Metabolism

Prize bestowed for discovery of the mTOR pathway’s impact on age-related diseases

Parkinson’s disease (PD) and other “synucleinopathies” are known to be linked to the misfolding of alpha-synuclein protein in neurons. Less clear is how this misfolding relates to the growing number of genes implicated in PD through analysis of human genetics. Two new studies from researchers affiliated with Whitehead Institute and Massachusetts Institute of Technology explain how they used a suite of novel biological and computational methods to shed light on the question.

Whitehead Institute researchers have elucidated how the growth-regulating metabolic pathway known as mTORC1 (for mechanistic target of rapamycin complex 1) senses the amino acid arginine. This nutrient sensor may represent a novel therapeutic target for controlling mTORC1, whose activity is often dysregulated in a variety of diseases, including diabetes and cancer. 

Whitehead Institute scientists have at last answered the long-standing question of how the growth-regulating pathway known as mechanistic target of rapamycin complex 1 (mTORC1) detects the presence of the amino acid leucine—itself a key player in modulating muscle growth, appetite, and insulin secretion.

Countering the prevailing theory that cellular hydrogen peroxide signaling is broad and non-specific, Whitehead Institute scientists have discovered that this reactive oxygen species (ROS) in fact triggers a distinct signal transduction cascade under control of the mitochondrial respiratory chain—the Syk pathway—that regulates transcription, translation, metabolism, and the cell cycle in diverse cell types. Hydrogen peroxide and other ROS mediate cellular responses in aging and myriad common chronic diseases, including diabetes, heart disease, stroke, cancer, and neurodegeneration. Understanding how these signals function may point to new therapy targets for these conditions.

According to Whitehead Institute researchers, cells with malfunctioning mitochondria are unable to proliferate due to a shortage of the amino acid aspartate, not because of an energy crisis, as was once thought. Mitochondrial dysfunction plays a role in a host of relatively rare disorders as well as neurodegenerative disorders, including Parkinson’s disease.

Whitehead Institute Member Jing-Ke Weng is among 15 young scientists nationwide to be named a 2015 Searle Scholar.

Biologists at Whitehead Institute and MIT have discovered a vulnerability of brain cancer cells that could be exploited to develop more-effective drugs against brain tumors.

Scientists in the lab of Whitehead Institute Member David Sabatini have for the first time identified a protein that appears to be a nutrient sensor for the key growth-regulating mTORC1 metabolic pathway. 

Protein production or translation is tightly coupled to a highly conserved stress response—the heat shock response and its primary regulator, heat shock factor 1 (HSF1)—that cancer cells rely on for survival and proliferation, according to Whitehead Institute researchers. In mouse models of cancer, therapeutic inhibition of translation interrupts HSF1’s activity, dramatically slowing tumor growth and potentially rendering drug-resistant tumors responsive to other therapies.