Ž . Biochimica et Biophysica Acta 1395 1998 301–308 Short sequence-paper Isolation, molecular characterization, and tissue-specific expression of a novel putative G protein-coupled receptor Herbert Mayer a,1 , Ulrich Salzer a,1 , Johannes Breuss b , Sophie Ziegler b , Aron Marchler-Bauer c , Rainer Prohaska a, ) a Institute of Biochemistry, UniÕersity of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9 r 3, A-1030 Vienna, Austria b Department of Vascular Biology and Thrombosis Research, UniÕersity of Vienna, A-1090 Vienna, Austria c Research Institute of Molecular Pathology, A-1030 Vienna, Austria Received 15 July 1997; revised 10 September 1997; accepted 19 September 1997 Abstract Ž . We isolated a 40 kDa integral membrane protein p40 from human erythrocyte ghosts by affinity chromatography, using a C-terminal peptide of stomatin, and obtained partial sequences which enabled us to isolate two full-length cDNAs from human bone marrow and fetal brain cDNA libraries. The cDNA sequences were identical and encoded a novel putative G Ž . protein-coupled receptor 399 amino acids . Northern and RNA dot blot analyses demonstrated that the major 4.8 kb-tran- script is predominantly expressed in brain. In situ hybridization studies of tissue sections revealed high expression in neurons of the brain and spinal cord, in thymocytes, megakaryocytes, and macrophages. q 1998 Elsevier Science B.V. Keywords: G protein-coupled receptor; Membrane protein; Erythrocyte; Neuron; Stomatin; In situ hybridization The human erythrocyte membrane was frequently used for the primary isolation and characterization of widely distributed membrane proteins like the glu- wx wx cose transporter 1 , anion transporter 2 , water chan- wx wx nel 3, complement receptor 4, and Duffy wx chemokine receptor 5 , apart from the major cyto- skeletal components. We have been studying the w x erythrocyte membrane protein 7.2b 6–8 , also termed wx stomatin 9 , which is expressed in various tissues w x 9,10 . Its function is not known, however, because of ) Corresponding author. Fax: q43 1 79515 3114; E-mail: prohaska@bch.univie.ac.at 1 Contributed equally to this study. its absence in the high Na q , low K q red cells of patients with overhydrated hereditary stomatocytosis w x 9,11,12 . It has been hypothesized that it may act as w x a regulator of an ion channel 13 in association with w x the cytoskeleton 14 . Such an association has par- tially been proven for the Caenorhabditis elegans w x stomatin-like protein MEC-2 15 , which is a neces- sary component of the mechanosensory apparatus. There is indirect evidence that human stomatin is w x associated with the cytoskeleton 14,16 , but so far an associated ion channel or receptor has not been iden- tified. In the present study we describe the isolation of the membrane protein p40 by stomatin peptide-af- finity chromatography, the cloning and characteriza- tion of the corresponding cDNA, and the tissue- specific expression. 0167-4781r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0167-4781 97 00178-4