The autolysis of human HtrA1 is governed by the redox state of its N-terminal domain.
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.
Department of Molecular Biology and Genetics, Aarhus University , DK-8000 Aarhus, Denmark.
Michael W
MW
Risør
Ebbe Toftgaard
ET
Poulsen
Line R
LR
Thomsen
Thomas F
TF
Dyrlund
Tania A
TA
Nielsen
Niels Chr
NC
Nielsen
Kristian W
KW
Sanggaard
Jan J
JJ
Enghild
D055162:Biocatalysis / Q000187:drug effects; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism*; D003553:Cystine / Q000737:chemistry / Q000378:metabolism; D030562:Databases, Protein; D004229:Dithiothreitol / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D000074289:High-Temperature Requirement A Serine Peptidase 1; D006801:Humans; D008958:Models, Molecular; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D059748:Proteolysis / Q000187:drug effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019163:Reducing Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013879:Thioredoxins / Q000737:chemistry / Q000378:metabolism
D010446:Peptide Fragments; D011994:Recombinant Proteins; D019163:Reducing Agents; D003553:Cystine; D013879:Thioredoxins; D000074289:High-Temperature Requirement A Serine Peptidase 1; C474012:HTRA1 protein, human; D012697:Serine Endopeptidases; D005978:Glutathione; D003545:Cysteine; D004229:Dithiothreitol