Understanding cellular function to understand life

When Geoffrey Hesketh was growing up in Canada, he loved sciences and math and wanted to be a medical doctor. He became curious about molecular mechanisms after he started volunteering in a biochemistry lab in his second undergraduate year at Queen's University, and he realized that his huge curiosity would be more satisfied working as a scientist than as a physician.

Geoffrey Hesketh

Since then, Hesketh has wanted to understand molecular processes, especially those that have evolved for billions of years but that we still are far from understanding, such as cellular nutrient uptake. "Experimentally unravelling a previously obscure or unknown biological function is the ultimate scientific achievement," he said.

Now a postdoctoral fellow in Anne-Claude Gingras' group at the Lunenfeld–Tanenbaum Research Institute of Mount Sinai Hospital in Toronto, Hesketh earned a Ph.D. in biological chemistry at Johns Hopkins School of Medicine in Baltimore and then did a postdoc at the Cambridge Institute for Medical Research.

Hesketh is interested in cellular membrane trafficking and signal transduction. "If you are understanding cell function at the molecular level, you understand life," he said.

Using advanced mass spectrometry and cell biology tools, he studies the molecular mechanisms by which lysosomes control cellular nutrient biology. In nutrient signaling, mechanistic target of rapamycin complex 1, or mTORC1, plays a key role.

"Life is largely driven by the flow of key elements — carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur — in different chemical states, from organism to organism," he said.

Hesketh is fascinated by how mTORC1 is fundamental to life, participating in the sensing of the key elements, synthesis and degradation of macromolecules.

Many human diseases originate in cellular dysfunction, so Hesketh believes understanding cellular processes is the way to understand disease. Therefore, as a cellular biologist, he is pursuing his childhood interest in medicine and human diseases.