How do we sense the world around us? This is the question that drives research in the lab. The first step in sensory processing is the transduction of the sensory stimulus into an electrical signal sent to the brain. For most sensory stimuli, the receptors have been discovered, yielding insights into signal transduction, behavior and evolution. We have focused on the taste system, where receptors continue to be identified. In pursuit of the receptor for sour taste, we recently discovered a proton-selective ion channel that is expressed in cells that detect sour tastes (Tu et al, Science 2018). OTOP1 is a member of a family of proteins unrelated to other ion channels, all of which form proton channels. To understand how these channels conduct protons, in collaboration with the Ward lab at TSRI, we recently solved the structure of OTOP1 and OTOP3 (Saotome et al, NSMB 2019). These studies pave the way for future work aimed at understanding how these channels are activated and how they achieve such high selectivity for protons. The lab showed that OTOP1 is requried for sour taste signaling in isolated cells and in animals (Teng et al, Curr Biol, 2019) and more recently (Liang et al, Nat Comm, 2023) that it is required for a component of ammonium taste. Thus, OTOP1 is a proton channel that functions as a pH sensor in the taste system, detecting both changes in extracellular pH (sour tastes) and intracellular pH (ammonium).
OTOP1 is also found in the vestibular system and brown adipose tissue while related channels OTOP2 and OTOP3 are found in the digestive tract and nervous sytem. Our studies lay the groundwork for future work aimed at understanding the contribution of OTOP1 and other members of the protein family to signaling in a variety of cellular contexts, in health and disease.
EMILY LIMAN, PhD
Professor of Biological Sciences, Sections of Neurobiology and Molecular and Computational Biology
Professor Liman earned her A.B. from Princeton University Magna Cum Laude and earned a Ph.D. from Harvard University in Neuroscience. She is the 2023 recipient of the Cole award from the biophysical society.
October 2023. OTOP1 is a sensor for the taste of ammonium chloride. Congratulations Ziyu Liang and Courtney Wilson!
Emily is elected to chair the 2024 meeting of the Association for Chemoreceptive Sciences
November 2021. Emily chairs and speaks at the SFN 50th anniversary meeting (virtual)
October 2021. Bochuan defends his PhD - congratulations Bochuan!
May 2021. Ziyu Liang and Josh Kaplan join the lab as PhD students - welcome!
September 2019. We report that OTOP1 is a sour receptor (for sure!).
Teng et al, Curr Biol, 2019. (link)
July 2019. The lab is awarded two NIH R01 grants!
June 2019. Nature Structure and Molecular Biology paper reporting the structures of OTOP1 and OTOP3. A great collaboration with Andrew Ward's lab (TSRI)
Saotome et al, Nature Structure Molecular Biology, 2019 (link)
March 2, 2018. We report that OTOP1 is a novel proton-selective ion channel, expressed in sour taste cells
Tu et al, Science 2018 link
On Tu et al (Science, 2018).Biotechniques, New York Times (2018): Unlocking Secrets of Sour Flavors With Something Found in Your Ears
Research in the Liman Lab is supported by the NIH