The Drosophila Rhomboid protein has been implicated in the modulation of epidermal growth factor receptor (see 131550) signaling. By searching sequence databases for Rhomboid homologs, Pascall and Brown (1998) identified a human genomic clone containing the RRP (Rhomboid-related protein) gene. Using a PCR strategy with cDNA derived from a human leukemic cell line, the authors cloned cDNAs corresponding to the entire RRP coding region. Sequence analysis indicated that the predicted 438-amino acid protein has 7 transmembrane domains and an intracellular N terminus. RRP and Rhomboid share 30% amino acid sequence identity. By Northern blot analysis, Pascall and Brown (1998) determined that RRP is expressed as a 1.7-kb mRNA in brain and kidney; larger transcripts were detected in heart, skeletal muscle, and brain.