Gustducin is a taste receptor cell heterotrimeric guanine nucleotide binding protein. Disclosed herein is the amino acid sequence of the gamma (.gamma.) subunit of gustducin, as well as polynucleotide sequences encoding the .gamma. subunit. Also disclosed are methods of modifying taste involving agents that inhibit or activate the gustducin .gamma. subunit, methods for identifying such taste modifying agents and various taste modifying agents.