By Gail Gallessich

	UCSB’s Joel H. Rothman, professor of molecular, cellular, and developmental biology, was part of a research team that discovered a new way to control fusion of cells.

A recent discovery in cellular biology may allow scientists to enhance organ regeneration by stem cells, prevent the progression of cancer, and control fertility.

The discovery was made in the laboratory of Joel H. Rothman, professor of molecular, cellular, and developmental biology, and described in a paper in the May issue of the journal Developmental Cell.

Rothman explained that cell fusion is analogous to the melding of soap bubbles, and the process is involved in creating many human tissues, including muscles, bones, and placentas. “When a cell fuses with others, it loses its individuality,” said Rothman. “But it can also adopt a new career, either productive, as when stem cells regenerate organs, or sinister, as in cancer metastasis.”

The discovery by Rothman and his co-authors reveals that inappropriate fusing of cells is naturally prevented by a familiar protein, called vacuolar ATPase, acting in an entirely unanticipated context. The discovery suggests new avenues for pharmaceutical companies to develop drugs to enhance organ regeneration by stem cells, prevent cancer progression, and control fertility.

Vacuolar ATPase was known to make certain compartments inside a cell become more acidic, an essential function in cell biology. Now it is understood that the protein also works on the surface of the cell to prevent cell fusion.

“The protein is in an unexpected place, doing an unexpected job,” said Rothman. “This finding might make it possible to develop new methods, and new drugs, for controlling cell fusion.” In addition to Rothman, the other authors are: Kenji Kontani (first author) who has moved on to the University of Tokyo, Japan, and Ivan P.G. Moskowitz now at Harvard University.

The new discovery makes known a protein that prevents cell fusion from happening inappropriately. “It’s as if we now have a yin and yang of cell fusion,” he said.