Linked Life Data

12551903

Source:http://linkedlifedata.com/resource/pubmed/id/12551903

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2003-4-7
pubmed:abstractText
Familial hypobetalipoproteinemia (FHBL), an autosomal co-dominant disorder, is associated with reduced plasma concentrations (<5th percentile for age and sex) of apolipoprotein (apo) B and beta-migrating lipoproteins. To date, only mutations in APOB encoding prematurely truncated apoB have been found in FHBL. We discovered a novel APOB gene mutation, namely R463W, in an extended Christian Lebanese FHBL kindred. Heterozygotes for R463W had the typical FHBL phenotype, whereas homozygotes had barely detectable apoB-100. The effect of the R463W mutation on apoB secretion was examined using transfected McA-RH7777 cells that expressed one of two recombinant human apoBs, namely B48 and B17. In both cases, the mutant proteins (B48RW and B17RW) were retained within the endoplasmic reticulum and were secreted poorly compared with their wild-type counterparts. Pulse-chase analysis showed that secretion efficiencies of B48RW and B17RW were, respectively, 45 and 40% lower than those of the wild-types. Substitution of Arg(463) with Ala in apoB-17 (B17RA) decreased secretion efficiency by approximately 50%, but substitution with Lys (B17RK) had no effect on secretion, indicating that the positive charge was important. Molecular modeling of apoB predicted that Arg(463) was in close proximity to Glu(756) and Asp(456). Substitution of Glu(756) with Gln (B17EQ) had no effect on secretion, but substitution of Asp(456) with Asn (B17DN) decreased secretion to the same extent as B17RW. In co-transfection experiments, the mutant B17RW showed increased binding to microsomal triglyceride transfer protein as compared with wild-type B17. Thus, the naturally occurring R463W mutant reveals a key local domain governing assembly and secretion of apoB-containing lipoproteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13442-52
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
A novel nontruncating APOB gene mutation, R463W, causes familial hypobetalipoproteinemia.
pubmed:affiliation
Department of Core Clinical Pathology and Biochemistry, Royal Perth Hospital and Department of Pathology, University of Western Australia, Perth WA 6847, Western Australia, Australia. john.burnett@health.wa.gov.au
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't