Get access
Advertisement

The UBIAD1 Prenyltransferase Links Menaquione-4 Synthesis to Cholesterol Metabolic Enzymes

Authors

Errata

This article is corrected by:

  1. Errata: The UBIAD1 Prenyltransferase Links Menaquinone-4 Synthesis to Cholesterol Metabolic Enzymes Volume 34, Issue 7, 1046, Article first published online: 30 April 2013

  • Contract grant sponsors: Midwest Eye Banks and Research to Prevent Blindness [to J.S.W.]; National Cancer Institute, National Institutes of Health (HHSN261200800001E); National Cancer Institute Intramural Research Program (to M.L.N., B.N.K., and M.D.]

  • Communicated by Peter Oefner

Correspondence to: Michael L. Nickerson, 1050 Boyles Street, Building 560, Room 21-21, National Cancer Institute, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA. E-mail: nickersonml@mail.nih.gov

ABSTRACT

Schnyder corneal dystrophy (SCD) is an autosomal dominant disease characterized by germline variants in UBIAD1 introducing missense alterations leading to deposition of cholesterol in the cornea, progressive opacification, and loss of visual acuity. UBIAD1 was recently shown to synthesize menaquinone-4 (MK-4, vitamin K2), but causal mechanisms of SCD are unknown. We report a novel c.864G>A UBIAD1 mutation altering glycine 177 to glutamic acid (p.G177E) in six SCD families, including four families from Finland who share a likely founder mutation. We observed reduced MK-4 synthesis by UBIAD1 altered by SCD mutations p.N102S, p.G177R/E, and p.D112N, and molecular models showed p.G177-mutant UBIAD1 disrupted transmembrane helices and active site residues. We show UBIAD1 interacts with HMGCR and SOAT1, enzymes catalyzing cholesterol synthesis and storage, respectively, using yeast two-hybrid screening and immunoprecipitation. Docking simulations indicate cholesterol binds to UBIAD1 in the substrate-binding cleft and substrate-binding overlaps with GGPP binding, an MK-4 substrate, suggesting potential competition between these metabolites. Impaired MK-4 synthesis is a biochemical defect identified in SCD suggesting UBIAD1 links vitamin K and cholesterol metabolism through physical contact between enzymes and metabolites. Our data suggest a role for endogenous MK-4 in maintaining cornea health and visual acuity.

Get access to the full text of this article

Ancillary