Progesterone binding protein is a putative steroid membrane receptor. The protein is expressed predominantly in the liver and kidney.Progesterone binding protein is a putative steroid membrane receptor. The protein is expressed predominantly in the liver and kidney. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Entrez Gene record to access additional publications.Progesterone binding protein is a putative steroid membrane receptor. The protein is expressed predominantly in the liver and kidney. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Entrez Gene record to access additional publications.