Protein with dual role in regulation of cellular processes

The unique dual-action role of a natural regulatory protein that controls cellular function has been described by researchers at the University of California, San Diego (UCSD) School of Medicine.

According to Marilyn Farquhar, chair of UCSD's Department of Cellular and Molecular Medicine, the findings are important to the scientific community because they link previously unconnected areas and offer new avenues of disease research.

"For example," she added, "these findings offer potential targets for the development of new drugs to help people with heart failure, hormone imbalances and cancer, which are all linked to flaws in cell signaling or trafficking."

In its cell-signaling role, RGS-PX1 regulates a molecular on-off switch called a G protein alpha (Ga) subunit, which is important for cellular processes that affect a variety of conditions such as normal heart beat, hormone secretion, and kidney function. When RGS-PX1 is present, the Ga subunit activity is turned off.

In normal activity, when cell growth is completed, growth factor receptors cease their activity. RGS-PX1 delays the natural degradation of growth factor receptors and, instead, allows cells to continue to proliferate, such as in the growth of cancerous tumors.

"Now we need more studies to determine other molecules involved and how RGS-PX1 is activated in its regulation of cell signaling and growth factor trafficking," Bin Zheng, a graduate student in UCSD's Molecular Pathology Graduate Program, said.