title: CaMKII-independent effects of KN93 and its inactive analog KN92: reversible inhibition of L-type calcium channels.
abstract: Widely regarded as a specific and potent inhibitor of CaM kinases, especially CaMKII, KN93 has long been used to investigate the possible roles of CaMKII in a wide range of biological functions and systems, such as cultured cells, primary neurons, and brain slices. However, here we present evidence showing that KN93 and its structural analog KN92, which does not inhibit CaMKII, exert an unexpected, reversible, and specific reduction of currents of L-type calcium channels (CaV1.3 and CaV1.2), as compared to N-type calcium channels (CaV2.2). This effect is dependent not only on incubation time, but also on the dose of KN93 or KN92. Moreover, the effect appears to be independent of endocytosis, exocytosis, and proteasome activity. Washout and return to normal media rescues the L channel currents. Conversely, the structurally unrelated CaMKII inhibitor, AIP, fails to mimic the KN93/KN92 effect on L channel currents. Together, our data suggest that, in addition to inhibiting CaMKII, KN93 also affects CaV1.3 and CaV1.2 calcium channels in a CaMKII-independent manner.
authors.affiliation: Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Gao
authors.forename: Leslie A C
authors.initials: LA
authors.lastname: Blair
authors.forename: John
authors.initials: J
authors.lastname: Marshall
mesh_terms: D001596:Benzylamines / Q000494:pharmacology*; D020126:Brefeldin A / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000502:physiology*; D020864:Calcium Channels, N-Type / Q000235:genetics / Q000502:physiology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection; D000096926:Benzenesulfonamides
chemical_list: D001596:Benzylamines; D020126:Brefeldin A; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D007976:Leupeptins; D018942:Macrolides; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; C500545:CACNA1B protein, human; C472073:CACNA1D protein, human; C425780:KN 92; C419385:L-type calcium channel alpha(1C); C072105:KN 93; D000096926:Benzenesulfonamides; C040929:bafilomycin A1; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde