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37 Cards in this Set
- Front
- Back
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Features of SP |
Around 20 aa long Basica AAs initially Hydrophobic stretch |
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Blobel and Dobberstein 1975 |
Paper that discovered signal hypothesis |
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P54 of SRP |
Binds SP |
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P9/14 of SRP |
Binds A site |
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P68/72 of SRP |
Binds SRP receptor on ER |
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Simon and Blobel 1991 |
Conductance channel experiment Electrophysiological assay Unplug channel of nascent protein using puromycin- increased conductance Remove the ribosomes- decreased conductance |
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Crowley et al 1993 |
ER translocon is aqueous Used excitatory lysyl-NBD Added to truncated preprolactin If excites for 1ns, it is aqueous If excites for 7-8ns is it hydrophobic |
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Gorlich abd Rapoport 1993 |
Showed SRP, sec61alpha and TRAM are the only things needed for ER import |
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Open to cytosol experiment |
Use iodide to quench NBD fluorescence Add iodide to cytosol and see if iodide decreases fluorescence It doesnt so not open to the cytosol |
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Open to ER lumen experiment |
Add iodide to quench NBD fluorescence Add streptolysin O to degrade ER membrane to let iodide into that side No change in fluorescence intensity with small proteins Change when there are long enough proteins |
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BiP discovery |
Salt wash removed from surface and then added back until gate returns |
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Er channel constituents experiment |
Crosslink truncated preprolactin Found sec61 alpha, SRP, SPase and TRAM use sec mutant class A and complement with missing gene Confirmed it is sec61 which is equivalent to eukaryotic sec61 alpha |
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Mammal non translocon proteins |
SRP receptor and TRAM |
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Yeast non translocon proteins |
SEC62/63p and BiP |
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Co-translational translocon motor |
Uses ATP for translation |
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Bacterial translocon motor |
Pushed in by SecA ATP hydrolysis in the channel |
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Yeast teanslocon motor |
BiP binds protein, binds ATP, interacts with Sec63, hydrolysis of BiP-ATP which pulls in the protein |
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Type 1 membrane protein |
N terminus in ER lume Lateral diffusion when TMD in the channel |
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Type 2 membrane protein |
C terminus in ER lumen Uses TMD as the SP |
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Oligosaccharide transferase function |
Does N linked glycosylation onto Asn residue |
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Dolichol function |
Holds the oligosaccharide until N linked glycosylation |
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Number of NAG, Man and Glc residues |
2 NAG, 9 Man and 3 Glc |
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Calnexin |
Binds oligosaccharide to ensure correct folding Removes a glucose |
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Glucosyl transferase |
Transient binding to folded protein Reattach a Glc residue if incorrectly folded |
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Mannosidase |
Slow acting enzyme that adds a mannose residue |
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ER MBL |
Guide mannose tagged protein to Hrd1 |
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Hrd1 |
ER exit channel for misfolded proteins Has RING domain for ubiquitination |
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COP II direction |
ER to Golgi |
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Cop I direction |
Golgi to ER |
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KDEL motif function |
Exposed at low pH in ER resident proteins transported to Golgi KDEL motif allows recruitment of COP I proteins |
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Rothman et al uncoating |
Add cytosol and unhydrolysable GTPyS --> no uncoating Cytosol and fusion inhibitor NEM shoes uncoating All three shows no uncoating Uncoating requires nucleotides |
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COP I recruitment |
ARF binds GEF to become ARF-GTP, exposes fatty domain of ARF ARF GTP binds in membrane and recruits coatomer and GAP Coatomer recruits cargo receptor |
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COP II proteins |
Sar1-GTP Sec13/31 and Sec23/24 are coatomer |
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Uncoating mechanism |
GAP hydrolyses ARF/Sar1 which removes whole coat |
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Rothman et al fusion |
Cytosol and NEM shows no fusion Add fresh cytosol and fusion occurs Fractionate cytosol and NSF found |
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Fusion mechanism |
V snare on vesicle winds with T snare and 2x Snap 25 on target membrane NSP unwinds snares for future use |
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Rab mechanism |
RabGTP on vesicme binds Rab effector on target membrsne Pulls vesicle the membrane for SNARE interaction Hydrolysis forms RabGDP ehich binds GDI GDI takes rab to correct origin membrane gef in membrane does RabGTP |
