Mycobacterium tuberculosis ClpP1 and ClpP2 function together in protein degradation and are required for viability in...

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Clp protease regulates stress responses in most bacteria but is typically non-essential.
• Mycobacteria possess two ClpP homologs, ClpP1 and ClpP2, within a single operon, differing from other prokaryotes.

Purpose of the Study:

• To investigate the essentiality and function of the ClpP1P2 protease complex in mycobacteria.
• To determine the role of ClpP1P2 in protein degradation and its implications for Mycobacterium tuberculosis (Mtb) growth and virulence.

Main Methods:

• Utilized promoter replacement and inducible protein degradation systems to study clpP1 and clpP2 gene expression.
• Employed active site mutants to assess the catalytic activity of ClpP1 and ClpP2 subunits.
• Investigated the degradation of missense peptides and SsrA-tagged proteins.

Main Results:

• Both clpP1 and clpP2 genes are essential for mycobacterial growth; depletion of either leads to rapid cell death.
• The ClpP1P2 protease degrades missense and prematurely terminated peptides, crucial for growth under translational stress.
• ClpP1P2 is required for degrading SsrA-tagged proteins, indicating a role in handling incomplete protein products.
• Enzymatic activity of both ClpP1 and ClpP2 subunits is necessary for proteolysis and Mtb growth in vitro and during mouse infection.

Conclusions:

• The ClpP1P2 protease complex plays an unusual and essential role in Mycobacterium tuberculosis.
• ClpP1P2's critical function in protein quality control and essentiality suggests it as a potential therapeutic target for antimycobacterial drugs.