cell bio ch 7

what happens to all polypeptride extruded into ER Lumen

will undergo one or more modifications

Binding immunoglobin protein (BiP)

a chaperone proteins that aids in folding, assembly of multiple polypeptides and is important for Unfolded-protein response

glycosylation

preformed by glycosyltransferases (GTs), add oligosaccharides to polypeptides to form glycoproteins, may help stabilize folding

disulfide bidges

preformed by protein disulfide (PDI), may for disulfide bonds or transfer disulfide bonds, help stabilize protein folding

GET

embed tail-anchored polypeptide in ER membrane

GT

attach oligosacchariedes to polpeptide

BiP

assist protein folding

PDI

create or transfer disulfide bridges

signal peptides

cleave N-terminal signal sequence

which method would be most effective in tracking protein movement through clls

fluorescent tags

vesicle formation budding step 1

GDP is swapped for GTP in GTPase

vesicle formation budding step 2

vesicle coat forms on cytosolic side of membrane

vesicle formation budding step 3

neck vesicle is stretched and pinched by dynamin or similar protein

vesicle formation budding step 4

GTP hydolysis frees vesicles from parent

Vesicle formation budding step 5

protein coat disassmebles

COPI transportation

retrograde (ex Golgi to ER)

COPI coat proteins

Coat protein (COPs)

COPII transportation

anterograde (ER to golgi)

COPI GTPase

ARF

COPII coat proteins

SEC (like secretion) proteins

COPII GTPase

Sar1

Clathrin-coated transportation

everywhere else

clathrin-coated coat proteins

clathrin

clathrin-coated GTPase

ARF

what do high levels of unfolded proein cause

BiP to diffuse from Ire1

what happens to Ire1 without BiP

dimerizes and splice the transcript of a transcription factor for a more chaperone proteins

what happens when BiP diffuses from ATF6

allows it to translocate to the cytosol and be cleaved into transcription facotr in the golgi then localized to the nucleus

in the nucleus what do derivatives of ATF6 act as

transcription facotrs for ERAD pathway

what does ER-associated Degradation identify

misfolded proteins and dislocates them to the cytosol for proteasome degradation

what happens when Bip diffuses from protein ER Kinase

allow it to dimerize and autophosphorylate

waht are PERK phosphorylates Eukaryotes initiation

inhibit all translation within the cell, reducing the amount of polypeptides entering the ER

a mutation in huntingtin protein

cause excessively long chains of glutamine to accumulate in the ER

what does the accumulation of glutamine trigger

UPR and excessive calcium ion to aggregate in cytosol

what do high levels of calcium ions do

overexcites neurons, resulting in hunington's physiological symptoms