Mitochondria regulate cell stress

Mitochondria play an unexpectedly important role in cell survival in the face of stress, according to a paper in this week's Cell. The authors suggest that this cell stress response may provide clues about how calorie restriction extends lifespan in mammals."The physiology of the mitochondria is critical for determining whether a cell lives or dies," said senior author David Sinclair of Harvard Medical School. The study shows that "cells have a very neat mechanism to try to maintain mitochondrial [energy] levels," said Shin-ichiro Imai of Washington University in St. Louis, who wasn't involved in the research. "This is important to prevent cells from [undergoing] apoptosis."Previous work has shown a connection between cellular death, organism longevity, and NAD+ (nicotinamide adenine dinucleotide), a molecule required for many metabolic processes. Severe genotoxic stress leads to loss of NAD+, which induces cell death. Recent studies have shown that cells may respond to...