V-ATPase: a master effector of E2F1-mediated lysosomal trafficking, mTORC1 activation and autophagy

Area of Science:

• Cell Biology
• Molecular Oncology
• Cancer Biology

Background:

• E2F1 is a key regulator of cell cycle, growth, and malignancy.
• Lysosomal trafficking and mTORC1 signaling are crucial for cell growth and survival.
• Autophagy is a cellular process involved in maintaining homeostasis and preventing disease.

Purpose of the Study:

• To investigate the regulatory network linking E2F1 to lysosomal trafficking and mTORC1 signaling.
• To elucidate the role of v-ATPase in E2F1-mediated cellular processes.
• To explore the therapeutic potential of targeting v-ATPase in E2F1-overexpressing tumors.

Main Methods:

• Immunofluorescence and time-lapse microscopy to observe lysosomal movement.
• Gain- and loss-of-function experiments to assess E2F1 and v-ATPase roles.
• Immunoprecipitation to study protein interactions.
• Analysis of v-ATPase subunit expression and functional assays.

Main Results:

• E2F1 induces lysosomal trafficking to the cell periphery, activating mTORC1 and repressing autophagy.
• E2F1 regulates v-ATPase activity, and v-ATPase inhibition blocks E2F1-induced effects.
• E2F1 recruits v-ATPase to RagB GTPase, enhancing v-ATPase complex association.
• ATP6V0B is identified as a transcriptional target of E2F1, mediating its effects on v-ATPase and mTORC1 activity.

Conclusions:

• E2F1 controls lysosomal trafficking and mTORC1 signaling via v-ATPase regulation.
• ATP6V0B is a key mediator of E2F1's function in this pathway.
• Targeting v-ATPase may offer a therapeutic strategy for metastatic cancers with high E2F1 expression.