CLONING AND SEQUENCING OF THE CDNA-ENCODING FOR A NA+ H+ EXCHANGER FROM XENOPUS-LAEVIS OOCYTES (X1-NHE)/

We have cloned and sequenced the cDNA for a Na+/H+ exchanger(NHE) from Xenopus laevis oocytes. This cDNA contains an open reading frame enco ding a protein of 782 amino acids with 12 putative transmembrane domai ns and a long cytoplasmic tail. The protein exhibits a strong homology at the amino acid level to the human NHE-1 as well as to the beta NHE from trout red blood cells: 69% and 58% respectively. Two potential N -linked glycosylation sites at Asn(56) and Asn(351) were identified. T hree potential protein kinase C phosphorylation sites at the cytoplasm ic tail were identified at Ser(494), Thr(726) and Ser(747). RT-PCR rev ealed the expression of the X1-NHE in Xenopus heart, reticulocytes and skeletal muscle. (C) 1997 Elsevier Science B.V.