Developmental expression of NCS-1 (frequenin), a regulator of Kv4 K+ channels, in mouse heart

Pediatr Res. 2003 Apr;53(4):554-7. doi: 10.1203/01.PDR.0000057203.72435.C9. Epub 2003 Feb 20.

Abstract

The channel proteins responsible for the cardiac transient outward K+ current (Ito) of human and rodent heart are composed, in part, of pore-forming Kv4.3 or Kv4.2 principal subunits. Recent reports implicate K+ channel interacting proteins (members of the neuronal Ca2+-binding protein family) as subunits of the Ito channel complex. We reported that another Ca2+-binding protein, frequenin [or neuronal calcium center protein-1 (NCS-1)], also functions as a Kv4 auxiliary subunit in the brain. By examining cardiac expression of NCS-1, the aim of this study was to examine the potential physiologic relevance of this protein as an additional regulator of cardiac Ito. Immunoblot analysis demonstrates NCS-1 protein to be expressed in adult mouse ventricle at levels comparable to that found in some brain regions. Cardiac NCS-1 protein expression levels are much higher in fetal and neonatal mouse hearts when compared with the adult. Immunocytochemical analysis of isolated neonatal mouse ventricular myocytes demonstrates co-localization of NCS-1 and Kv4.2 proteins at the sarcolemma. Given its high levels of expression in the heart, NCS-1 should be considered an important potential Kv4 regulatory subunit, particularly in the immature heart.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium-Binding Proteins / genetics*
  • Calcium-Binding Proteins / metabolism*
  • Fetus
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Developmental
  • Heart / embryology*
  • Heart / physiology*
  • Heart Ventricles / metabolism
  • Mice
  • Myocardium / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neuronal Calcium-Sensor Proteins
  • Neuropeptides / genetics*
  • Neuropeptides / metabolism*
  • Potassium Channels / metabolism*
  • Potassium Channels, Voltage-Gated*
  • Shal Potassium Channels

Substances

  • Calcium-Binding Proteins
  • Kcnd2 protein, mouse
  • Nerve Tissue Proteins
  • Neuronal Calcium-Sensor Proteins
  • Neuropeptides
  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Shal Potassium Channels
  • frequenin calcium sensor proteins