:: By Ethan D. Frenchman, ‘08

:: Photography by Dan Dry

Investigations ::

Laser beads

In a subbasement laboratory at the Gordon Center for Integrative Sciences, assistant professor of biochemistry Ron Rock, SB’92, and his assistants use lasers to uncover the mysteries of motility—how molecules move within cells. The underground lab keeps the custom-made microscopes, cameras, and lasers free from trucks’subtle vibrations on the street above, allowing measurements at an “almost atomic resolution.”

The team uses an infrared laser to suspend a plastic bead—1/100th the width of a human hair—in midair, attaching it to the protein myosin. Myosin, he explains, moves “cargo” such as mitochondria around a cell on a “track” known as an actin filament, much as a truck moves its cargo down a road. Once attached, the laser places the bead and myosin molecule onto the actin-filament.

The goal is to understand how certain myosin molecules read cellular “road maps” in order to perform their various functions, says Rock. Humans have 40 different myosin molecules, each with its own role. Some are responsible for moving entire cells, explaining how malignant tumors can spread through the body, while others heal wounds or assist in hearing. “All these motors know how to get to specific locations and do what they need to do,” Rock says. Cell migration, seen in cancer, “is a new realm for these motors. It’s an area that we are just now getting into and appreciate in the last six months or so.” Rock is already on his way, researching how certain myosin molecules may move down not only one actin filament, but two adjacent filaments.