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J. Mol. Sci.","IJMS"],"abstract":"<jats:p>The automaticity of human-induced Pluripotent Stem Cell-derived cardiomyocytes (hiPSC-CMs) is governed by coupled Ca2+ and membrane clocks, coordinated through local Ca2+ releases (LCRs) and cyclic adenosine monophosphate (cAMP)\/protein kinase A (PKA) signaling. We investigated the role of PKA in hiPSC-CM energetics by measuring its dynamics in the cytosol and mitochondria, and its crosstalk with Ca2+. We tested three hypotheses: (i) Ca2+-activated PKA signaling regulates energy balance; (ii) adenylyl cyclase activity correlates with spontaneous beating; and (iii) PKA compartmentalization is Ca2+-dependent. We also compared hiPSC-CMs with rabbit sinoatrial node cells (SANCs). The key findings are: (i) PKA inhibition (H-89), Ca2+ chelation (BAPTA), or mitochondrial Ca2+ blockade (Ru360) led to energy imbalance; (ii) H-89 induced compartmentalized PKA activity in the cytosol, mitochondrial matrix, and outer mitochondrial membrane; (iii) Ca2+ chelation with BAPTA reduced PKA activity globally; and (iv) PKA dynamics and Ca2+-dependent regulation were similar in hiPSC-CMs and rabbit SANCs. In conclusion, intracellular Ca2+-mediated PKA compartmentalization is present in hiPSC-CMs and rabbit SANCs.<\/jats:p>","DOI":"10.3390\/ijms27156559","type":"journal-article","created":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T17:13:17Z","timestamp":1784826797000},"page":"6559","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Intracellular Ca2+ Modulates PKA Compartmentalization and Dynamics in Human iPSC-Derived Cardiomyocytes"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-2477-0727","authenticated-orcid":false,"given":"Anat","family":"Rotschield","sequence":"first","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5982-8983","authenticated-orcid":false,"given":"Savyon","family":"Mazgaoker","sequence":"additional","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5190-5709","authenticated-orcid":false,"given":"Sofia","family":"Segal","sequence":"additional","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ido","family":"Weiser-Bitoun","sequence":"additional","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"},{"name":"Department of Internal Medicine \u201cC\u201d, Rambam Health Care Campus, Haifa 3109601, Israel"},{"name":"The Leir Clinical Research Institute at Rambam (CRIR), Rambam Health Care Campus, Haifa 3109601, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Inbar","family":"Brosh","sequence":"additional","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ofer","family":"Binah","sequence":"additional","affiliation":[{"name":"Department of Physiology, Biophysics and Systems Biology, Ruth and Bruce Rappaport Faculty of Medicine and Research Institute, Technion-IIT, Haifa 3525433, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5183-6284","authenticated-orcid":false,"given":"Yael","family":"Yaniv","sequence":"additional","affiliation":[{"name":"Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-IIT, Haifa 3200003, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"883","DOI":"10.1161\/CIRCULATIONAHA.111.045146","article-title":"Human Embryonic and Induced Pluripotent Stem Cell-Derived Cardiomyocytes Exhibit Beat Rate Variability and Power-Law Behavior","volume":"125","author":"Mandel","year":"2012","journal-title":"Circulation"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e202213153","DOI":"10.1085\/jgp.202213153","article-title":"CAMP-PKA Signaling Modulates the Automaticity of Human IPSC-Derived Cardiomyocytes","volume":"155","author":"Mazgaoker","year":"2023","journal-title":"J. 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