High mobility group protein-B1 interacts with sterol regulatory element-binding proteins to enhance their DNA binding.
Sterol regulatory element-binding proteins (SREBPs) are transcription factors that are predominately involved in the regulation of lipogenic and cholesterogenic enzyme gene expression. To identify unknown proteins that interact with SREBP, we screened nuclear extract proteins with 35S-labeled SREBP-1 bait in Far Western blotting analysis. Using this approach, high mobility group protein-B1 (HMGB1), a chromosomal protein, was identified as a novel SREBP interacting protein. In vitro glutathione S-transferase pull-down and in vivo coimmunoprecipitation studies confirmed an interaction between HMGB1 and both SREBP-1 and -2. The protein-protein interaction was mediated through the helix-loop-helix domain of SREBP-1, residues 309-344, and the A box of HMGB1. Furthermore, an electrophoretic mobility shift assay demonstrated that HMGB1 enhances SREBPs binding to their cognate DNA sequences. Moreover, luciferase reporter analyses, including RNA interference technique showed that HMGB1 potentiates the transcriptional activities of SREBP in cultured cells. These findings raise the intriguing possibility that HMGB1 is potentially involved in the regulation of lipogenic and cholesterogenic gene transcription.
Najima
Yuho
Y
Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan.
Yahagi
Naoya
N
Takeuchi
Yoshinori
Y
Matsuzaka
Takashi
T
Sekiya
Motohiro
M
Nakagawa
Yoshimi
Y
Amemiya-Kudo
Michiyo
M
Okazaki
Hiroaki
H
Okazaki
Sachiko
S
Tamura
Yoshiaki
Y
Iizuka
Yoko
Y
Ohashi
Ken
K
Harada
Kenji
K
Gotoda
Takanari
T
Nagai
Ryozo
R
Kadowaki
Takashi
T
Ishibashi
Shun
S
Yamada
Nobuhiro
N
Osuga
Jun-ichi
J
Shimano
Hitoshi
H
D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000378:metabolism; D024243:HMGB1 Protein / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation; D008099:Liver / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008957:Models, Genetic; D009841:Oligonucleotides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D011994:Recombinant Proteins / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D024243:HMGB1 Protein; D009841:Oligonucleotides; D010455:Peptides; D011994:Recombinant Proteins; C497387:SREBF1 protein, human; C497390:SREBF2 protein, human; C497388:Srebf1 protein, mouse; C497391:Srebf2 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors; D004247:DNA; D008156:Luciferases; D005982:Glutathione Transferase