Mitochondrial Lon regulates apoptosis through the association with Hsp60-mtHsp70 complex

Area of Science:

• Mitochondrial biology
• Cancer research
• Proteomics

Background:

• Human Lon protease is a mitochondrial matrix protein involved in protein degradation, mtDNA binding, and chaperone activity.
• Overexpression of Lon protease in cancer cells suggests its role in mitochondria-driven tumorigenesis.

Purpose of the Study:

• To elucidate the mechanism of Lon protease overexpression in tumor cells.
• To identify Lon-associated proteins and understand their role in cellular processes.

Main Methods:

• Utilized a proteomics approach combining co-immunoprecipitation (Co-IP) with in-solution digestion for shotgun mass spectrometry.
• Investigated Lon-associated proteins in cells overexpressing Lon protease.

Main Results:

• Identified 76 putative Lon-associated proteins involved in mitochondrial chaperone systems, metabolism, cell death, and mtDNA stability.
• Confirmed the association between Lon and NDUFS8 or the Hsp60-mtHsp70 complex via Co-IP and immunofluorescence.
• Demonstrated that Lon protease maintains Hsp60-mtHsp70 complex stability under oxidative stress and inhibits apoptosis by Hsp60 binding to p53.

Conclusions:

• Lon protease regulates cell survival through the Hsp60-mtHsp70 complex, impacting apoptosis and potentially promoting tumorigenesis.
• Understanding the Lon interactome provides insights into mitochondrial function and Lon's role in cancer cell survival.