PMID- 11209750
OWN - NLM
STAT- MEDLINE
DCOM- 20010614
LR  - 20131121
IS  - 1431-6730 (Print)
IS  - 1431-6730 (Linking)
VI  - 381
IP  - 12
DP  - 2000 Dec
TI  - Mannosidase action, independent of glucose trimming, is essential for 
      proteasome-mediated degradation of unassembled glycosylated Ig light chains.
PG  - 1155-64
AB  - In order to study the role of N-glycans in the ER-associated degradation of 
      unassembled immunoglobulin light (Ig L) chains, we introduced N-glycan acceptor 
      sites into the variable domain of the murine Ig L chain kappaNS1, which is 
      unfolded in unassembled molecules. We investigated the fate of kappaNS1 
      glycosylated at position 70 (K70) and of a double mutant (kappa18/70) in stably 
      transfected HeLa cells. Degradation of both chains was impaired by lactacystin, a 
      specific inhibitor of the proteasome. The mannosidase inhibitor dMNJ also blocked 
      degradation in a step preceding proteasome action, as did two protein synthesis 
      inhibitors, cycloheximide and puromycin. In contrast, ER glucosidase inhibitors 
      dramatically accelerated the degradation of the chains when added either pre- or 
      posttranslationally. The accelerated degradation was sensitive to lactacystin, 
      dMNJ and cycloheximide, too. None of these drugs, except lactacystin, affected 
      the degradation of unglycosylated kappaNS1 chains. We conclude that ER 
      mannosidases and proteasome activities, but not glucose trimming (and therefore, 
      most likely not the calnexin/calreticulin UDP:glucose glycoprotein glucosyl 
      transferase cycle), are essential for ER-associated degradation (ERAD) of soluble 
      glycoproteins. A role for a short-lived protein, acting before or simultaneously 
      to ER mannosidases, is suggested.
FAU - Chillaron, J
AU  - Chillaron J
AD  - Biochemie-Zentrum Heidelberg (BZH), Germany.
FAU - Adan, C
AU  - Adan C
FAU - Haas, I G
AU  - Haas IG
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Biol Chem
JT  - Biological chemistry
JID - 9700112
RN  - 0 (Immunoglobulin Light Chains)
RN  - 0 (Immunoglobulin Variable Region)
RN  - 0 (Multienzyme Complexes)
RN  - 0 (Plant Proteins)
RN  - 0 (Protein Synthesis Inhibitors)
RN  - EC 3.2.1.- (Glucosidases)
RN  - EC 3.2.1.- (Mannosidases)
RN  - EC 3.4.22.- (Cysteine Endopeptidases)
RN  - EC 3.4.25.1 (Proteasome Endopeptidase Complex)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Animals
MH  - Cysteine Endopeptidases/metabolism/*pharmacology
MH  - Endoplasmic Reticulum/enzymology/metabolism
MH  - Fabaceae/enzymology
MH  - Genes, Immunoglobulin
MH  - Glucose/metabolism
MH  - Glucosidases/antagonists & inhibitors/pharmacology
MH  - Glycosylation
MH  - HeLa Cells
MH  - Humans
MH  - Immunoglobulin Light Chains/drug effects/*metabolism
MH  - Immunoglobulin Variable Region/drug effects/metabolism
MH  - Mannosidases/metabolism/*pharmacology
MH  - Mice
MH  - Multienzyme Complexes/metabolism/*pharmacology
MH  - Mutagenesis, Site-Directed
MH  - Plant Proteins
MH  - Plants, Medicinal
MH  - Proteasome Endopeptidase Complex
MH  - Protein Synthesis Inhibitors/pharmacology
MH  - Transfection
MH  - Translocation, Genetic
EDAT- 2001/02/24 12:00
MHDA- 2001/06/23 10:01
CRDT- 2001/02/24 12:00
PHST- 2001/02/24 12:00 [pubmed]
PHST- 2001/06/23 10:01 [medline]
PHST- 2001/02/24 12:00 [entrez]
AID - 10.1515/BC.2000.143 [doi]
PST - ppublish
SO  - Biol Chem. 2000 Dec;381(12):1155-64. doi: 10.1515/BC.2000.143.