Role of UDP-N-acetylglucosamine2-epimerase/N-acetylmannosamine kinase (GNE) in β1-integrin-mediated cell adhesion

Mol Neurobiol. 2014 Oct;50(2):257-73. doi: 10.1007/s12035-013-8604-6. Epub 2014 Jan 29.

Abstract

Hereditary inclusion body myopathy (GNE myopathy) is a neuromuscular disorder due to mutation in key sialic acid biosynthetic enzyme, GNE. The pathomechanism of the disease is poorly understood as GNE is involved in other cellular functions beside sialic acid synthesis. In the present study, a HEK293 cell-based model system has been established where GNE is either knocked down or over-expressed along with pathologically relevant GNE mutants (D176V and V572L). The subcellular distribution of recombinant GNE and its mutant showed differential localization in the cell. The effect of mutation on GNE function was investigated by studying hyposialylation of cell membrane receptor, β1-integrin. Hyposialylated β1-integrin localized to internal vesicles that was restored upon supplementation with sialic acid. Fibronectin stimulation caused migration of hyposialylated β1-integrin to the cell membrane and co-localization with focal adhesion kinase (FAK) leading to increased focal adhesion formation. This further activated FAK and Src, downstream signaling molecules and led to increased cell adhesion. This is the first report to show that mutation in GNE affects β1-integrin-mediated cell adhesion process in GNE mutant cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Epimerases / genetics
  • Carbohydrate Epimerases / metabolism
  • Cell Adhesion / genetics
  • Cell Adhesion / physiology
  • Cell Membrane / metabolism
  • Cells, Cultured
  • HEK293 Cells
  • Humans
  • Integrin beta1 / metabolism*
  • Muscular Diseases / genetics
  • Muscular Diseases / metabolism
  • Mutation / genetics*
  • N-Acetylneuraminic Acid / genetics
  • N-Acetylneuraminic Acid / metabolism*

Substances

  • Integrin beta1
  • Carbohydrate Epimerases
  • UDP acetylglucosamine-2-epimerase
  • N-Acetylneuraminic Acid