{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T16:36:27Z","timestamp":1781109387193,"version":"3.54.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"2","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1985,1]]},"abstract":"<jats:p>A brain cytoskeletal preparation that is highly enriched in calmodulin-dependent protein kinase facilitated the study of the binding of 125I-labeled calmodulin to the native enzyme. The binding was specific, saturable, Ca2+-dependent, and inhibited by trifluoperazine. Stoichiometric analysis revealed that the ratio of bound calmodulin to the alpha subunit of the protein kinase was about 1:10 (+\/-30%), indicating that in the native state not all of the enzyme subunits were accessible to bind calmodulin. The Kd for the binding reaction was 7 X 10(-9) M and was subject to regulation by divalent cations other than Ca2+, decreasing to 1.7 X 10(-9) M in the presence of 7 mM MgCl2. Activation of the protein kinase in the presence of Ca2+ and calmodulin resulted in marked autophosphorylation of the enzyme subunits. The autophosphorylation was accompanied by a 2-fold decrease in the affinity and number of 125I-labeled calmodulin binding sites. This effect was also reflected by an increase in the apparent Km for Ca2+ from 90 to 200 X 10(-9) M. Thus, enzyme autophosphorylation appears to represent a negative feedback signal, rendering the enzyme less sensitive to subsequent stimulation by physiologic increases in the intracellular Ca2+ concentration. These results help to clarify the mode of neuronal intracellular Ca2+ signaling.<\/jats:p>","DOI":"10.1073\/pnas.82.2.287","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T05:47:31Z","timestamp":1149054451000},"page":"287-291","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":36,"title":["Calmodulin binding to the cytoskeletal neuronal calmodulin-dependent protein kinase is regulated by autophosphorylation."],"prefix":"10.1073","volume":"82","author":[{"suffix":"3rd","given":"H","family":"LeVine","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N E","family":"Sahyoun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P","family":"Cuatrecasas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1985,1]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.82.2.287","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T12:18:23Z","timestamp":1649852303000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.82.2.287"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1985,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1985,1]]}},"alternative-id":["10.1073\/pnas.82.2.287"],"URL":"https:\/\/doi.org\/10.1073\/pnas.82.2.287","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1985,1]]},"assertion":[{"value":"1985-01-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}