The autolysis of human HtrA1 is governed by the redox state of its N-terminal domain

Biochemistry. 2014 Jun 17;53(23):3851-7. doi: 10.1021/bi401633w. Epub 2014 Jun 6.

Abstract

Human HtrA1 (high-temperature requirement protein A1) belongs to a conserved family of serine proteases involved in protein quality control and cell fate. The homotrimeric ubiquitously expressed protease has chymotrypsin-like specificity and primarily targets hydrophobic stretches in selected or misfolded substrate proteins. In addition, the enzyme is capable of exerting autolytic activity by removing the N-terminal insulin-like growth factor binding protein (IGFBP)/Kazal-like tandem motif without affecting the protease activity. In this study, we have addressed the mechanism governing the autolytic activity and find that it depends on the integrity of the disulfide bonds in the N-terminal IGFBP/Kazal-like domain. The specificity of the autolytic cleavage reveals a strong preference for cysteine in the P1 position of HtrA1, explaining the lack of autolysis prior to disulfide reduction. Significantly, the disulfides were reduced by thioredoxin, suggesting that autolysis of HtrA1 in vivo is linked to the endogenous redox balance and that the N-terminal domain acts as a redox-sensing switch.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocatalysis / drug effects
  • Cysteine / chemistry
  • Cysteine / metabolism*
  • Cystine / chemistry
  • Cystine / metabolism
  • Databases, Protein
  • Dithiothreitol / pharmacology
  • Enzyme Stability / drug effects
  • Glutathione / chemistry
  • Glutathione / metabolism
  • High-Temperature Requirement A Serine Peptidase 1
  • Humans
  • Models, Molecular*
  • Osmolar Concentration
  • Oxidation-Reduction
  • Oxidative Stress
  • Peptide Fragments / chemistry
  • Peptide Fragments / metabolism
  • Protein Structure, Tertiary
  • Protein Unfolding*
  • Proteolysis* / drug effects
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Reducing Agents / chemistry
  • Reducing Agents / metabolism
  • Reducing Agents / pharmacology
  • Serine Endopeptidases / chemistry
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism*
  • Thioredoxins / chemistry
  • Thioredoxins / metabolism

Substances

  • Peptide Fragments
  • Recombinant Proteins
  • Reducing Agents
  • Cystine
  • Thioredoxins
  • High-Temperature Requirement A Serine Peptidase 1
  • HtrA1 protein, human
  • Serine Endopeptidases
  • Glutathione
  • Cysteine
  • Dithiothreitol