The yeast α-factor receptor: Structural properties deduced from the sequence of the STE2 gene

The STE2 gene of the yeast Saccharomyces cerevisiae encodes a component of the receptor for the oligopeptide pheromone α-factor (1). We have cloned and determined the nucleotide sequence of the STE2 gene. A sequence involved in the control of cell-type expression of the STE2 gene (2,3) was found 5′ of an open reading frame that could encode a protein of 431 amino acids. The predicted STE2 protein contains seven hydrophobic segments, suggesting that the α-factor receptor is an integral membrane protein. No extensive homology at the primary sequence level was detected between the predicted STE2 protein and other available protein sequences.