Campus Connection

From big lizards to astrocytomas
(continued)

Cala's initial research is seemingly unrelated to cancer: a protein responsible for a process called the sodium-proton exchange (Na+/H+) exchange. The journey from this enzyme to astrocytomas is steeped in serendipity.

Cala, a professor and chair of the Department of Human Physiology at UC Davis, has long been interested in how cells regulate their volume - or water content - and their pH, a measurement of acidity versus alkalinity.

Cell volume is "the defining characteristic of a cell - it's like a fingerprint for a particular cell type," says Cala.

"Even if you osmotically shrink a cell, it is able to regulate its volume back to normal levels. It does something to return to normal volume by bringing solute (salt) and water into the cell across the membrane."

Cala identified an enzyme that transports sodium ions into the cell in exchange for extracellular hydrogen ions (protons) in a one-for-one exchange, "like a revolving door," he says.