Abstract
HNF4α (hepatocyte nuclear factor 4α) is one of the master regulators of pancreatic β-cell development and function, and mutations in the HNF4α gene are well-known monogenic causes of diabetes. As a member of the nuclear receptor family, HNF4α exerts its gene regulatory function through various molecular interactions; however, there is a paucity of knowledge of the different functional complexes in which HNF4α participates. Here, to find HNF4α-binding proteins in pancreatic β-cells, we used yeast two-hybrid screening, a mammalian two-hybrid assay, and glutathione S-transferase pulldown approaches, which identified EBP1 (ErbB3-binding protein 1) as a factor that binds HNF4α in a LXXLL motif-mediated manner. In theβ-cells, EBP1 suppressed the expression of HNF4α target genes that are implicated in insulin secretion, which is impaired in HNF4α mutation-driven diabetes. The crystal structure of the HNF4α ligand-binding domain in complex with a peptide harboring the EBP1 LXXLL motif at 3.15Å resolution hinted at the molecular basis of the repression. The details of the structure suggested that EBP1's LXXLL motif competes with HNF4α coactivators for the same binding pocket and thereby prevents recruitment of additional transcriptional coactivators. These findings provide further evidence that EBP1 plays multiple cellular roles and is involved in nuclear receptor-mediated gene regulation. Selective disruption of the HNF4α-EBP1 interaction or tissue-specific EBP1 inactivation can enhance HNF4α activities and thereby improve insulin secretion in β-cells, potentially representing a new strategy for managing diabetes and related metabolic disorders.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 13983-13994 |
| Number of pages | 12 |
| Journal | Journal of Biological Chemistry |
| Volume | 294 |
| Issue number | 38 |
| DOIs | |
| State | Published - Sep 20 2019 |
Bibliographical note
Funding Information:This work was supported by American Diabetes Association Grant 7-08-CD-03; Commonwealth of Kentucky Diabetes Research Trust Fund Grant KDRPP09-09; Brain Pool Program Grant 2018H1D3A2000849 funded by the Ministry of Science and ICT through the National Research Foundation of Korea (to Y.-I. C.); Korea Health Technology R&D Project Grant HI16C1501 through the Korea Health Industry Development Institute funded by the Ministry of Health & Welfare, Republic of Korea; and the Bio & Medical Technology Development Program of the National Research Foundation funded by Korean Government Grant NRF-2016M3A9B6902872 (to I.-K. L.). This study was also supported in part by the Theodore W. Batterman Family Foundation and the Advancing a Healthier Wisconsin Endowment to the Precision Medicine Simulation Unit of the Genomic Sciences and Precision Medicine Center at the Medical College of Wisconsin. The authors declare that they have no conflicts of interest with the contents of this article.
Funding Information:
This work was supported by American Diabetes Association Grant 7-08-CD-03; Commonwealth of Kentucky Diabetes Research Trust Fund Grant KDR-PP09-09; Brain Pool Program Grant 2018H1D3A2000849 funded by the Ministry of Science and ICT through the National Research Foundation of Korea (to Y.-I. C.); Korea Health Technology R&D Project Grant HI16C1501 through the Korea Health Industry Development Institute funded by the Ministry of Health & Welfare, Republic of Korea; and the Bio & Medical Technology Development Program of the National Research Foundation funded by Korean Government Grant NRF-2016M3A9B6902872 (to I.-K. L.). This study was also supported in part by the Theodore W. Batterman Fam-ily Foundation and the Advancing a Healthier Wisconsin Endowment to the Precision Medicine Simulation Unit of the Genomic Sciences and Pre-cision Medicine Center at the Medical College of Wisconsin. The authors declare that they have no conflicts of interest with the contents of this article.
Publisher Copyright:
© 2019 Han et al.
