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Flashcards

Receptors linked to kinases and nuclear receptors

andreatong18 Pharmacology Inglês 18 flashcards

Flashcards do conjunto (18)

  1. 1Receptor Enzymes- Extracellular surface.
    - Intracellular surface.
    - insulin receptor is prototype.
  2. 2Insulin Receptor- Insulin regulates: i) metabolism, ii) gene expression.
    - Extracellular insulin signal -> insulin receptor -> insulin-sensitive metabolic enzymes -> nucleus -> gene transcription.
  3. 3Structure of Kinase-Linked Receptor- 2 identical a-chains.
    - 2 identical B-subunits.
    - Insulin binds at a.
    - PK activity on B-subunit.
    - PK activity transfers phosphoryl group from ATP to OH of tyrosine residues on terget proteins.
  4. 4Sequence of Events # 1- Insulin binds a-chain of receptor.
    - Tyrosine kinase activity of B-Subunit activated.
    - Each aB monomer phosphorylates tyrosine residues on the B-chain of its partner in the dimer.
    - Opens up active site -> tyrosine residues on other proteins can be phosphorylated.
  5. 5Sequence of events # 2- Insulin receptor substrate-1 is a target protein.
    - receptor phosphorylates IRS-1 on tyrosine residues.
    - A tyr-P residue in IRS-1 interacts with a protein called Grb2.
  6. 6Sequence of events # 3- Grb2 binds Sos.
    - Bound Sos catalyses replacement of bound GDP with GTP on a protein called RAS.
    - RAS-GTP can bind and activate a protein kinase -> Raf-1.
  7. 7Sequence of events # 4Raf-1 phosphorylates MEK.
    - MEK-P-P phosphorylates MAPK.
    - MAPK-P-P enters nucleus.
  8. 8Sequence of events # 5- Activate Elk1-P binds SRF.
    - Elk-P-SRF stimulates transcription and translation of genes needed for cell division.
  9. 9What else does phosphorylated IRS-1 do?- IRS-1-P binds PI-3 kinase.
    - Activate PI-3K phosphorylates phosphatidylinositol 4,5-biphosphate.
    - PIP3 binds another protein kinase.
  10. 10# 2- Bound PIP3- PKB phosphorylated by PKD1.
    - PBK can phosphorylate serine and threonine residues on target proteins.
    - GSK3 is active without phosphorylation.
  11. 11# 3active GSK3 phosphorylates glycogen synthase.
    - Non-phosphorylated GS -> active
    - Phosphorylated GS -> Inactive.
    - PKB phosphorylation of GSK3 prevents GSK3 phosphorylation of GS.
  12. 12# 4- Non-phosphorylated GS continues to convert glucose into glycogen.
    - PKB also triggers glucose transporter movement.
    - GluT4 moves from internal vesicles to plasma membranes.
    - Stimulation of blood glucose uptake.
  13. 13SH2 Domain Proteins- Src homology 2.
    - Amino acid sequence of SH2 domains similar to a domain in another protein tyrosine kinase called Src.
    - SH2 domains found in other signalling proteins.
    All bind to tyr-P on another protein.
  14. 14Receptor Kinases- One activated receptor can activate several IRS-1 molecules.
    - IRS-1 can activate any SH2-domain proteins.
  15. 15Nuclear ReceptorsBind to:
    - Steroids
    - Retinoids
    - Thyroid Hormones
    - Vitamin D
  16. 16# 2- Used by steroid and thyroid hormones.
    - Are stimulated in nucleus.
    - active receptor stimulates gene transcription -> specific proteins are produced.
    -> proteins induce cellular effects.
  17. 17# 3- All nuclear receptors have a DNA-binding domain.
    - Ligand binding domain is downstream from DNA-binding domain.
    - Upstream from DNA-binding domain is a region that controls gene transcription.
  18. 18# 4- Steroid binds receptor
    - dimers bind to hormone response elements of nuclear DNA.
    - HREs are 200 bp upstream from target genes.
    - Response is an increase in RNA polymerase activity -> extra mRNA produced.

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Descrição
Pharmacology FlashCards sobre Receptors linked to kinases and nuclear receptors, criado por andreatong18 em 20-10-2013.
Criado por
andreatong18 · out 2013
Atualizado
19 fev 2016
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