InterPro domain: IPR004254

Members of this family are integral membrane proteins. This family includes a protein with hemolytic activity from Bacillus cereus [ 1 ]. YOL002c (AdipoR-like receptor IZH2) from Saccharomyces cerevisiae encodes a protein that plays a key role in metabolic pathways that regulate lipid and phosphate metabolism [ 2 , 3 ]. In eukaryotes, members are seven-transmembrane pass molecules found to encode functional receptors with a broad range of apparent ligand specificities, including progestin and adiponectin (AdipoQ) receptors (AdipoR), and hence have been named PAQR proteins [ 4 ]. The mammalian members include progesterone binding proteins [ 5 ]. Unlike the case with GPCR receptor proteins, the evolutionary ancestry of the members of this family can be traced back to the Archaea.

1. Cloning and primary structure of a new hemolysin gene from Bacillus cereus. Biochim. Biophys. Acta 1264, 151-4
2. Multiple regulatory roles of a novel Saccharomyces cerevisiae protein, encoded by YOL002c, in lipid and phosphate metabolism. J. Biol. Chem. 277, 19609-17
3. Osmotin is a homolog of mammalian adiponectin and controls apoptosis in yeast through a homolog of mammalian adiponectin receptor. Mol. Cell 17, 171-80
4. PAQR proteins: a novel membrane receptor family defined by an ancient 7-transmembrane pass motif. J. Mol. Evol. 61, 372-80
5. Steroid and G protein binding characteristics of the seatrout and human progestin membrane receptor alpha subtypes and their evolutionary origins. Endocrinology 148, 705-18