS, 7TMs)
  6. Channel-linked receptors ligand-gated channels are used where ? and Common in??
    • Used in many cell types
    • Common in nervous system responses
  7. Kinase
    type of enyme commonly involved in signal transduction
  8. What are the types of kinases
    • tyrosine kinases
    • serine/threonin kinases
  9. Phosphatases
    Another enzyme type commonly involved in signal trandsuction
  10. Receptor Tyrosine Kinases (RTKs) are found in what??q
    • Insulin
    • Growth Factors
  11. What happens with insulin in Pathway 1??
    increased protein translation Glycogen/Lipid synthesis glucose uptake
  12. What happens with insulin in pathway 2
    increased transcription (genes important for cell division)
  13. Kinase Cascase
    • signal
    • receptor
    • activator (Ras)
    • First kinase (Ras activates MKKK)
    • Second kinase (MKKK plus 3 P)
    • MAP kinase (activation of MK w/3P)
    • Response proteins 
    • Response (cellular response)
  14. What is Ras
    a G-protein 
  15. What does Ras do ??
    • Small GTP binding protein
    • Active when bound to STP
    • Can bind to other proteins and cause conformational change 
    • Mutated in many cancers
  16. RTK inactivation are 
    Protein tyrosin phosphatase (PTP)
  17. What happens to the G-Protein coupled receptors (GPCRs)
    Ligand binds--> heterotrimeric G protein binds GTP ---> effector protein activated ---> second messenger system activated
  18. Second Messangers 
    diffusible small molecules or ions generated or released in response to enzyme activity in signaling pathways
  19. Examples of effector proteins
    • Adenylyl cyclase (cAMP)
    • Phosphlipase C 
    •     Diacylglyerol (DAG)
    •     Inositol trisphoshate (IP3)
    •     CA++
  20. Adenyly Cyclase Generates
    Cyclic AMP (cAMP)
  21. Example of Adenylate Cyclase Regulation
  22. what does Hydrolysis of cAMP do ?
    inactivate signal
  23. Phospholipase C is the generation of 
    DAG and IP3
  24. IP3---> Ca++ Release from ER DAG ---> ______??
    Protein Kinase C activation
  25. What are the Main types of intracellular Receptors??
    • Steroid Hormone Receptors
    • Thyroid Hormone Receptors
    • Nitric Oxide Signaling
  26. What happens when there is Nitric Oxide (NO)?
    Calcium Release------> Smooth Muscle Contraction
  27. What are examples of Second Messengers
    • cyclic nucleotides (ex. cAMP and cGMP)
    • inositol trisphosphate (IP3) and diacylglycerol (DAG)
    • calcium ions (Ca2+)
  28. How can two cells respond differently to the same signal??
    Signal branching
  29. Different receptors can activate ______ _______
    Different pathways
  30. Glucagon
    glucose beeded because of low blood sugar ---> breakdown gylcogen
  31. Epinephrine
    glucose needed to escape -----> breakdown gylcogen
  32. What is down to Turn off Signaling Pathway??
    • Internalization of receptor
    • Dephosphorylation (phosphatase)
    • Hydrolysis of GTP ---> GDP
    • Destruction of 2nd messengers
    •     -cAMP, cGMP (phosphodiesterase)
    •     -Ca++ (re-sequestration)
  33. What is the Signaling Process?
    • 1. Signal sent
    • 2. Receptor/ligand binding---> conformational change
    • 3. Transduction (amplification via 2nd messengers, kinase cascade)
    • 4. Cellular response (change in protein activity, gene expression)
    • 5. Removal of signal
Card Set
ch 9
bio exam2 ch9