Linked Life Data

10329729

Source:http://linkedlifedata.com/resource/pubmed/id/10329729

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1999-7-9
pubmed:abstractText
Glycosylphosphatidylinositols (GPIs) are synthesized in the endoplasmic reticulum (ER) via the sequential addition of monosaccharides, fatty acid, and phosphoethanolamine(s) to phosphatidylinositol (PI). While attempting to establish a mammalian cell-free system for GPI biosynthesis, we found that the assembly of mannosylated GPI species was impaired when purified ER preparations were substituted for unfractionated cell lysates as the enzyme source. To explore this problem we analyzed the distribution of the various GPI biosynthetic reactions in subcellular fractions prepared from homogenates of mammalian cells. The results indicate the following: (i) the initial reaction of GPI assembly, i.e. the transfer of GlcNAc to PI to form GlcNAc-PI, is uniformly distributed in the ER; (ii) the second step of the pathway, i.e. de-N-acetylation of GlcNAc-PI to yield GlcN-PI, is largely confined to a subcompartment of the ER that appears to be associated with mitochondria; (iii) the mitochondria-associated ER subcompartment is enriched in enzymatic activities involved in the conversion of GlcN-PI to H5 (a singly mannosylated GPI structure containing one phosphoethanolamine side chain; and (iv) the mitochondria-associated ER subcompartment, unlike bulk ER, is capable of the de novo synthesis of H5 from UDP-GlcNAc and PI. The confinement of these GPI biosynthetic reactions to a domain of the ER provides another example of the compositional and functional heterogeneity of the ER. The implications of these findings for GPI assembly are discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
274
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15203-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Segregation of glycosylphosphatidylinositol biosynthetic reactions in a subcompartment of the endoplasmic reticulum.
pubmed:affiliation
Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1569, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't