Anoctamin 2 (ANO2 or TMEM16B), a calcium-activated chloride channel (CaCC), performs diverse roles in neurons throughout the central nervous system. In hippocampal neurons, ANO2 narrows action potential width and reduces postsynaptic depolarization with high sensitivity to Ca2+ at relatively fast kinetics. In other brain regions, including the thalamus, ANO2 mediates activity-dependent spike frequency adaptations with low sensitivity to Ca2+ at relatively slow kinetics. How this same channel can respond to a wide range of Ca2+ levels remains unclear. We hypothesized that splice variants of ANO2 may contribute to its distinct Ca2+ sensitivity, and thus its diverse neuronal functions. We identified two ANO2 isoforms expressed in mouse brains and examined their electrophysiological properties: isoform 1 (encoded by splice variants with exons 1a, 2, 4, and 14) was expressed in the hippocampus, while isoform 2 (encoded by splice variants with exons 1a, 2, and 4) was broadly expressed throughout the brain, including in the cortex and thalamus, and had a slower calcium-dependent activation current than isoform 1. Computational modeling revealed that the secondary structure of the first intracellular loop of isoform 1 forms an entrance cavity to the calcium-binding site from the cytosol that is relatively larger than that in isoform 2. This difference provides structural evidence that isoform 2 is involved in accommodating spike frequency, while isoform 1 is involved in shaping the duration of an action potential and decreasing postsynaptic depolarization. Our study highlights the roles and molecular mechanisms of specific ANO2 splice variants in modulating neuronal functions.

Background: The need for regulatory science development to evaluate advanced regulatory products is gradually increasing without hindering the technological development. Creating a research environment and fostering experts through the establishment of regulatory agency-led policies are essential for the development of regulatory science. Method: This is a comparative study of the United States, Japan, Singapore, and Korea. The literature and websites of each regulatory agency were reviewed, and the focus was on advantages and comparing advantages based on definition, development trends, and expert training projects. Results: The United States is striving to develop regulatory science in response to changes in the new pharmaceutical industry through the regulatory science report, and to foster expert both inside and outside the Food and Drug Administration (FDA). Japan is promoting regulatory science centered on regulatory science centers, and is focusing on researching work-related regulatory science within the Pharmaceuticals and Medical Devices Agency (PMDA) and improving employees’ ability to make regulatory decisions. Singapore was aiming to improve Southeast Asia’s regulatory capabilities under the leadership of Centre of Regulatory Excellence (CoRE) within Duke-NUS University. In 2021, Korea is in its early stages, starting to run a university's degree program related to regulatory science this year. Conclusion Regulatory science should be developed with the aim of improving the regulatory ability of the Ministry of Food and Drug Safety with Korea’s independent concept of regulatory science.