We have characterized the PRL receptor (PRL-R) present in mouse liver by purification, cross-linking, and immunological analysis of the protein, and by the isolation of PRL-R cDNA clones. Analysis of the cDNA clones indicates that the liver receptor is actually a family of proteins. Two of these proteins are predicted to be synthesized as precursors of 303 and 292 amino acids, with common signal sequences, extracellular domains, and transmembrane domains; a portion of their cytoplasmic domains are also identical, but these proteins differ markedly in the terminal region of this domain. A third PRL-R protein is predicted to be a truncated form and may be secreted. These multiple PRL-R mRNAs appear to be encoded by at least two genes, with the sequence variation for the two full-length proteins likely due to alternative RNA splicing. These results suggest that the varied actions of PRL may involve multiple receptors that are part of distinct signal transduction pathways.
ASJC Scopus subject areas
- Molecular Biology