| Abstract | Recent studies have demonstrated that aldo-keto reductase family 1 B10 (AKR1B10), a novel protein overexpressed in human hepatocellular carcinoma and non-small cell lung carcinoma, may facilitate cancer cell growth by detoxifying intracellular reactive carbonyls. This study presents a novel function of AKR1B10 in tumorigenic mammary epithelial cells (RAO-3), regulating fatty acid synthesis. In RAO-3 cells, Sephacryl-S 300 gel filtration and DEAE-Sepharose ion exchange chromatography demonstrated that AKR1B10 exists in two distinct forms, monomers (approximately 40 kDa) bound to DEAE-Sepharose column and protein complexes (approximately 300 kDa) remaining in flow-through. Co-immunoprecipitation with AKR1B10 antibody and protein mass spectrometry analysis identified that AKR1B10 associates with acetyl-CoA carboxylase-alpha (ACCA), a rate-limiting enzyme of de novo fatty acid synthesis. This association between AKR1B10 and ACCA proteins was further confirmed by co-immunoprecipitation with ACCA antibody and pulldown assays with recombinant AKR1B10 protein. Intracellular fluorescent studies showed that AKR1B10 and ACCA proteins co-localize in the cytoplasm of RAO-3 cells. More interestingly, small interfering RNA-mediated AKR1B10 knock down increased ACCA degradation through ubiquitination-proteasome pathway and resulted in >50% decrease of fatty acid synthesis in RAO-3 cells. These data suggest that AKR1B10 is a novel regulator of the biosynthesis of fatty acid, an essential component of the cell membrane, in breast cancer cells. |
| Authors | Jun Ma, Ruilan Yan, Xuyu Zu, Ji-Ming Cheng, Krishna Rao, Duan-Fang Liao, Deliang Cao
(Affiliation: Department of Medical Microbiology, Immunology, and Cell Biology, SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, Springfield, Illinois 62702, USA.)
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| Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 283
Issue 6
Pg. 3418-23
(Feb 8 2008)
ISSN: 0021-9258 United States |
| PMID | 18056116
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- Fatty Acids
- RNA, Small Interfering
- Recombinant Proteins
- Ubiquitin
- AKR1B10 protein, human
- Aldehyde Reductase
- Proteasome Endopeptidase Complex
- Acetyl-CoA Carboxylase
|
| Topics |
- Acetyl-CoA Carboxylase
(chemistry, metabolism)
- Aldehyde Reductase
(genetics, physiology)
- Breast Neoplasms
(metabolism)
- Cell Line, Tumor
- Cell Membrane
(metabolism)
- Cytoplasm
(metabolism)
- Fatty Acids
(metabolism)
- Gene Expression Regulation, Neoplastic
- Gene Silencing
- Humans
- Proteasome Endopeptidase Complex
(metabolism)
- RNA, Small Interfering
(metabolism)
- Recombinant Proteins
(chemistry)
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Ubiquitin
(metabolism)
|
