{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T15:12:22Z","timestamp":1781104342396,"version":"3.54.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"6","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1993,3,15]]},"abstract":"<jats:p>The elevation of Ca2+ levels in the cytoplasm inactivates inward-rectifying K+ channels that play a central role in regulating the apertures of stomatal pores in higher plants. However, the mechanism for the Ca(2+)-mediated inhibition of K(+)-channel function is unknown. Using patch-clamp techniques, we show that cyclophilin-cyclosporin A and FK506-binding protein-FK506 complexes, which are highly specific inhibitors of protein phosphatase 2B (calcineurin), block Ca(2+)-induced inactivation of K+ channels in Vicia faba guard cells. A constitutively active calcineurin fragment that is Ca(2+)-independent inhibits K(+)-channel activity in the absence of Ca2+. We have also identified an endogenous Ca(2+)-dependent phosphatase activity from V. faba that is inhibited by the cyclophilin-cyclosporin A and FK506-binding protein-FK506 complexes. Our findings implicate a Ca(2+)-dependent, calcineurin-like protein phosphatase in a Ca2+ signal-transduction pathway of higher plants.<\/jats:p>","DOI":"10.1073\/pnas.90.6.2202","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T08:41:16Z","timestamp":1149064876000},"page":"2202-2206","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":163,"title":["Immunosuppressants implicate protein phosphatase regulation of K+ channels in guard cells."],"prefix":"10.1073","volume":"90","author":[{"given":"S","family":"Luan","sequence":"first","affiliation":[{"name":"Department of Chemistry, Harvard University, Cambridge, MA 02138."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Harvard University, Cambridge, MA 02138."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F","family":"Rusnak","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Harvard University, Cambridge, MA 02138."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S M","family":"Assmann","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Harvard University, Cambridge, MA 02138."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S L","family":"Schreiber","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Harvard University, Cambridge, MA 02138."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1993,3,15]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.90.6.2202","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T13:35:24Z","timestamp":1649856924000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.90.6.2202"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,3,15]]},"references-count":0,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1993,3,15]]}},"alternative-id":["10.1073\/pnas.90.6.2202"],"URL":"https:\/\/doi.org\/10.1073\/pnas.90.6.2202","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1993,3,15]]},"assertion":[{"value":"1993-03-15","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}