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Acta Physiologica 2011; Volume 202, Supplement 684
The Joint Conference (FAMÉ 2011) of the LXXVth Meeting of the Hungarian Physiological Society, XVIth Meeting of the Hungarian Society of Anatomists, Experimental Section of the Hungarian Society for Experimental and Clinical Pharmacology and Hungarian Society for Microcirculation and Vascular Biology
6/8/2011-6/11/2011
Pécs, Hungary
SURFACE EXPRESSION OF KV ION CHANNELS ARE MODULATED BY SAP97 IN DILATED CARDIOMYOPATHY
Abstract number: P82
Szuts1 V., Varga-Orvos2 Z., Menesi2 D., Houshmand1 N., Sarnyai1,3 F., Jost1,4 N., Virag1 L., Baczko1 I., Deak3 F., Kiss3 I., Puskas2 L. G., Papp1,4 G. J., Varro1 A.
Aims:
The synapse-associated protein 97 (SAP97) is a member of the MAGUK family, anchors the Kv type ion channels at the plasma membrane (PM) and regulates the subcellular localization of cardiac Kv ion channels. The aim of this study was to compare the expression and distribution of Kv channels and the SAP97 in the cardiomyocytes of failing heart.
Methods:
We investigated the expression of the Kv ion channels by real-time QPCR, immunoblotting and immunofluorescence in the ventricular preparations of failing and non-failing human hearts.
Results:
The mRNA expression for a-subunits of Kv channels changed showing mild up- or down-regulation in the patients. HERG and KvLQT1 mRNAs were slightly upregulated but gene expression for KChIP2 decrease significantly to 50% in the tissues of DCM patients versus controls. Immunostaining revealed that the protein expression of KChIP2 b-subunit decreased significantly in the samples of patients. SAP97 and both Kv4.3 and Kv4.2 channelsubunits colocalize at the PM of non-failing cardiomyocytes and the distribution of these complexes has changed in the failing heart.
Conclusion:
These data provide valuable information concerning dilated cardiomyopathy remodels the expression of transient outward and delayed rectifier potassium channel genes and proteins. Down-regulation was significant in the level of anchoring-subunits and not significant in the pore-forming a-subunits. The decreased SAP97 expression suggests that altered regulation of potassium ion channel expression may play a main role in the development of pathological cardiac repolarization in cardiomyopathy.
Support:
OTKA NI-6190, DFG, EU FP6 LSHM-CT-2005-018833, EUGeneHeart and TAMOP-4.2.2.-08/1-2008-0013
To cite this abstract, please use the following information:
Acta Physiologica 2011; Volume 202, Supplement 684 :P82