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Ligand. Receptor. Receptor/Ligand Binds to promoter elements in DNA and regulates transcription. Cortisol Receptor is located in the cytosol. Retinoid Receptors are in the nucleus. Nucleus:. Target gene in the nucleus. Promoter. Regulation of Transcription. Primary and Secondary Responses.
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Ligand Receptor
Receptor/Ligand Binds to promoter elements in DNA and regulates transcription Cortisol Receptor is located in the cytosol Retinoid Receptors are in the nucleus Nucleus: Target gene in the nucleus Promoter Regulation of Transcription Primary and Secondary Responses
Promoter Promoter Activation of transcription Inhibition of transcription
adenylyl G protein cyclase receptor extracellular space bg a membrane cytosol GDP ligand GTP ATP cAMP Pi
Regulation of Transcription P CREB CRE
Some G protein linked receptors linked to Gq activate Ca2+ signaling PIP2 plays an important role in Ca2+ signaling PIP2 PI
PKC ER Ca2+ Calcium channel Cleavage of PIP2 gives rise to Ca influx Gq (PLC b)
Calmodulin is a Ca2+ receptor that mediates many Calcium responses
CAM Kinases mediate most Ca2+ responses CAM Kinase II
Regulation of Transcription P CREB CRE cAMP phosphodiesterase and adenylyl cyclase are regulated by CAM Kinases PKA Ca channels Some CAM Kinases are PKA targets CAM Kinases and PKA common targets Regulation of Phosphorylase Kinase by cAMP and Ca
P P P P Ligand binding usually causes dimerization of the receptor EGF EGF outside of the cell Membrane inside of the cell
GRB2 PLC PI3K GAP P P P P Ras pathway P-Tyr binds downstream regulators containing SH2 domains SH2 Domain
GEF G D P G T P G A P Inactive Active Ras superfamily of small GTPases help relay signals from RTKs Stimulus Downstream Signaling Pathways
Drosophila Ras activation GRB2 PLC PI3K GAP P P P P Mammalian Ras activation SH2 Domain (DRK) SOS Ras GTP Downstream pathways
MAP Kinase Pathways can be mediated by members of the Ras superfamily Stimulus Usually Ras superfamily
GRB2 PLC PI3K GAP P P P P Ca2+ signaling can be activated by RTKs via PLC g Ca2+ signaling
ER Ca2+ Calcium channel Cleavage of PIP2 gives rise to Ca influx RTK PLCg
GRB2 PLC PI3K GAP P P P P RTKs can activate PI3-Kinase Other signaling pathways Cell survival
C C C C H H H H 2 2 2 2 C C C C H H H H 2 2 2 2 C C C C C C C C O O O O O O O O O O O O O O O O C C C C H H H H C C C C H H H H 2 2 2 2 C C C C H H H H 2 2 2 2 O O O O O O O O P P P P O O O O - - - - O O O O H H H H O O O O 6 6 6 6 5 5 5 5 4 4 4 4 1 1 1 1 3 3 3 3 2 2 2 2 O O O O H H H H O O O O H H H H PI3 Kinase (PI3K) PI(3)P PhosphatidylInositol(PI) PI(3,4,5)P2 PI(3,4)P2 PI3K PI3K + PI4K +PI5K Cell Survival Pathways Other Signaling Pathways
C C C C H H H H 2 2 2 2 C C C C H H H H 2 2 2 2 C C C C C C C C O O O O O O O O O O O O O O O O C C C C H H H H C C C C H H H H 2 2 2 2 C C C C H H H H 2 2 2 2 O O O O O O O O P P P P O O O O - - - - O O O O H H H H O O O O 6 6 6 6 5 5 5 5 4 4 4 4 1 1 1 1 3 3 3 3 2 2 2 2 P H O O O O H H H H O O O O H H H H P H P S E R A K T P D K 1 ser BAD PI3 Kinase (PI3K) and cell survival pathways PI(3)P PhosphatidylInositol(PI) PI(3,4,5)P2 PI(3,4)P2 PI3K PI3K + PI4K +PI5K
P P P P Tyrosine Kinase (TK) Associated Receptors LIGAND outside of the cell Membrane inside of the cell
Src binds to receptors with and without Tyr Kinase activity Schwartzberg (1998) 17; 1463
GRB2 PLC PI3K P P P P Src Cell proliferation, Gene expression, …
LIGAND P P receptors