TY - JOUR
T1 - Reversible Inhibition of Calcineurin by the Polyphenolic Aldehyde Gossypol
AU - Baumgrass, Ria
AU - Weiwad, Matthias
AU - Erdmann, Frank
AU - Liu, Jun O.
AU - Wunderlich, Dirk
AU - Grabley, Susanne
AU - Fischer, Gunter
PY - 2001/12/21
Y1 - 2001/12/21
N2 - The reversible inhibition of calcineurin (CAN)(CaN), which is the only Ca2+/calmodulin-dependent protein Ser/Thr phosphatase, is thought to be a key functional event for most cyclosporin A (CsA)- and tacrolimus (FK506)-mediated biological effects. In addition to CaN inhibition, however, CsA and FK506 have multiple biochemical effects because of their action in a gain-of-function model that requires prior binding to immunophilic proteins. We screened a small molecule library for direct inhibitors of CaN using CaN-mediated dephosphorylation of 33P-labeled 19-residue phosphopeptide substrate (RII phosphopeptide) as an assay and found the polyphenolic aldehyde gossypol to be a novel CaN inhibitor. Unlike CsA and FK506, gossypol does not require a matchmaker protein for reversible CaN inhibition with an IC50 value of 15 μM. Gossypolone, a gossypol analog, showed improved inhibition of both RII phosphopeptide and p-nitrophenyl phosphate dephosphorylation with an IC50 of 9 and 6 μM, respectively. In contrast, apogossypol hexaacetate was inactive. Gossypol acts noncompetitively, interfering with the binding site for the cyclophilin 18-CsA complex in CaN. In contrast to CsA and FK506, gossypol does not inactivate the peptidyl-prolyl-cis/trans-isomerase activity of immunophilins. Similar to CsA and FK506, T cell receptor signaling induced by phorbol 12-myristate 13-acetate/ionomycin is inhibited by gossypol in a dose-dependent manner, demonstrated by the inhibition of nuclear factor of activated T cell (NFAT) cl translocation from the cytosol into the nucleus and suppression of NFAT-luciferase reporter gene activity.
AB - The reversible inhibition of calcineurin (CAN)(CaN), which is the only Ca2+/calmodulin-dependent protein Ser/Thr phosphatase, is thought to be a key functional event for most cyclosporin A (CsA)- and tacrolimus (FK506)-mediated biological effects. In addition to CaN inhibition, however, CsA and FK506 have multiple biochemical effects because of their action in a gain-of-function model that requires prior binding to immunophilic proteins. We screened a small molecule library for direct inhibitors of CaN using CaN-mediated dephosphorylation of 33P-labeled 19-residue phosphopeptide substrate (RII phosphopeptide) as an assay and found the polyphenolic aldehyde gossypol to be a novel CaN inhibitor. Unlike CsA and FK506, gossypol does not require a matchmaker protein for reversible CaN inhibition with an IC50 value of 15 μM. Gossypolone, a gossypol analog, showed improved inhibition of both RII phosphopeptide and p-nitrophenyl phosphate dephosphorylation with an IC50 of 9 and 6 μM, respectively. In contrast, apogossypol hexaacetate was inactive. Gossypol acts noncompetitively, interfering with the binding site for the cyclophilin 18-CsA complex in CaN. In contrast to CsA and FK506, gossypol does not inactivate the peptidyl-prolyl-cis/trans-isomerase activity of immunophilins. Similar to CsA and FK506, T cell receptor signaling induced by phorbol 12-myristate 13-acetate/ionomycin is inhibited by gossypol in a dose-dependent manner, demonstrated by the inhibition of nuclear factor of activated T cell (NFAT) cl translocation from the cytosol into the nucleus and suppression of NFAT-luciferase reporter gene activity.
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U2 - 10.1074/jbc.M103273200
DO - 10.1074/jbc.M103273200
M3 - Article
C2 - 11598106
AN - SCOPUS:0035930554
SN - 0021-9258
VL - 276
SP - 47914
EP - 47921
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 51
ER -