Calmodulin is a calcium-
dependent protein that regulates the activity of a diverse array of enzymes, ion channels, and other proteins and thus has diverse roles in cell function.
1,2 W-
7 is a cell-
permeable antagonist of calmodulin (K
i = 11 μM).
3,4 Two molecules of W-
7 bind to calcium-
binding domains in each calmodulin molecule, blocking its interaction with target proteins.
3 W-
7 also associates, at lower affinities, with calcium-
binding domains of other proteins, including troponin C and myosin light chain kinase (K
i = 70 and 300 μM, respectively).
5,6,7