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18 Cards in this Set
- Front
- Back
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Where do hydrophilic hormones bind?
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(With high affinity) to membrane receptors for downstream effects
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Some examples of second messengers?
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DAG, IP3, Ca2+, cAMP, cGMP
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What does IP3 regulate?
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Induces elevation of cytosolic Ca2+ concentration. IP3Rec on ER membrane.
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In T-lymphocyte, how is movement induced?
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An antigen binds to the T cell receptor, triggering transient elevation of intracellular Ca2+ levels
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What is the PLC signaling cascade?
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GalphaQ--> PLC--> PIP2--> IP3--> (release of Ca2+ from ER) --> (act'n of Ca2+ dep't target prot)
GalphaQ--> PLC--> PIP@--> DAG --> PKC --> Plate downstream prot |
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How do proteins chelate Ca2+?
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Proteins tightly bind Ca2+ at their O atoms (usu Glu and Asp carboxyl groups, which are charged at physiologic pH).
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What is a common universal Ca2+ sensor that activates when 4 Ca2+ bind?
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Calmodulin (CaM). Ca2+ binding to CaM causes a conformational change that increases binding affinity of CaM for target prot
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What does Ca2+-CaM interact with?
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Myosin light chain kinase--> CaM binds its central helix to form a globular conformation
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What are the Ca2+ sensing proteins?
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Calmodulin (universal), Troponin C (in sk and cardiac muscle), Syntaxin (regulates exocytosis), PKC, PLA2 (phospholipd--> ArAc)
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Give a brief outline of Adenylyl Cyclase activation
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ligand binds to either alphaS (stim) or alphaI (inh)
If binds alphaS--> act AC--> ATP converted to cAMP--> act PKA--> Plates downstream |
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What is the pathway for Receptor Guanylyl Cyclase?
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(Using agonist Atrial Natriuretic Peptide ANP) ANP binds RGC--> Dimerization--> Guanylyl Cyclase--> GTP converted to cGMP--> PKG (cGMP dep't prot kinase)--> Plate downstream
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What does ANP do?
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Inhibits Na+ and water re-absorption into kidney
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What is the inactive derivative of cAMP?
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5'-AMP, deactivated via phosphodiesterase (same for cGMP)
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GIve an ex of a ser/thr kinase and what it does
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TGF beta. It controls proliferation, survival, differentiation
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Where does signaling take place in heterotrimeric G prots?
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Signaling is restricted to the PM
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How do you turn off the hormone signal?
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1) Recycling: sequester rec
2) Degrade rec (lysosome) 3) Inact'n of signaling prot at membrane, receptor, or signaling prot via inh prot |
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What is HSP?
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Heat Shocked Protein: a molecular chaperone.
HSP is a transcriptional "repressor"-- holds steroid rec to prevent entry into nucleus until steroid binds--> steroid rec dissociates from HSP--> can enter nucleus |
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What lipophilic hormones are in the cytoplasm, nucleus, and DNA-bound?
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Cytoplasm: glucocorticoids, mineralocorticoids, androgen
Nuclear: estrogen, progesterone DNA bound: thyroid hormone, retinoic acid, vit D |
