Characterization of essential domains in HSD17B13 for cellular localization and enzymatic activity

J Lipid Res. 2020 Nov;61(11):1400-1409. doi: 10.1194/jlr.RA120000907. Epub 2020 Sep 24.

Abstract

Human genetic studies recently identified an association of SNPs in the 17-β hydroxysteroid dehydrogenase 13 (HSD17B13) gene with alcoholic and nonalcoholic fatty liver disease development. Mutant HSD17B13 variants devoid of enzymatic function have been demonstrated to be protective from cirrhosis and liver cancer, supporting the development of HSD17B13 as a promising therapeutic target. Previous studies have demonstrated that HSD17B13 is a lipid droplet (LD)-associated protein. However, the critical domains that drive LD targeting or determine the enzymatic activity have yet to be defined. Here we used mutagenesis to generate multiple truncated and point-mutated proteins and were able to demonstrate in vitro that the N-terminal hydrophobic domain, PAT-like domain, and a putative α-helix/β-sheet/α-helix domain in HSD17B13 are all critical for LD targeting. Similarly, we characterized the predicted catalytic, substrate-binding, and homodimer interaction sites and found them to be essential for the enzymatic activity of HSD17B13, in addition to our previous identification of amino acid P260 and cofactor binding site. In conclusion, we identified critical domains and amino acid sites that are essential for the LD localization and protein function of HSD17B13, which may facilitate understanding of its function and targeting of this protein to treat chronic liver diseases.

Keywords: alcoholic liver disease; enzyme regulation; lipid droplets; nonalcoholic fatty liver disease; protein structure; retinoids.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • 17-Hydroxysteroid Dehydrogenases / analysis
  • 17-Hydroxysteroid Dehydrogenases / antagonists & inhibitors
  • 17-Hydroxysteroid Dehydrogenases / metabolism*
  • Cells, Cultured
  • Chronic Disease
  • Humans
  • Liver Diseases / drug therapy*
  • Liver Diseases / metabolism
  • Liver Diseases / pathology
  • Small Molecule Libraries / pharmacology

Substances

  • Small Molecule Libraries
  • 17-Hydroxysteroid Dehydrogenases
  • HSD17B13 protein, human