Quality control in ER

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Quality control in ER????
N-X-S/T?N??????N-??????????ER????????????folding,
????targeting(ER??Golgi????)???????????
??????O-????????Golgi????????????solubility???,???
??????????????????????????????????????????
Dolichol(??,?????????)?????????????Flip???????4Man
, 3Glc????? (Glc)3(Man)9(GlcNAc)2????Nascent
polypeptide chain???(?????)
????
Oligosaccharyl-transferase (OST)
???3Glc???????? I and II (GI and GII) ???????????
GII ? UDP-Glc glucosyltransferase (UGGT)
???????(chaperone?????????) ???folding
???????????????????a-1,2-mannnosidase????(Man)8(Gl
cNAc)2??????????UGGT??????????conformation????????
??COP II????????Golgi????????????????????Glc(Man)8
(GlcNAc)2????????????
http//jcggdb.jp/doc/Disp.action?projectId3langT
ype1dMSId118pageNo1
calreticulin (CRT a soluble homologue of CNX)
ERAD (ER-associated degradation)??
ER????????folding???????folding???????????????????
???? Calnexin/Calreticulin?Glc(Man)9(GlcNAc)2????
???????Chaperone????ER?????? EDEM (ER
degra-dation enhancing mannosidase-like protein)
?Glc-(Man)8(GlcNAc)2????Translocon?????Retrotransl
ocation???????????????Fbs1 (E3) ??????????Peptide
N-glycanase (PNGase) ??????????Proteasome?19S cap
(???????)? ?????????????????????
????????????????????????(ERAD)????????ER?????????
???????(ER stress)?ER?????????????????????????????
???ER chaperone???????????????????????????????????
?????????chaperone???????????(unfolded protein
response UPR)?????ATF6(??)??chaperone????????????
Golgi??????????Golgi?????????????RIP (Regulated
intramembrane proteolysis)?????????(Alzhei-mer????
???????b???g-secre-tase?????)?????????????????????
????????????????????????????????????????????(??Ask
1? JSK ??????????)?
Golgi
or Derlin channel
???Golgi??????? ?????UDP-, GDP-,
CMP(CDP????????)-???????????????Man??????????????
?Lysosome targeting signal????
CMP???????????????????Isoform?????
??? 84 18-29, 2012
???N-linked glycan??????????(a-n)?glycoside?????
??????Unfolding, MHC Class I?????
1, 3. a-2-mannnosidase 2, 4. N-Acetylglucosamine
transferase I 5. Fucosyl transferase 6.Galac
tosyl transferase 7. Sialyl transferase
Molecular Cell 10 983-994, 2002
ER chaperone???????? BiP (Grp78, Hsp70), Grp94
(Hsp90), Grp170 (Hsp70), PDI (Protein disulfide
isomerase??), ERp72 (thiol oxidoreductase),
Calreticulin ????????? Calnexin/Calreticulin
with ERp57, ?????????? PPI (Peptidyl prolyl
cis/trans isomerase), many other redox
proteins Grp glucose regulated proteins
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• http//www.chem.sci.osaka-u.ac.jp/lab/kajihara/bac
  kground.html