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32 Cards in this Set
- Front
- Back
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global protein regulation occurs at the level of which stage of translation?
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initiation
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what chemical alteration is most commonly responsible for global protein regulation?
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phosphorylation
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does phosphorylation of eIF2 suppress or activate protein translation?
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suppress
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the binding of which protein to eIF2 stimulates the activation of eIF2 via GTP binding?
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eIF-2B
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when is bound GTP hydrolyzed by eIF2?
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Upon release from 40S ribosome
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what occurs when eIF-2 is phosphorylated?
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it binds tightly to eIF-2B and cannot exchange GDP for GTP and thus cannot perform initiation
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does regulation via phosphorylation of eIF-4 stimulate or suppress translation?
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stimulates
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when not in use, what happens to eIF-4E?
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it is bound to 4E-BP
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phosphorylation of 4E-BP does what?
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releases eIF-4E to perform initiation
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what is the name of the protein kinase that phosphorylates 4E-BP?
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mTOR
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mTOR is in a complex with which two other proteins? What 4 things does this complex detect?
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Raptor and LST8; growth factors, amino acids, ATP, and hypoxia
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what is the name of the drug that suppresses mTOR via FKBP-12?
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Rapamycin
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at which AA position is eIF-4E phosphorylated in the salt bridge clamp regulation technique?
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serine 209
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what are the names of the two protein kinases that phosphorylate eIF-4E at Ser 209?
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MNK1 and PKC
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phosphorylation of eIF-4E at Ser 209 does what for its affinity for the 5 guanine cap? Which other eIF-4E AA is involved in the clamp?
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increases; Lys 159
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what is transferrin? How is it internalized by cells?
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iron-transport protein in serum; via transferrin receptor on cell surface
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what is the name for the iron-carrying protein inside cells?
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ferritin
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what happens to ferritin and transferrin receptor levels at iron-replete conditions? At iron-deficient conditions?
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decrease in transferrin receptors and increase in ferritin to store excess; increase in transferrin receptors and decrease in ferritin to release stored iron
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what is the name of the protein which regulates mRNA translation of iron proteins?
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aconitase (IRP-1)
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what is the name for the stem loops present in mRNA's of transferrin receptor and ferritin?
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Iron Response Elements (IRE)
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binding of IRP-1 to IRE of transferrin receptor does what to translation? To IRE of ferritin?
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increases; decreases
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binding of iron to IRP-1 has what effect on protein?
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it cannot bind to IRE on mRNA
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lack of IRP-1 has what effect on translation of transferrin receptor? On ferritin receptor?
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decreases; increases
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what effect do miRNA's have on mRNA's?
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they either repress translation or destabilize mRNA
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miRNA's are transcribed by which protein?
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RNA pol II
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what happens following transcription of miRNA's?
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they fold into special stem-loop structures which marks them for processing in nucleus
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what is the name of the RNAse-containing enzyme in the nucleus that processes transcribed miRNA's?
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Drosha
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after processing by Drosha, what is destiny of miRNA's? which proteins act on them?
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they are transported to cytosol and are cleaved further by Dicer/R2D2
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once cleaved by Dicer/R2D2 in cytosol, what complex does miRNA enter?
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RISC complex
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what occurs if RISC complex has imperfect sequence complementarity to the mRNA? What if the sequence matches perfectly? What is this called?
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translation of mRNA is suppressed; mRNA is cleaved; RNA interference
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what is the current hurdle in RNA interference therapy?
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delivery
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binding to which part of mRNA characterizes specific protein regulation?
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untranslated regions
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