Lysosomal mTORC2/PHLPP1/Akt Regulate Chaperone-Mediated Autophagy.

Area of Science:

• Cellular Biology
• Molecular Biology
• Biochemistry

Background:

• Chaperone-mediated autophagy (CMA) is a crucial lysosomal degradation pathway for cytosolic proteins, essential for proteostasis and stress adaptation.
• While CMA substrate targeting and translocation are understood, the regulatory mechanisms governing CMA remain largely unknown.

Purpose of the Study:

• To identify novel regulators of chaperone-mediated autophagy (CMA).
• To elucidate the role of the PHLPP1 phosphatase in CMA regulation.

Main Methods:

• Investigated the interaction of PHLPP1 with the lysosomal membrane.
• Analyzed the effect of PHLPP1 on mTORC2 activity and its impact on CMA.
• Examined the role of lysosomal Akt in modulating CMA translocation complex dynamics.

Main Results:

• Identified PHLPP1 as a positive regulator of CMA that counteracts mTORC2-mediated inhibition.
• Demonstrated that lysosomal Akt, regulated by the mTORC2/PHLPP1 axis, controls the assembly and disassembly of the CMA translocation complex.
• Established a novel lysosomal mTORC2/PHLPP1/Akt signaling pathway influencing CMA activity.

Conclusions:

• The PHLPP1 phosphatase positively controls CMA by antagonizing mTORC2.
• The mTORC2/PHLPP1/Akt pathway at the lysosome regulates CMA translocation complex dynamics.
• This pathway represents a potential therapeutic target for restoring CMA function in aging and disease.