As skeletons go, our cells bear greater resemblance to Marvel’s Mr. Fantastic or Pixar’s Elastigirl than we do.
A cell’s skeleton is a fluid network of protein chains, or polymers, that disassemble and reassemble in new locations, branching out, pushing forward and causing the cell to move quickly in any direction. And often, the cell is chasing a bad guy - a bacterium or other pathogen - making it a superhero in its own way.
UC Merced professor
Ajay Gopinathanstudies the
physics of cytoskeletons- how they form and interact with the cell membrane to cause motion.
“If we can understand how these processes work, it will give us a better handle on tuning them,” Gopinathan said. “It could impact cancer treatments or methods of drug delivery, for example.”
He explained that cell movement is an important factor in metastasizing tumors, describing the motility of cancer cells as “haywire.” If that could be controlled, it could limit the spread of cancer.
As for drug delivery, Gopinathan points to Listeria bacteria that ride the growing ends of polymer chains, sometimes using the surprising force of the growing chain to push them outward through the membrane and infect other cells. Medicines engineered to leverage the cytoskeleton that way could be rapidly and powerfully distributed from cell to cell.
Recently, Gopinathan has ventured into a slightly different field of research - how polymers cross cell membranes. Speed is critical; fuel, chemical signals and genetic information must be delivered at the right time. And the polymers aren’t crossing into open space. The interior of a cell is crowded with organelles, free-floating proteins and of course the jungle-gym structure of the cytoskeleton.
In a surprising finding, he and his co-author have concluded that after a certain point, the length of a polymer doesn’t affect the time it takes for the chain to cross the membrane. They have published their results on polymers crossing into crowded spaces in a recent issue of Physical Review Letters.
Like his
researchsubjects, Gopinathan has to cross boundaries for his work - bringing together
physicsand
biologyin innovative ways. For example, he’s involved with developing a calculus-based first-year physics sequence for biology majors.
“We have made this as mathematically rigorous as the standard physics sequence,” Gopinathan said. “The course will utilize examples and applications in biology to motivate and explain topics in physics.”
It may not make him Mr. Fantastic, but at an up-and-coming university that emphasizes interdisciplinary research, it’s a pretty impressive line of work.
