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32 Cards in this Set

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