The discovery was made in the laboratory of Joel H. Rothman, professor of molecular, cellular and developmental biology at the University of California, Santa Barbara. It was described in a paper published in the May issue of the journal Developmental Cell, the most widely cited journal in developmental biology. In addition to Rothman, the authors of the paper are: Kenji Kontani (first author) who has moved on to the University of Tokyo, Japan, and Ivan P.G. Moskowitz (second author) now at Harvard University.

Rothman explained that cell fusion is analogous to the melding of soap bubbles, and the process is involved in creating many of our organs, 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."

Fusion is the process that allows a sperm to fertilize an egg; it also allows a cancer cell to join with a normal cell. The discovery by Rothman and his co-authors reveals that the inappropriate joining of cells by fusion 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.

The protein, vacuolar ATPase, was already 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 pos
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Contact: Gail Gallessich
gail.g@ia.ucsb.edu
805-893-7220
University of California - Santa Barbara
20-May-2005