Interaction of DPP10a with Kv4.3 channel complex results in a sustained current component of human transient outward current Ito

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • K. Turnow - , Technische Universität Dresden (Autor:in)
  • K. Metzner - , Technische Universität Dresden, Universität Leipzig (Autor:in)
  • D. Cotella - , University of Eastern Piedmont (Autor:in)
  • M. J. Morales - , State University of New York (SUNY) at Buffalo (Autor:in)
  • M. Schaefer - , Universität Leipzig (Autor:in)
  • T. Christ - , Universitätsklinikum Hamburg-Eppendorf (UKE) (Autor:in)
  • U. Ravens - , Technische Universität Dresden (Autor:in)
  • E. Wettwer - , Technische Universität Dresden (Autor:in)
  • S. Kämmerer - , Universität Leipzig (Autor:in)

Abstract

The sustained component of the K+ outward current in human atrial myocytes is believed to be due to the slowly inactivating ultra-rapid potassium current IKur and not to the fast inactivating transient outward current Ito. Here we provide evidence for contribution of Ito to this late current due to the effects of dipeptidyl peptidase-like protein (DPP) 10 (DPP10a) interacting with Kv4.3 channels. We studied the late current component of Ito in human atrial myocytes and CHO cells co-expressing Kv4.3 or Kv4.3/KChIP2 (control) and DPP proteins using voltage-clamp technique and a pharmacological approach. A voltage dependent and slowly inactivating late current (43 % of peak amplitude) could be observed in atrial myocytes. We found a similar current in CHO cells expressing Kv4.3/KChIP2 + DPP10a, but not in cells co-expressing Kv4.3 + DPP or Kv4.3/KChIP2 + DPP6-S. Assuming that DPP10a influences atrial Ito, we detected DPP10 expression of three alternatively spliced mRNAs, DPP10 protein and colocalization of Kv4.3 and DPP10 proteins in human atrial myocytes. DPP10a did not affect properties of expressed Kv1.5 excluding a contribution to the sustained IKur in atrial cells. To test for the contribution of Kv4-based Ito on sustained K+ outward currents in human atrial myocytes, we used 4-AP to block IKur, in combination with Heteropoda toxin 2 to block Kv4 channels. We could clearly separate an Ito fraction of about 19 % contributing to the late current in atrial myocytes. Thus, the interaction of DPP10a, expressed in human atrium, with Kv4.3 channels generates a sustained current component of Ito, which may affect late repolarization phase of atrial action potentials.

Details

OriginalspracheEnglisch
Aufsatznummer5
Seitenumfang13
FachzeitschriftBasic Research in Cardiology
Jahrgang110
Ausgabenummer2
PublikationsstatusVeröffentlicht - März 2015
Peer-Review-StatusJa

Externe IDs

PubMed 601499773
researchoutputwizard legacy.publication#67449
Scopus 84928243533
ORCID /0009-0008-1895-4538/work/142248978

Schlagworte

Ziele für nachhaltige Entwicklung

Schlagwörter

  • DPP10a, Heteropoda toxin 2, Human atrium, K outward current, Kv4.3 channel, Transient outward current