Linked Life Data

20065073

Source:http://linkedlifedata.com/resource/pubmed/id/20065073

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2010-4-8
pubmed:abstractText
Glycoprotein folding and degradation in the endoplasmic reticulum (ER) is mediated by the ER quality control system. Mannose trimming plays an important role by forming specific N-glycans that permit the recognition and sorting of terminally misfolded conformers for ERAD (ER-associated degradation). The EDEM (ER degradation enhancing alpha-mannosidase-like protein) subgroup of proteins belonging to the Class I alpha1,2-mannosidase family (glycosylhydrolase family 47) has been shown to enhance ERAD. We recently reported that overexpression of EDEM3 enhances glycoprotein ERAD with a concomitant increase in mannose-trimming activity in vivo. Herein, we report that overexpression of EDEM1 produces Glc(1)Man(8)GlcNAc(2) isomer C on terminally misfolded null Hong Kong alpha1-antitrypsin (NHK) in vivo. Levels of this isomer increased throughout the chase period and comprised approximately 10% of the [(3)H]mannose-labeled N-glycans on NHK after a 3-h chase. Furthermore, overexpression of EDEM1 E220Q containing a mutation in a conserved catalytic residue essential for alpha1,2-mannosidase activity did not yield detectable levels of Glc(1)Man(8)GlcNAc(2) isomer C. Yet, the same extent of NHK ERAD-enhancement was observed in both EDEM1 and EDEM1 E220Q overexpressing cells. This can be attributed to both wild-type and mutant EDEM1 inhibiting aberrant NHK dimer formation. We further analyzed the N-glycan profile of total cellular glycoproteins from HepG2 cells stably overexpressing EDEM1 and found that the relative amount of Man(7)GlcNAc(2) isomer A, which lacks the terminal B and C branch mannoses, was increased compared to parental HepG2 cells. Based on this observation, we conclude that EDEM1 activity trims mannose from the C branch of N-glycans in vivo.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1460-2423
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
567-75
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
EDEM1 accelerates the trimming of alpha1,2-linked mannose on the C branch of N-glycans.
pubmed:affiliation
Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8397, Japan. nobukoh@frontier.kyoto-u.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't