Linked Life Data

15835887

Source:http://linkedlifedata.com/resource/pubmed/id/15835887

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2005-4-19
pubmed:abstractText
Oligosaccharyltransferase (OST) catalyzes the cotranslational transfer of high-mannose sugars to nascent polypeptides during N-linked glycosylation in the rough endoplasmic reticulum lumen. Nine OST subunits have been identified in yeast. However, the composition and organization of mammalian OST remain unclear. Using two-dimensional Blue Native polyacrylamide gel electrophoresis/sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry, we now demonstrate that mammalian OST can be isolated from solubilized, actively engaged ribosomes as multiple distinct protein complexes that range in size from approximately 500 to 700 kDa. These complexes exhibit different ribosome affinities and subunit compositions. The major complex, OSTC(I), had an apparent size of approximately 500 kDa and was readily released from ribosome translocon complexes after puromycin treatment under physiological salt conditions. Two additional complexes were released only after treatment with high salt: OSTC(II) ( approximately 600 kDa) and OSTC(III) ( approximately 700 kDa). Both remained stably associated with heterotrimeric Sec61alphabetagamma, while OSTC(III) also contained the tetrameric TRAP complex. All known mammalian OST subunits (STT3-A, ribophorin I, ribophorin II, OST48, and DAD1) were present in all complexes. In addition, two previously uncharacterized proteins were also copurified with OST. Mass spectrometry identified a 17 kDa protein as DC2 which is weakly homologous to the C-terminal half of yeast Ost3p and Ost6p. The second protein (14 kDa) was tentatively identified as keratinocyte-associated protein 2 (KCP2) and has no previously known function. Our results identify two potential new subunits of mammalian OST and demonstrate a remarkable heterogeneity in OST composition that may reflect a means for controlling nascent chain glycosylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5982-92
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15835887-Acid Phosphatase, pubmed-meshheading:15835887-Amino Acid Sequence, pubmed-meshheading:15835887-Animals, pubmed-meshheading:15835887-Dogs, pubmed-meshheading:15835887-Electrophoresis, Gel, Two-Dimensional, pubmed-meshheading:15835887-Endoplasmic Reticulum, pubmed-meshheading:15835887-Hexosyltransferases, pubmed-meshheading:15835887-Humans, pubmed-meshheading:15835887-Isoenzymes, pubmed-meshheading:15835887-Mass Spectrometry, pubmed-meshheading:15835887-Membrane Proteins, pubmed-meshheading:15835887-Molecular Sequence Data, pubmed-meshheading:15835887-Molecular Weight, pubmed-meshheading:15835887-Multiprotein Complexes, pubmed-meshheading:15835887-Pancreas, pubmed-meshheading:15835887-Protein Subunits, pubmed-meshheading:15835887-Proteomics, pubmed-meshheading:15835887-Puromycin, pubmed-meshheading:15835887-Salts, pubmed-meshheading:15835887-Sequence Homology, Amino Acid
pubmed:year
2005
pubmed:articleTitle
Proteomic analysis of mammalian oligosaccharyltransferase reveals multiple subcomplexes that contain Sec61, TRAP, and two potential new subunits.
pubmed:affiliation
Division of Molecular Medicine, Oregon Health and Sciences University, 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't