Structural properties of the HNF-1A transactivation domain

Laura Kind; Mark Driver; Arne Raasakka; Patrick R Onck; Pål Rasmus Njølstad; Thomas Arnesen; Petri Kursula

doi:10.3389/fmolb.2023.1249939

Structural properties of the HNF-1A transactivation domain

Front Mol Biosci. 2023 Oct 16:10:1249939. doi: 10.3389/fmolb.2023.1249939. eCollection 2023.

Authors

Laura Kind¹, Mark Driver², Arne Raasakka¹, Patrick R Onck², Pål Rasmus Njølstad^{3

4}, Thomas Arnesen^{1

5}, Petri Kursula^{1

6}

Affiliations

¹ Department of Biomedicine, University of Bergen, Bergen, Norway.
² Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands.
³ Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway.
⁴ Section of Endocrinology and Metabolism, Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway.
⁵ Department of Surgery, Haukeland University Hospital, Bergen, Norway.
⁶ Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland.

Abstract

Hepatocyte nuclear factor 1α (HNF-1A) is a transcription factor with important gene regulatory roles in pancreatic β-cells. HNF1A gene variants are associated with a monogenic form of diabetes (HNF1A-MODY) or an increased risk for type 2 diabetes. While several pancreatic target genes of HNF-1A have been described, a lack of knowledge regarding the structure-function relationships in HNF-1A prohibits a detailed understanding of HNF-1A-mediated gene transcription, which is important for precision medicine and improved patient care. Therefore, we aimed to characterize the understudied transactivation domain (TAD) of HNF-1A in vitro. We present a bioinformatic approach to dissect the TAD sequence, analyzing protein structure, sequence composition, sequence conservation, and the existence of protein interaction motifs. Moreover, we developed the first protocol for the recombinant expression and purification of the HNF-1A TAD. Small-angle X-ray scattering and synchrotron radiation circular dichroism suggested a disordered conformation for the TAD. Furthermore, we present functional data on HNF-1A undergoing liquid-liquid phase separation, which is in line with in silico predictions and may be of biological relevance for gene transcriptional processes in pancreatic β-cells.

Keywords: HNF-1A; MODY; diabetes; intrinsically disordered protein; liquid-liquid phase separation; short linear motif; transcription factor; β-cell.

Grants and funding

We thank BioCat—The National graduate school in biocatalysis—for financial support connected to beamtime travel. We acknowledge the use of the Core Facility for Biophysics, Structural Biology, and Screening (BiSS) at the University of Bergen, which has received infrastructure funding from the Research Council of Norway (RCN) through NORCRYST (grant number 245828) and NOR–OPENSCREEN (grant number 245922). This work was funded with a PhD fellowship by the Medical Faculty, University of Bergen, UiB, Norway (to LK) and by project grants awarded by the UiB Meltzer foundation (to LK). We thank the oLife COFUND project for funding (to MD). The COFUND project oLife has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 847675. This work made use of the Dutch national e-infrastructure with the support of the SURF Cooperative using grant no. EINF-3233.