Calcium-dependent interactions of an ionophore A23187 with calmodulin

Biochem Biophys Res Commun. 1985 Jul 16;130(1):200-6. doi: 10.1016/0006-291x(85)90402-4.


We found that ionophore A23187 interacted reversibly with calmodulin (CaM), in a calcium-dependent fashion. It was found that A23187 interacts selectively with CaM, among calcium binding proteins (such as troponin C and S-100 protein) and other proteins. However, apparently differing from W-7, A23187 did not suppress CaM-dependent enzyme activity such as myosin light chain kinase and Ca2+-dependent cyclic nucleotide phosphodiesterase. Our observations suggest that there are novel calcium-dependent regions of CaM which can be monitored using ionophore A23187 and may not be related to enzyme activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcimycin* / metabolism
  • Calcium
  • Calcium-Binding Proteins
  • Calmodulin* / metabolism
  • Cells, Cultured
  • Membranes / metabolism
  • Muscle, Smooth / metabolism
  • Nicardipine
  • Nifedipine / analogs & derivatives
  • Nifedipine / metabolism
  • Protein Binding
  • Proteins
  • Rabbits
  • Solubility
  • Spectrometry, Fluorescence


  • Calcium-Binding Proteins
  • Calmodulin
  • Proteins
  • Calcimycin
  • Nicardipine
  • Nifedipine
  • Calcium