Dual specificity phosphatase 9: A novel binding partner cum substrate of proapoptotic serine protease HtrA2

Area of Science:

• Biochemistry
• Molecular Biology
• Protease Function

Background:

• Human high-temperature requirement protease A2 (HtrA2) is a serine protease implicated in cellular processes and diseases.
• Its role as a therapeutic target necessitates understanding its interactions and binding specificities.

Purpose of the Study:

• To identify novel interacting partners and substrates of HtrA2 using an in silico approach.
• To validate predicted interactions through biochemical and cell-based assays.
• To characterize the interaction interface between HtrA2 and its novel partners.

Main Methods:

• In silico peptide library construction and binding pattern search.
• GST-pulldown and Co-Immunoprecipitation (Co-IP) assays for interaction validation.
• In vitro cleavage assays and interaction interface characterization.

Main Results:

• HtrA2 robustly interacts with Dual Specificity Phosphatase 9 (DUSP9).
• HtrA2 demonstrates in vitro cleavage activity towards DUSP9.
• Detailed characterization of the HtrA2-DUSP9 interaction interface was achieved.

Conclusions:

• HtrA2 interacts with and cleaves DUSP9, identifying DUSP9 as a novel binding partner and substrate.
• The study presents an efficient method for screening HtrA2 ligand libraries.
• Findings contribute to understanding HtrA2's mechanism of action and therapeutic potential.