Format

Send to

Choose Destination
See comment in PubMed Commons below
Atherosclerosis. 2011 Sep;218(1):134-43. doi: 10.1016/j.atherosclerosis.2011.05.008. Epub 2011 May 18.

Identification of a gene variant in the master regulator of lipid metabolism SREBP-1 in a family with a novel form of severe combined hypolipidemia.

Author information

1
Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, Aufm Hennekamp 65, 40225 Duesseldorf, Germany.

Abstract

OBJECTIVE:

Alterations of lipid metabolism play a pivotal role in the development of atherosclerosis and its complications, today's major mortality risks. The predominant regulators controlling cholesterol- and fatty acids synthesis in liver are the sterol regulatory element-binding proteins (SREBPs), a family of transcription factors that were formerly identified as cholesterol sensor for LDLR gene expression. Variation of gene structure in these genes might therefore indicate a predisposition to develop complications like myocardial infarction and stroke.

METHODS:

We investigated 190 unrelated German subjects, including 69 subjects with LDL-cholesterol <55mg/dl, for mutations in SREBP genes SREBF-1 and SREBF-2 by direct sequencing. The impact on SREBP functionality was analyzed by protein biochemical analyses, promoter reporter gene assays and gene expression studies.

RESULTS:

A missense mutation in SREBF-1 (c.332 C>T; P111L) was identified in a subject with LDL-cholesterol <5mg/dl. Examination of the subject's family confirmed the mutation in two of three siblings. Detailed clinical evaluation of these subjects disclose a novel form of primary combined hypolipidemia only in SREBP-1a P111L carriers, characterized by low levels of apoB and apoA1, low triglyceride, LDL-cholesterol and HDL-cholesterol levels. Functional analyses indicated that the mutation abolishes phosphorylation of SREBP-1. As a consequence transcriptional activation of classical target genes, i.e. LDLR, HMG-CoAR, FAS, ABCA1, but also MTTP, was dramatically reduced.

CONCLUSIONS:

Phosphorylation of SREBP-1, the master regulator of genes for central rate limiting enzymes of cholesterol and lipid metabolism, appears to be a biological principle with clinical implications.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center