| Title : Interaction of DPP10a with Kv4.3 channel complex results in a sustained current component of human transient outward current I to - Turnow_2015_Basic.Res.Cardiol_110_457 |
| Author(s) : Turnow K , Metzner K , Cotella D , Morales MJ , Schaefer M , Christ T , Ravens U , Wettwer E , Kammerer S |
| Ref : Basic Res Cardiol , 110 :457 , 2015 |
| 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 I Kur and not to the fast inactivating transient outward current I to. Here we provide evidence for contribution of I to 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 I to 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 I to, 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 I Kur in atrial cells. To test for the contribution of Kv4-based I to on sustained K(+) outward currents in human atrial myocytes, we used 4-AP to block I Kur, in combination with Heteropoda toxin 2 to block Kv4 channels. We could clearly separate an I to 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 I to, which may affect late repolarization phase of atrial action potentials. |
| ESTHER : Turnow_2015_Basic.Res.Cardiol_110_457 |
| PubMedSearch : Turnow_2015_Basic.Res.Cardiol_110_457 |
| PubMedID: 25600224 |
Turnow K, Metzner K, Cotella D, Morales MJ, Schaefer M, Christ T, Ravens U, Wettwer E, Kammerer S (2015)
Interaction of DPP10a with Kv4.3 channel complex results in a sustained current component of human transient outward current I to
Basic Res Cardiol
110 :457
Turnow K, Metzner K, Cotella D, Morales MJ, Schaefer M, Christ T, Ravens U, Wettwer E, Kammerer S (2015)
Basic Res Cardiol
110 :457