S-Nitrosylation Induces Both Autonomous Activation and Inhibition of Calcium/Calmodulin-dependent Protein Kinase II δ.

NO is known to modulate calcium handling and cellular signaling in the myocardium, but key targets for NO in the heart remain unidentified. Recent reports have implied that NO can activate calcium/calmodulin (Ca(2+)/CaM)-dependent protein kinase II (CaMKII) in neurons and the heart. Here we use our novel sensor of CaMKII activation, Camui, to monitor changes in the conformation and activation of cardiac CaMKII (CaMKIIδ) activity after treatment with the NO donor S-nitrosoglutathione (GSNO). We demonstrate that exposure to NO after Ca(2+)/CaM binding to CaMKIIδ results in autonomous kinase activation, which is abolished by mutation of the Cys-290 site. However, exposure of CaMKIIδ to GSNO prior to Ca(2+)/CaM exposure strongly suppresses kinase activation and conformational change by Ca(2+)/CaM. This NO-induced inhibition was ablated by mutation of the Cys-273 site. We found parallel effects of GSNO on CaM/CaMKIIδ binding and CaMKIIδ-dependent ryanodine receptor activation in adult cardiac myocytes. We conclude that NO can play a dual role in regulating cardiac CaMKIIδ activity

S-Nitrosylation Induces Both Autonomous Activation and Inhibition of Calcium/Calmodulin-dependent Protein Kinase II δ.

NO is known to modulate calcium handling and cellular signaling in the myocardium, but key targets for NO in the heart remain unidentified. Recent reports have implied that NO can activate calcium/calmodulin (Ca(2+)/CaM)-dependent protein kinase II (CaMKII) in neurons and the heart. Here we use our novel sensor of CaMKII activation, Camui, to monitor changes in the conformation and activation of cardiac CaMKII (CaMKIIδ) activity after treatment with the NO donor S-nitrosoglutathione (GSNO). We demonstrate that exposure to NO after Ca(2+)/CaM binding to CaMKIIδ results in autonomous kinase activation, which is abolished by mutation of the Cys-290 site. However, exposure of CaMKIIδ to GSNO prior to Ca(2+)/CaM exposure strongly suppresses kinase activation and conformational change by Ca(2+)/CaM. This NO-induced inhibition was ablated by mutation of the Cys-273 site. We found parallel effects of GSNO on CaM/CaMKIIδ binding and CaMKIIδ-dependent ryanodine receptor activation in adult cardiac myocytes. We conclude that NO can play a dual role in regulating cardiac CaMKIIδ activity

Japanese patients with Fabry disease predominantly showing cardiac and neurological manifestation with novel missense mutation : R220P

AbstractBackgroundFabry disease, an X-linked lysosomal sphingolipid storage disorder caused by mutation of the α-galactosidase A (GLA) gene, results in systemic organ damage. However, the age of onset of clinical manifestations and course of the disease are variable even within the same family.ObjectiveIn this study, we evaluated the clinical phenotype and the molecular lesions associated with the GLA gene in a Japanese family with Fabry disease that predominantly showed cardiac and neurological manifestations.MethodsA genetic analysis of the GLA gene using conventional genomic sequencing was performed in all seven members of this family, including four hemizygous males and three heterozygous females. Endomyocardial biopsy was performed in two patients with severe left ventricular (LV) hypertrophy.ResultsA novel missense mutation was identified at codon 220 in exon 5, thus resulting in an arginine to proline substitution (R220P) in all seven family members. The three adult hemizygous males had LV hypertrophy and developed neurological manifestations in their 50s. One of the adult hemizygotes developed complete atrioventricular block. On the other hand, we could not find any organ damage in a young hemizygous male or the three heterozygous females.ConclusionWe identified a novel missense mutation in a Japanese family with Fabry disease showing cardiac and neurological manifestations. In patients with Fabry disease, advanced organ damage in the heart and brain can be life-threatening, even if renal failure is lacking