Characterizing global translation and mitochondrial protein import in senescence using mePROD and mePRODmt

During aging, senescent cells accumulate in the human body. These cells are characterized by irreversible cell-cycle arrest, pro-inflammatory phenotype, and decline in proteostasis. Senescence also leads to changes in mitochondria, including enlargement, increased mass, reduced ATP production, and decreased membrane potential. These alterations likely affect mitochondrial protein import (MPI) that relies partly on membrane potential and ATP. Consequently, MPI impairment is highly plausible in aged mitochondria. Despite the significance of MPI, the impact of senescence on this process is largely unknown. This project aims to address this knowledge gap using mePRODmt, a SILAC-based proteomics approach for quantifying protein uptake into mitochondria. Since import and translation are closely related, we measured translation using the global SILAC-based proteomics approach mePROD. We induced senescence in three different ways in human lung fibroblasts (IMR90) and measured import and translation over the course of senescence transition. To further investigate alterations in MPI during senescence and examine affected signaling pathways in the senescent phenotype, we performed phospho-proteomics. Understanding the impact of senescence on translation and mitochondrial protein import is crucial for unraveling the complex interplay between aging, cellular homeostasis, and neurodegenerative diseases.