A new member of the acid-sensing ion channel family

Acid-sensing ion channels (ASICs) are members of the epithelial sodium chan nel (ENaC)-degenerin family of two-pass transmembrane segment protein subun its which form multimeric cation channels. Members of the ENaC-degenerin fa mily are gated by stimuli as diverse as protons, peptides and mechanical di stension. Here we describe a new member of the family, SPASIC or ASIC 4 (sp inal cord ASIC) which is expressed throughout the central nervous system in an overlapping population of neurons that also express the ASIC subunit MD EG2. ASIC-4 which shows 44% identify with ASIC is developmentally regulated and expressed in a subset of sensory neurons as well as in the CNS. Howeve r, despite the strong homology with ASIC, the ASIC-4 transcript does not en code a proton gated cation channel. NeuroReport 11:2217-2222 (C) 2000 Lippi ncott Williams & Wilkins.