Linked Life Data

9328280

Source:http://linkedlifedata.com/resource/pubmed/id/9328280

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-10-29
pubmed:abstractText
The retinal pigment epithelium (RPE)-specific protein RPE65 is the major protein of the RPE microsomal membrane fraction. Though RPE65 lacks transmembrane domains or signal peptide, detergents are required for its maximally effective solubilization in isotonic buffers. However, in 0.75-1.0 M KCl, RPE65 is as soluble without detergent, indicating a peripheral membrane association. We wished to understand why this non-membrane-inserted protein was so closely associated with RPE microsomal membranes. To explore the possible involvement of interactions with phospholipids, an isotonic salt-soluble extract of RPE was incubated with phosphatidylcholine (PC)/phosphatidylserine (PS)/phosphatidylinositol liposomes and centrifuged to sediment the liposomes. RPE65 cosedimented with the liposome pellet. RPE65 also cosedimented with synthetic dipalmitoyl-, 1-palmitoyl, 2-docosahexaenoyl-PC or dipalmitoyl-PS liposomes. Incubation with 1 mM Ca2+ or 1 mM EGTA had no effect, indicating a Ca2+-independent association. A spectrophotometric assay showed that this interaction of RPE65 with phospholipid vesicles resulted in increased light scattering, consistent with phospholipid vesicle aggregation. Resonance energy transfer experiments showed that any putative aggregation occurred without subsequent vesicle fusion. This PC affinity was further confirmed by incubation of RPE extract with dimyristoyl-PC-immobilized artificial membrane (IAM.PC) matrix. The RPE65 selectively bound and was elutable with 2% detergent. This RPE65-phospholipid liposome association may explain the solubilization characteristics of RPE65 and may be related to the function of RPE65 and to its physical association with the RPE smooth endoplasmic reticulum.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
346
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21-7
pubmed:dateRevised
2006-11-20
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
RPE65, the major retinal pigment epithelium microsomal membrane protein, associates with phospholipid liposomes.
pubmed:affiliation
Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article