Dephosphorylation of microtubule-associated protein 2, tau factor, and tubulin by calcineurin

J Neurochem. 1985 Jul;45(1):276-83. doi: 10.1111/j.1471-4159.1985.tb05504.x.


Calcineurin dephosphorylated microtubule-associated protein 2 (MAP2) and tau factor phosphorylated by cyclic AMP-dependent and Ca2+, calmodulin-dependent protein kinases from the brain. Tubulin, only phosphorylated by the Ca2+, calmodulin-dependent protein kinase, served as substrate for calcineurin. The concentrations of calmodulin required to give half-maximal activation of calcineurin were 21 and 16 nM with MAP2 and tau factor as substrates, respectively. The Km and Vmax values were in ranges of 1-3 microM and 0.4-1.7 mumol/mg/min, respectively, for MAP2 and tau factor. The Km value for tubulin was in a similar range, but the Vmax value was lower. The peptide map analysis revealed that calcineurin dephosphorylated MAP2 and tau factor universally, but not in a site-specific manner. The autophosphorylated Ca2+, calmodulin-dependent protein kinase was not dephosphorylated by calcineurin. These results suggest that calcineurin plays an important role in the functions of microtubules via dephosphorylation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Calcium / pharmacology
  • Calmodulin / pharmacology
  • Calmodulin-Binding Proteins
  • Cations, Divalent
  • Cattle
  • Cyclic AMP / pharmacology
  • DNA Polymerase III
  • Kinetics
  • Microtubule-Associated Proteins / metabolism*
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Protein Kinases / metabolism
  • Rats
  • Transcription Factors / metabolism*
  • Tubulin / metabolism*


  • Calmodulin
  • Calmodulin-Binding Proteins
  • Cations, Divalent
  • Microtubule-Associated Proteins
  • Phosphoproteins
  • Transcription Factors
  • Tubulin
  • Cyclic AMP
  • Protein Kinases
  • transcription factor tau
  • DNA Polymerase III
  • Phosphoprotein Phosphatases
  • Calcium