Functional TIM10 chaperone assembly is redox-regulated in vivo

Area of Science:

• Mitochondrial biology
• Protein folding and assembly
• Cellular respiration

Background:

• The TIM10 chaperone is essential for inserting hydrophobic proteins into the mitochondrial inner membrane.
• Understanding the assembly mechanism of TIM10 is key to comprehending mitochondrial protein import.

Purpose of the Study:

• To elucidate the novel molecular mechanism governing the assembly of the TIM10 chaperone.
• To investigate the role of oxidative folding and disulfide bonding in TIM10 complex formation.

Main Methods:

• Studied the import and folding of TIM10 subunits within mitochondria.
• Analyzed the role of conserved cysteines in disulfide bond formation during assembly.
• Differentiated between in vivo and in vitro disulfide bond formation.

Main Results:

• TIM10 assembly requires oxidative folding within mitochondria.
• Subunits are imported unfolded and reduced, then fold via intramolecular disulfide bonds.
• Intramolecular disulfide bonds stabilize an assembly-competent structure, while intermolecular bonds are non-productive.

Conclusions:

• A novel, redox-regulated mechanism governs TIM10 assembly in mitochondria.
• Compartment-specific oxidative folding is crucial for functional TIM10 chaperone formation.
• This mechanism ensures the correct assembly of TIM10 for its role in protein translocation.