Specificity of blebbistatin, an inhibitor of myosin II

J Muscle Res Cell Motil. 2004;25(4-5):337-41. doi: 10.1007/s10974-004-6060-7.


Blebbistatin is a small molecule inhibitor discovered in a screen for inhibitors of nonmuscle myosin IIA. We have examined the specificity and potency of the drug by assaying its effects on the actin-activated MgATPase assay of diverse members of the myosin superfamily. Blebbistatin potently inhibits several striated muscle myosins as well as vertebrate nonmuscle myosin IIA and IIB with IC50 values ranging from 0.5 to 5 microM. Interestingly, smooth muscle which is highly homologous to vertebrate nonmuscle myosin is only poorly inhibited (IC50=80 microM). The drug potently inhibits Dictyostelium myosin II, but poorly inhibits Acanthamoeba myosin II. Blebbistatin did not inhibit representative myosin superfamily members from classes I, V, and X.

Publication types

  • Comparative Study

MeSH terms

  • Actins / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Animals
  • Fluorescent Dyes / chemistry
  • Heterocyclic Compounds, 4 or More Rings / pharmacology*
  • Humans
  • Myosin Type II / antagonists & inhibitors*
  • Myosin Type II / metabolism
  • Myosins / antagonists & inhibitors
  • Myosins / metabolism


  • Actins
  • Fluorescent Dyes
  • Heterocyclic Compounds, 4 or More Rings
  • blebbistatin
  • Adenosine Triphosphate
  • Myosin Type II
  • Myosins