{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T18:07:15Z","timestamp":1789150035788,"version":"build-2803163510"},"reference-count":48,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Appalachian Career Training in Oncology (ACTION) Program","award":["R25 CA221765"],"award-info":[{"award-number":["R25 CA221765"]}]},{"name":"NCI-funded Youth Enjoy Science (YES) R25 Program"},{"name":"Gatton Research Internship Grant"},{"name":"Alumni of the research group"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Membranes"],"abstract":"<jats:p>Cells exhibit a membrane potential due to the differential distribution of ions and the density of channels, pumps, and exchangers. It is known in larval Drosophila that the membrane potential gravitates towards the equilibrium potential of K+ due to the high density of K2P channels. Higher extracellular Ca2+ ([Ca2+]o) tends to drive the resting membrane potential to a more negative state, while lowering it has an opposite effect. The expression of the K2P channel and NALCN was altered genetically to determine the sensitivity to changes in [Ca2+]o, and computational simulations using the theoretical Goldman-Hodgkin-Katz equation allowed estimating changes in ion (Na+) permeability due to altered function of the NALCN. Increasing [Ca2+]o hyperpolarized the membrane potential, and decreasing [Ca2+]o depolarized it, likely because Ca2+ ions block NALCN. An accessory protein to NALCN and NALCN itself were targeted by RNAi. Overexpression of K2P channels and decreased NALCN function reduced the effect of altered [Ca2+]o on membrane potential. Given the limited understanding of how altered membrane potentials affect cells, this study provides a foundation for future investigations into how cells respond to variations in [Ca2+]o under altered K2P and NALCN expression.<\/jats:p>","DOI":"10.3390\/membranes16090298","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T17:14:59Z","timestamp":1789146899000},"page":"298","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Effects of Ca2+ on Membrane Potential with Altered Function of NALCN and K2P Channels"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-7741-7779","authenticated-orcid":false,"given":"Youngwoo","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Biology, University of Kentucky, Lexington, KY 40506, USA"},{"name":"The Gatton Academy, 1906 College Heights Blvd. #71031, Bowling Green, KY 42101, USA"},{"name":"Model Laboratory School, 521 Lancaster Ave, Richmond, KY 40475, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-7996-8661","authenticated-orcid":false,"given":"Jiwoo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Kentucky, Lexington, KY 40506, USA"},{"name":"The Gatton Academy, 1906 College Heights Blvd. #71031, Bowling Green, KY 42101, USA"},{"name":"Model Laboratory School, 521 Lancaster Ave, Richmond, KY 40475, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7234-4361","authenticated-orcid":false,"given":"Robin L.","family":"Cooper","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Kentucky, Lexington, KY 40506, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,11]]},"reference":[{"key":"ref_1","unstructured":"Alberts, B., Johnson, A., and Lewis, J. (2002). Ion Channels and the Electrical Properties of Membranes. Molecular Biology of the Cell, Garland Science. [4th ed.]."},{"key":"ref_2","unstructured":"John, G., Nicholls, A., Robert, M., and Bruce, G.W. (1992). From Neuron to Brain. A Cellular and Molecular Approach to the Function of the Nervous System, Sinauer Associates, Inc.. [3rd ed.]."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4154","DOI":"10.1073\/pnas.96.7.4154","article-title":"Calcium block of Na+ channels and its effect on closing rate","volume":"96","author":"Armstrong","year":"1999","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Prelic, S., Pal Mahadevan, V., Venkateswaran, V., Lavista-Llanos, S., Hansson, B.S., and Wicher, D. (2022). Functional interaction between Drosophila olfactory sensory neurons and their support cells. Front. Cell. Neurosci., 15.","DOI":"10.3389\/fncel.2021.789086"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"809","DOI":"10.1146\/annurev.physiol.61.1.809","article-title":"Mechanisms of hair cell tuning","volume":"61","author":"Fettiplace","year":"1999","journal-title":"Annu. Rev. Physiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1007\/s109-1998-8100-0","article-title":"Sequence and function of the two P domain potassium channels: Implications of an emerging superfamily","volume":"76","author":"Goldstein","year":"1998","journal-title":"J. Mol. Med."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Zheng, J., and Trudeau, M.C. (2015). Two-pore domain potassium channels. Handbook of Ion Channels, CRC Press. [1st ed.].","DOI":"10.1201\/b18027"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1152\/physrev.00014.2022","article-title":"New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN","volume":"104","author":"Monteil","year":"2024","journal-title":"Physiol. Rev."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1515\/zpch-1888-0274","article-title":"Zur Kinetik der L\u00f6sung befindlichen K\u00f6rper: Theorie der Diffusion","volume":"3","author":"Nernst","year":"1888","journal-title":"Z. Phys. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1515\/zpch-1889-0412","article-title":"Die elektromotorische Wirksamkeit der Jonen","volume":"4","author":"Nernst","year":"1889","journal-title":"Z. Phys. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1085\/jgp.27.1.37","article-title":"Potential, impedance, and rectification in membranes","volume":"27","author":"Goldman","year":"1943","journal-title":"J. Gen. Physiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"500","DOI":"10.1113\/jphysiol.1952.sp004764","article-title":"A quantitative description of membrane current and its application to conduction and excitation in nerve","volume":"117","author":"Hodgkin","year":"1952","journal-title":"J. Physiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1113\/jphysiol.1952.sp004716","article-title":"Measurement of current-voltage relations in the membrane of the giant axon of Loligo","volume":"116","author":"Hodgkin","year":"1952","journal-title":"J. Physiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1113\/jphysiol.1949.sp004310","article-title":"The effect of sodium ions on the electrical activity of the giant axon of the squid","volume":"108","author":"Hodgkin","year":"1949","journal-title":"J. Physiol."},{"key":"ref_15","unstructured":"Hille, B. (1992). Ionic Channels of Excitable Membranes, Sinauer Associates, Inc.. [2nd ed.]."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2185","DOI":"10.1126\/science.287.5461.2185","article-title":"The genome sequence of Drosophila melanogaster","volume":"287","author":"Adams","year":"2000","journal-title":"Science"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/S0896-6273(00)81135-6","article-title":"Ion channels and synaptic organization: Analysis of the Drosophila genome","volume":"26","author":"Littleton","year":"2000","journal-title":"Neuron"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Hadjisavva, M.E., and Cooper, R.L. (2025). The biphasic effect of lipopolysaccharide on membrane potential. Membranes, 15.","DOI":"10.3390\/membranes15030074"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Elliott, E.R., and Cooper, R.L. (2024). The effect of calcium ions on resting membrane potential. Biology, 13.","DOI":"10.3390\/biology13090750"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Hana, A., Kim, Y., Bidros, J., Neglia, K., and Cooper, R.L. (2026). Do magnesium ions have similar effects as calcium ions on resting membrane potential?. Membranes, 16.","DOI":"10.3390\/membranes16030093"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"eaaz3154","DOI":"10.1126\/sciadv.aaz3154","article-title":"The NALCN channel complex is voltage sensitive and directly modulated by extracellular calcium","volume":"6","author":"Chua","year":"2020","journal-title":"Sci. Adv."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Moose, D.L., Haase, S.J., Aldrich, B.T., and Lear, B.C. (2017). The narrow abdomen ion channel complex is highly stable and persists from development into adult stages to promote behavioral rhythmicity. Front. Cell. Neurosci., 11.","DOI":"10.3389\/fncel.2017.00159"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1069","DOI":"10.1016\/j.neuron.2013.01.018","article-title":"NLF-1 delivers a sodium leak channel to regulate neuronal excitability and modulate rhythmic locomotion","volume":"77","author":"Xie","year":"2013","journal-title":"Neuron"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"836","DOI":"10.1016\/j.cell.2015.07.036","article-title":"A conserved bicycle model for circadian clock control of membrane excitability","volume":"162","author":"Flourakis","year":"2015","journal-title":"Cell"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Ghezzi, A., Liebeskind, B.J., Thompson, A., Atkinson, N.S., and Zakon, H.H. (2014). Ancient association between cation leak channels and Mid1 proteins is conserved in fungi and animals. Front. Mol. Neurosci., 7.","DOI":"10.3389\/fnmol.2014.00015"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1002\/jcp.1040930309","article-title":"Development of action potential in larval muscle fibers in Drosophila melanogaster","volume":"93","author":"Suzuki","year":"1977","journal-title":"J. Cell. Physiol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2626","DOI":"10.1523\/JNEUROSCI.05-10-02626.1985","article-title":"Voltage clamp analysis of membrane currents in larval muscle fibers of Drosophila: Alteration of potassium currents in Shaker mutants","volume":"5","author":"Wu","year":"1985","journal-title":"J. Neurosci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"65","DOI":"10.33594\/000000338","article-title":"Pathophysiological role of K2P channels in human diseases","volume":"55","author":"Lee","year":"2021","journal-title":"Cell. Physiol. Biochem."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Williams, S., Bateman, A., and O\u2019Kelly, I. (2013). Altered expression of two-pore domain potassium (K2P) channels in cancer. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0074589"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Cochet-Bissuel, M., Lory, P., and Monteil, A. (2014). The sodium leak channel, NALCN, in health and disease. Front. Cell. Neurosci., 8.","DOI":"10.3389\/fncel.2014.00132"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"bcr2012007098","DOI":"10.1136\/bcr-2012-007098","article-title":"Chvostek\u2019s sign: A video demonstration","volume":"2012","author":"Kamalanathan","year":"2012","journal-title":"BMJ Case Rep."},{"key":"ref_32","unstructured":"Patel, M., and Hu, E.W. (2024, June 26). Trousseau Sign, StatPearls, Available online: https:\/\/pubmed.ncbi.nlm.nih.gov\/32491764\/."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"353","DOI":"10.3390\/neurosci2040026","article-title":"The effect of calcium ions on mechanosensation and neuronal activity in proprioceptive neurons","volume":"2","author":"Atkins","year":"2021","journal-title":"NeuroSci"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1016\/S0896-6273(00)80196-8","article-title":"Regulation of synapse structure and function by the Drosophila tumor suppressor gene dlg","volume":"17","author":"Budnik","year":"1996","journal-title":"Neuron"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"436","DOI":"10.1242\/dev.097758","article-title":"Postsynaptic glutamate receptors regulate local BMP signaling at the Drosophila neuromuscular junction","volume":"141","author":"Sulkowski","year":"2014","journal-title":"Development"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"45","DOI":"10.3923\/jpt.2025.45.66","article-title":"Effects of altered K2p, Mid1 and NALCN expression on membrane potential during exposure to various extracellular K+ concentrations","volume":"20","author":"Elliott","year":"2025","journal-title":"J. Pharmacol. Toxicol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1007\/BF00215114","article-title":"Improved stability of Drosophila larval neuromuscular preparation in haemolymph-like physiological solutions","volume":"175","author":"Stewart","year":"1994","journal-title":"J. Comp. Physiol. A"},{"key":"ref_38","unstructured":"Bidros, J., Brock, K., Gard, J., and Cooper, R. (2024). The effect of magnesium concentration on myogenic cardiac function: Larval Drosophila. Micropubl. Biol."},{"key":"ref_39","unstructured":"Kim, Y., Kim, J., Womack, E., and Cooper, R.L. (2025). STEM Activities for Students & Teachers: Membrane Potential, Simulations, & Invertebrate Behaviors, Azalea Art Press."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"304","DOI":"10.1016\/j.jinsphys.2009.11.002","article-title":"The resting membrane potential of Drosophila melanogaster larval muscle depends strongly on external calcium concentration","volume":"56","author":"Krans","year":"2010","journal-title":"J. Insect Physiol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1038\/259489a0","article-title":"Synaptic transmission reversibly conditioned by single-gene mutation in Drosophila melanogaster","volume":"259","author":"Ikeda","year":"1976","journal-title":"Nature"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1113\/jphysiol.1983.sp014649","article-title":"Ion currents in Drosophila flight muscles","volume":"337","author":"Salkoff","year":"1983","journal-title":"J. Physiol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1002\/cne.903500310","article-title":"Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila","volume":"350","author":"Kurdyak","year":"1994","journal-title":"J. Comp. Neurol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"546","DOI":"10.1016\/j.cbpc.2009.08.002","article-title":"Furthering pharmacological and physiological assessment of the glutamatergic receptors at the Drosophila neuromuscular junction","volume":"150","author":"Lee","year":"2009","journal-title":"Comp. Biochem. Physiol. C Toxicol. Pharmacol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1831","DOI":"10.1016\/j.cub.2012.07.063","article-title":"Integration of a retrograde signal during synapse formation by glia-secreted TGF-\u03b2 ligand","volume":"22","author":"Ashley","year":"2012","journal-title":"Curr. Biol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"895","DOI":"10.1002\/dneu.22731","article-title":"Target-dependent retrograde signaling mediates synaptic plasticity at the Drosophila neuromuscular junction","volume":"79","author":"Berke","year":"2020","journal-title":"Dev. Neurobiol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1016\/j.neuron.2015.10.011","article-title":"Phosphorylation of complexin by PKA regulates activity-dependent spontaneous neurotransmitter release and structural synaptic plasticity","volume":"88","author":"Cho","year":"2015","journal-title":"Neuron"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"e2502997122","DOI":"10.1073\/pnas.2502997122","article-title":"Nonionic signaling rapidly remodels postsynaptic DLG to induce retrograde homeostatic plasticity","volume":"122","author":"Qiu","year":"2025","journal-title":"Proc. Natl. Acad. Sci. USA"}],"container-title":["Membranes"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0375\/16\/9\/298\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T17:21:18Z","timestamp":1789147278000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0375\/16\/9\/298"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,11]]},"references-count":48,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["membranes16090298"],"URL":"https:\/\/doi.org\/10.3390\/membranes16090298","relation":{},"ISSN":["2077-0375"],"issn-type":[{"value":"2077-0375","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,11]]}}}