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24 Cards in this Set
- Front
- Back
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Epinephrine pathway
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B-adrenogergic receptor (binds to epinephrine and adrenaline replaces the GDP on g-protein with GTP
activated alpha subunit on g-protein activates adenyl cyclase forms cAMP from ATP protein kinase A is activated and phosphorylates proteins such as phophorylase b kinase (release glucose) |
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Methods of desensitization
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sequestration- store it in cell
receptor downregulation- destroyed within the cell receptor inactivation- active site altered or bound |
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what does b-arrestin do?
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binds to GPCR, blocking its active site and assisting in endocytosis
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ways to bind to DNA
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electrostatic, hydrogen bonding, hydrophobic
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How many combinations are in the major and minor grooves?
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4 and 2
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Which amino acids bind to DNA monomers?
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Asn, Gln, Glu, Lys, Arg
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Name the DNA binding motifs:
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helix-turn-helix, zinc fingers, leucine zippers
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What does a helix-turn-helix do?
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1st helix recognition- bound at major groove, second helix tight fit,
binds as a dimer, has a homeodomain fold |
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What characterizes zinc fingers?
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coordinated to multiple amino acids to stabilize structure,
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What characterizes leucine zippers?
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a number of lys and arg that bind to DNA, leucine zipper motifs have leucines every 7th amino acid
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What does arginine usually bind to?
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guanine
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What does p53 do?
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tumor supressor gene, it's a DNA binding protein that supresses tumor growth, activates transcription of proteins that stop cell cycle, triggers apoptosis
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how is p53 activated?
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by phosphorylation following dna damage
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What is the sequence of action of p53?
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dna damage causes activation and phosphorylation of p53
activated p53 binds to dna upstream of p21 gene to cause transcription p21 is a cell cycle inhibitor protein |
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What are the 3 dna binding regions commonly found in mutated p53?
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L2: l3, lsh (loop strand helix)
all R's |
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How do membranes fuse?
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Recognition event, surfaces come closer together, water remove, local disruption of bilyaer, outer leaflets fuse first, whole bilayer fuses,
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What's a v-snare?
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vesicle on surface of synaptic vesicle (synaptobrevin)
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what's a t-snare?
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target (syntaxin and snap-25)
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how do v-snare and t-snare bring membranes together?
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bind to each other, zip up from the amino termini and draw the two membranes together
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What does complete fusion create?
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a pore
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Botulism:
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Botulism: affects motor neurons and causes muscles to be “over-relaxed”
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Tetanus:
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Tetanus: affects inhibitory neurons and causes uncontrolled and prolonged
muscle contraction |
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what activates p53?
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mdm2
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steps of vesicle fusion
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Steps:
1. Vesicle approaches the membrane as the result of calcium concentration increased triggered by action potential reaching the voltage gated Ca channels 2. V and T snare bind each other and form a helix bundle Æ pull the membranes closer 3. the Water between the two membrane is removed 4. Local disruption of the membranes 5. Fusion of outer leaflet 6. Fusion of the inner leafletÆBilayer fusion 7. release of vesicles’ content into the synaptic clef |
