The non-protein amino acid BMAA is misincorporated into human proteins in place of L-serine causing protein misfolding and aggregation

PLoS One. 2013 Sep 25;8(9):e75376. doi: 10.1371/journal.pone.0075376. eCollection 2013.

Abstract

Mechanisms of protein misfolding are of increasing interest in the aetiology of neurodegenerative diseases characterized by protein aggregation and tangles including Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), Lewy Body Dementia (LBD), and Progressive Supranuclear Palsy (PSP). Some forms of neurodegenerative illness are associated with mutations in genes which control assembly of disease related proteins. For example, the mouse sticky mutation sti, which results in undetected mischarging of tRNA(Ala) with serine resulting in the substitution of serine for alanine in proteins causes cerebellar Purkinje cell loss and ataxia in laboratory animals. Replacement of serine 422 with glutamic acid in tau increases the propensity of tau aggregation associated with neurodegeneration. However, the possibility that environmental factors can trigger abnormal folding in proteins remains relatively unexplored. We here report that a non-protein amino acid, β-N-methylamino-L-alanine (BMAA), can be misincorporated in place of L-serine into human proteins. We also report that this misincorporation can be inhibited by L-serine. Misincorporation of BMAA into human neuroproteins may shed light on putative associations between human exposure to BMAA produced by cyanobacteria and an increased incidence of ALS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids, Diamino / analysis*
  • Amino Acids, Diamino / metabolism
  • Cell Culture Techniques
  • Cell Line
  • Chromatography, High Pressure Liquid
  • Cyanobacteria / chemistry*
  • Cyanobacteria Toxins
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • L-Lactate Dehydrogenase / metabolism
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / chemistry*
  • Proteostasis Deficiencies / genetics*
  • Tandem Mass Spectrometry
  • Tritium

Substances

  • Amino Acids, Diamino
  • Cyanobacteria Toxins
  • Nerve Tissue Proteins
  • Tritium
  • beta-N-methylamino-L-alanine
  • L-Lactate Dehydrogenase

Grants and funding

This work was funded by D. M. Kinney and the Deerbrook Charitable Trust (Institute for Ethnomedicine, Wyoming) and University of Technology, New South Wales. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.