BRCA1 affects lipid synthesis through its interaction with acetyl-CoA carboxylase.
Germ line alterations in BRCA1 (breast cancer susceptibility gene 1) are associated with an increased susceptibility to breast and ovarian cancer. BRCA1 acts as a scaffold protein implicated in multiple cellular functions, such as transcription, DNA repair, and ubiquitination. However, the molecular mechanisms responsible for tumorigenesis are not yet fully understood. We have recently demonstrated that BRCA1 interacts in vivo with acetyl coenzyme A carboxylase alpha (ACCA) through its tandem of BRCA1 C terminus (BRCT) domains. To understand the biological function of the BRCA1.ACCA complex, we sought to determine whether BRCA1 is a regulator of lipogenesis through its interaction with ACCA. We showed here that RNA inhibition-mediated down-regulation of BRCA1 expression induced a marked increase in the fatty acid synthesis. We then delineated the biochemical characteristics of the complex and found that BRCA1 interacts solely with the phosphorylated and inactive form of ACCA (P-ACCA). Finally, we demonstrated that BRCA1 affects lipid synthesis by preventing P-ACCA dephosphorylation. These results suggest that BRCA1 affects lipogenesis through binding to P-ACCA, providing a new mechanism by which BRCA1 may exert a tumor suppressor function.
Moreau
Karen
K
CNRS UMR 5201, Laboratoire de Génétique Moléculaire, Signalisation et Cancer, Faculté deMédecine Rockefeller, 69373 Lyon cedex 08, France.
Dizin
Eva
E
Ray
Hind
H
Luquain
Céline
C
Lefai
Etienne
E
Foufelle
Fabienne
F
Billaud
Marc
M
Lenoir
Gilbert M
GM
Venezia
Nicole Dalla
ND
D000103:Acetyl-CoA Carboxylase / Q000737:chemistry* / Q000378:metabolism; D019313:BRCA1 Protein / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D004260:DNA Repair; D015536:Down-Regulation; D005227:Fatty Acids / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008055:Lipids / Q000737:chemistry*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection; D025801:Ubiquitin / Q000737:chemistry; D015854:Up-Regulation
D019313:BRCA1 Protein; D005227:Fatty Acids; D008055:Lipids; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; D012313:RNA; D005982:Glutathione Transferase; D000103:Acetyl-CoA Carboxylase