image: This is the tunicate, Oikopleura dioica. view more
Credit: PNAS
A study explores the evolution of acid-sensing ion channels (ASICs). ASICs are membrane-bound proteins that convert extracellular stimuli into electrical signals in neurons, conveying information throughout the nervous system. ASICs were thought to be specific to the vertebrate nervous system, despite the homology of other ion channels in vertebrates and invertebrates. Timothy Lynagh and colleagues used molecular phylogenetic analysis and electrophysiological recordings to study the evolutionary history of ASICs. The authors report the presence of ASICs in invertebrates, including sea urchins, starfish, and tunicates, suggesting that ASICs evolved more than 600 million years ago. Moreover, a comparison of broadly-related ASICs revealed key molecular determinants of ASIC proton sensitivity, enabling the authors to establish that proton sensitivity of the ASIC4 isoform was lost during the evolution of mammals. The findings suggest that acid receptors in the nervous system evolved earlier than previously thought and are likely widespread across numerous animal species, according to the authors.
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Article #18-06614: "Acid-sensing ion channels emerged over 600 Mya and are conserved throughout the deuterostomes," by Timothy Lynagh, Yana Mikhaleva, Janne Colding, Joel Glover, and Stephan Pless.
MEDIA CONTACT: Timothy Lynagh, University of Copenhagen, DENMARK; e-mail: tpl@sund.ku.dk
Journal
Proceedings of the National Academy of Sciences