title: A new member of acid-sensing ion channels from pituitary gland.
abstract: Acid-sensing ion channels (ASICs) constitute a branch of the super-gene family of amiloride-sensitive sodium channels. So far five different ASICs have been cloned from mammalian tissues. They are activated by a drop of extracellular pH but differ with respect to effective agonist concentration, desensitization and mRNA expression pattern. Here we report cloning of ASIC4, a new protein showing about 45% identity to other ASICs. ASIC4 is 97% identical between rat and human and shows strongest expression in pituitary gland. Moreover, we detected expression throughout the brain, in spinal cord, and inner ear. ASIC4 cannot be activated by a drop of extracellular pH in Xenopus oocytes, suggesting association with other subunits or activation by a ligand different from protons. Our results suggest a role for ASICs also in endocrine glands.
authors.affiliation: Department of Otolaryngology, Section of Sensory Biophysics, Tübingen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Gründer
authors.forename: H S
authors.initials: HS
authors.lastname: Geissler
authors.forename: E L
authors.initials: EL
authors.lastname: Bässler
authors.forename: J P
authors.initials: JP
authors.lastname: Ruppersberg
mesh_terms: D062565:Acid Sensing Ion Channels; D000595:Amino Acid Sequence / Q000235:genetics; D019943:Amino Acid Substitution / Q000235:genetics / Q000502:physiology; D000818:Animals; D001921:Brain / Q000378:metabolism; D003001:Cloning, Molecular; D007758:Ear, Inner / Q000378:metabolism; D004594:Electrophysiology; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D009865:Oocytes / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D013116:Spinal Cord / Q000378:metabolism; D014018:Tissue Distribution; D014981:Xenopus
chemical_list: C112231:ASIC3 protein, human; C568270:ASIC4 protein, human; D062565:Acid Sensing Ion Channels; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D015222:Sodium Channels