06 Apr 2000

Conventional wisdom has it that each member of the large G protein-coupled receptor (GPCR) family pairs up exclusively with another of its own kind. But a new study in tomorrow's Science reports that two different GPCRs, mediating the activity of the neurotransmitters somatostatin and dopamine, defy convention by coupling with each other. These molecular miscegenators are the D2R dopamine receptor and SSTR5 somatostatin receptor. "These findings have caused something of a shock," Graeme Milligan writes in a related Perspective. Because the GPCR family is probably the largest in the human genome, the number of possible GPCR combinations that may participate in cells signaling is "truly bewildering," according to Milligan.—Hakon Heimer