Term
| Where would find an ER signal on a peptide? |
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Definition
| The N terminal end, silly. |
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Term
| What does an ER signal do? |
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Definition
| It causes the translation machinery to hold its horses with translatin' until it makes contact with the ER surface. |
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Term
| Rough ER translation: Where are the peptides going to end up? |
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Definition
| 1. Translocated into the ER lumen 2. ER integral membrane peptide |
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Term
| If a peptide eventually becomes an integral membrane protein of the ER or Golgi, where will it end up? |
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Definition
| The plasma membrane or lysosome membrane, respectively |
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Term
| If a peptide eventually becomes a matrix protein of the ER or Golgi, where will it end up? |
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Definition
| Secreted from the plasma membrane via exocytosis or it will function in the lysosome matrix |
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Term
| SRP - Signal Recognition Particle |
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Definition
| Binds to N' end ER sequence and delays translation until mRNA makes it to ER |
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Term
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Definition
| On ER surface / Binds SRP with mRNA/ribosome complex / Associated with closed translocon / GTPase activity when bound to SRP which opens translocon and detaches ribosome from SRP and SRP from receptor |
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Term
| Co-translation/translocation |
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Definition
| Translation through a translocon channel |
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Term
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Definition
| Cleaves ER signal peptide during co-translation |
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Term
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Definition
| TRANSLOCATION PROTEIN / Has a peptide binding domain and ATPase domain / Binds to peptides (w ADP) and "ratchets" them into ER / disassociates with ATP / Prevents back |
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Term
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Definition
| TRANSLOCATION PROTEIN / Associates with ATP bound BiP and promotes ATP hydrolysis to BiP-ADP, which causes a conformational change and BiP-peptide binding |
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Term
| Type I Membrane Insertion |
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Definition
| Single pass protein / Signal sequence cleaved / C' end faces cytosol |
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Term
| Type II Membrane Insertion |
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Definition
| Single pass protein / Signal sequence NOT cleaved / N' end faces cytosol |
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Term
| Type III Membrane Insertion |
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Definition
| Single pass protein / Signal sequence NOT cleaved / C' end faces cytosol |
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Term
| Type VI Membrane Insertion |
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Definition
| Multipass protein / Possess both SA and STA domains / Remember: Even number of domains, C' and N' on same side; Odd, opposite sides |
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Term
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Definition
| Phosphatidyl Inositol is in membrane / Attached to one or more sugars (PE), which attaches to the C' end of the protein / If protein is GPI linked on extracellular side of plasma membrane, the GPI link was created lumen side of ER |
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Term
| STA - Stop Transfer Anchor Sequence |
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Definition
| On type I Single Pass Proteins: Made of ~22 hydrophobic AA and moves laterally through the translocon and into hydrophobic core of membrane / Rest of peptide translated in cytosol |
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Term
| SA - Signal Anchor Sequence |
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Definition
| In type II and III Single Pass Proteins: Mostly hydrophobic but flanked by positively charged AA, which dictate the orientation of N and C terminal ends / In type II, +++ AA are prior to SA and N' end is cytosolic / In type III, +++ AA are after SA and C' is cytosolic |
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Term
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Definition
| Cleaves protein in lumen side and attaches the new C' end to GPI anchor |
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Term
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Definition
| Aids in protein folding, targeting, stability, and cell to cell contact. |
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Term
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Definition
| Carbohydrate-binding proteins |
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Term
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Definition
| Non-enzymatic mechanism of adding carbohydrates to proteins |
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Term
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Definition
| Carbs added sequentially to -OH groups of Ser or Thr by glycosyl transferases in the Golgi. Ex: ABO blood groups |
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Term
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Definition
| Glycans added as a preformed oligosaccharide to Asn in Asn-X-(Ser/Thr) sequence / This takes place to Asn within ER as peptide is translocated / Important for protein folding / Carb-Protein goes through further processing at Golgi |
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Term
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Definition
| UDP-GluNAc analog - stops glycosylation |
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Term
| Synthesis of Oligosaccharide Precursor for Glycosylation |
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Definition
| 1. Oligosaccharide is synthesized in cytosol and ER lumen: made of 1 Dilichol, 2 GluNAc, 9 Mannose, and 3 Glucose molecules. UDP and GDP sugars are added after that. |
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Term
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Definition
| Backbone of oligosaccharide precursor / When UDP-GluNAc is added UDP loses phosphate to become UMP and phopho-GluNAc is added to backbone / Tunicamycin blocks this first step |
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Term
| Oligosaccharyl transferase |
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Definition
| Transfers oligosaccharide from dolichol phosphate to Asn of N terminal consensus sequence. |
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Term
| PDI - Protein Disulfide Isomerase |
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Definition
| Contains a disulfide bond (oxidized) and reacts with reduced cysteine residues to create protein disulfide bonds / Also can interact with incorrect disulfide bond to rearrange them |
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Term
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Definition
| Oxidizes the formation of new disulfide bonds in PDI |
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Term
| Alpha-1 Antitrypsin Deficiency |
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Definition
| Can cause emphysema or liver disease / Neutrophils use Elastase to move through the extracellualr matrix, but Elastase can damage lungs / A-1AT inhibits Elastase and Trypsin / Disease caused by a point mutation that causes improper folding and cystalline aggregates that damage the liver |
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Term
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Definition
| New cis-Golgi forms from the ER. Previous cis-Golgi becomes medial-Golgi, etc. Retrograde movement of proteins helps mature Golgi components to their proper function. |
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Term
| Golgi: anterograde transport vs retrograde transport |
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Definition
| (anterograde = cisternal maturation / retrograde = retrograde vesicles) ER <--> cis-Golgi <--> medial Golgi <--> trans-Golgi <--> secretory or transport vesicle |
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Term
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Definition
| Coat Protein: 1. ER to cis-Golgi movement 2. Sec23/24 and Sec13/Sec31 complexes, Sec16 3.GTPase: Sar1 / Covers exiting ER vesicle, but falls off once it has pinched off |
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Term
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Definition
| Coat Protein: 1. cis-Golgi to ER, Later to earlier Golgi cisternae 2. Sec23/24 and Sec13/Sec31 complexes, Sec16 3.GTPase: ARF |
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Term
| Clathrin (trans-golgi to endosome) |
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Definition
| Coat Protein: 2. Clathrin, GGA, and AP1 complexes 3.GTPase: ARF |
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Term
| Clathrin (Plasma membrane to endosome) |
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Definition
| Coat Protein: 2. Clathrin and AP2 complexes 3. GTPase: ARF |
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Term
| Clathrin (Golgi to lysosome, melanosome, or platelet vesicles |
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Definition
| Coat Protein: 2. AP3 complexes 3.GTPase: ARF |
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Term
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Definition
| On vesicles from ER / Attach to t SNARES on cis-Golgi / mediate vesicle fusion |
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Term
| What proteins possess a KDEL signal? |
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Definition
| Soluble RESIDENT ER Proteins like BiP and PDI. C' end |
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Term
| And what is a KDEL signal, smartypants? |
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Definition
| Lys-Asp-Glu-Leu: Sorting signal for retrograde transport. KDEL receptors are on both ER and cis Golgi surfaces. |
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Term
| Mechanism of KDEL recptors |
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Definition
| The pH is lower in the cis-Golgi (6.6), which promotes binding of KDEL bouund proteins to receptor. The ER pH is 7.1, which promotes release of KDEL containing sequence. |
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Term
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Definition
| Sar1 or ARF (good boy!) / Can be phosphorylated via Sec12. / N' tail inserts into the donor vesicle through hydrophobic interactions / The GTP bound GTPase causes coat proteins to bind to vesicle, aiding in curvature / Once vesicle forms GTP is cleaved to GDP and GTPase N' tail retracts from membrane and coat proteins decoat to expose v-SNARE |
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Term
| High Mannose Glycosylation |
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Definition
| In the cis-Golgi: Removal of three mannose sugars from (Man)8(GluNAc)2 |
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Term
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Definition
| In the trans-Golgi: Addition of three Galactose and three N-Acetylneuraminic acid |
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Term
| Vesicle Transport from Trans-Golgi Network |
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Definition
| AP binds a cytosolic domain sorting signal, aids in packaging |
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Term
| Vesicle Transport from Trans-Golgi Network to the lysosome |
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Definition
| AP3, ARF, and CARGO SIGNAL: Mannose 6-phosphate |
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Term
| Vesicle Transport from Trans-Golgi Network to the endosome |
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Definition
| AP1, ARF and CARGO SIGNAL: Tyr-X-bulky hydrophobic residue |
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Term
| What proteins are involved in receptor mediated endocytosis? |
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Definition
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Term
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Definition
| Comprised of three heavy (with inherent curvature) and three light chains / Forms a triskellion structure that interweave with other triskellions / Associates with AP |
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Term
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Definition
| M-6-P signal is not attached to hydrolyses bound for lysosomes / UDP-GlcNAc is used as a substrate to add GluNAc phosphate to one of the Mannose sugars catalyzed by the enzyme GlcNAc-a-phosphotransferase. GluNAc is then removed by the Phosphodiesterase. I Cell disease has GlcNAc phosphotransferase enzyme is defective / Also known as mucolipidosis |
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Term
| Lysosomal Storage Disease |
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Definition
| Will possess inclusion bodies due to mislabeled proteins |
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Term
| pseudo-Hurler polydystrophy |
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Definition
| A mild form of I Cell disease |
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Term
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Definition
| Proteins with this sequence can be selectively taken up lysosomes. |
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Term
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Definition
| Membrane derived from the endoplasmic reticulum / Can increase in neural injury |
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Term
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Definition
| Receptor or cargo binds to pit through interactions between its cytosolic domain and the AP2 protein. AP2 interacts with Clathrin. |
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Term
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Definition
| Uses GTP hydrolysis to finish last step of Clathrin-coated vesicle. |
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Term
| ATP-dependent proton pump |
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Definition
| Responsible for the acidification of endosomes into lysosomes |
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Term
| Some important single trans membrane proteins |
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Definition
| Low Density Lipoprotein (LDL), the transferrin receptor, and carious growth factor receptors |
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Term
| Some seven transmembrane receptors |
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Definition
| G-protein coupled receptors |
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Term
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Definition
| Transports cholesterol in the blood and extracelllar fluid to the peripheral tissue / Made of phospholipids with interspersed unesterified cholesterol / In the hydrophobic core, cholesterol is esterified to fatty acids / Apolipoprotein B (ApoB) wraps around the outer surfaces |
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Term
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Definition
| Possesses a ligand-binding domain and Beta-propeller domain / Cytosolic surface has a NPXY sorting sequence that interacts with AP2 to form clathrin coated vesicles / LDL receptor ligand binding domain binds ApoB extracellularly / Once the endosome turns lysosome, the Beta propeller domain becomes positively charged and binds to ligand binding domain, releasing the LDL |
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Term
| Familial Hypercholesterolemia |
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Definition
| Genetic disorder / Elevated LDL cholesterol in the blood / Mutation in LDL receptor / Heterozygous = 2x as much blood LDL / Homozygous = 4x to 6x / Can cause atherosclerotic |
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Term
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Definition
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Term
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Definition
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Term
| Ferrotransferrin Receptor |
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Definition
| At neutral pH Ferrotransferrin has high affinity to its receptor / Internalized by RME in clathrin-AP2 vesicles / Acidification causes release of Fe from Ferrotransferrin / At acidic pH the apotransferrin has high affinity for receptor / Complex recycled back to plasma membrane / Neutral pH = disassociation |
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Term
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Definition
| Involved with invagination / Once monoubiquitinated, it interacts with the ESCRT complex to induce invagination WITHIN THE ENDOSOME |
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Term
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Definition
| Similar to Hrs proteins only process cases evagenation and budding |
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