title: Cloning of a pH-sensitive K+ channel possessing two transmembrane segments.
abstract: The mammalian renal collecting ducts are responsible for secreting potassium ions into the urine and are a major regulatory site for potassium homeostasis, in which a voltage-independent pH-sensitive K+ channel in the apical membrane plays a central role. Here we describe a complementary DNA encoding a novel K+ channel from rabbit renal cortical collecting tubule cells (RACTK1). RACTK1 has the functional characteristics of the apical K(+)-permeable channel and consists of 284 amino acids, putatively with two transmembrane segments. The sequence of RACTK1, however, shows no homology to known voltage-dependent or -independent K+ channels, and has a different K(+)-driving path and regulatory sites. The study of this protein should provide insight into K+ homeostasis and diseases of K+ metabolism.
authors.affiliation: Department of Pharmacology, Jichi Medical School, Tochigi, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Ikeda
authors.forename: H
authors.initials: H
authors.lastname: Hayakawa
authors.forename: A
authors.initials: A
authors.lastname: Ogawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: O
authors.initials: O
authors.lastname: Sakai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D007685:Kidney Tubules, Collecting / Q000737:chemistry* / Q000502:physiology; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D011817:Rabbits; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D015221:Potassium Channels; C085904:RACTK1 protein, Oryctolagus cuniculus