[Prolactin receptor: characterization by monoclonal antibodies and cloning of complementary DNA]

Rat liver prolactin receptor has been partially characterized and purified to homogeneity using monoclonal antibodies. Pure receptor was digested with trypsin and amino acid sequence of receptor fragments determined. This allowed us to clone the prolactin receptor cDNA. Our approach to clone the receptor cDNA consisted of synthesizing oligonucleotides corresponding to the amino acid sequence of receptor fragments, and to screen a cDNA library. Sequencing reveals that prolactin receptor is a 291 amino acid protein, containing an extracellular domain of 210 residues, a single transmembrane segment of 24 amino acids and a cytoplasmic domain of 57 amino acids. Introduction of the prolactin receptor cDNA into various cell types demonstrates that the single protein is sufficient to bind prolactin with the same affinity and specificity reported for the prolactin receptor.