A new member of acid-sensing ion channels from pituitary... : NeuroReport (original) (raw)
SYNAPTIC TRANSMISSION
Gründer, Stefan1,3; Geissler, Hyun-Soon1; Bässler, Eva-Lotta1; Ruppersberg, J Peter2
1Department of Otolaryngology, Section of Sensory Biophysics, Röntgenweg II, Germany
2Department of Physiology, Gmelinstr. 5, D-72076 Tübingen, Germany
3Corresponding Author: Stefan Gründer
Acknowledgements: We are grateful to Dr T.J. Jentsch for the gift of the rat brain cDNA library, to Dr M. Praetorius for preparation of DRGS, to Dr J. Schwarz for the gift of the GH3 cells and to Dr H.-P. Zenner for his generous support throughout this study. This work was supported through the Hörforschungszentrum Baden-Württemberg.
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.
© 2000 Lippincott Williams & Wilkins, Inc.