Vimentin-Ser82 as a memory phosphorylation site in astrocytes

Genes Cells. 2006 May;11(5):531-40. doi: 10.1111/j.1365-2443.2006.00961.x.


In astrocytes, the PGF(2alpha) or ionomycin treatment induces the phosphorylation at Ser38 and Ser82 of vimentin, a type III intermediate filament, by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). We found here that vimentin phospho-Ser82 was dephosphorylated much slower than phospho-Ser38. Vimentin phospho-Ser38 was dephosphorylated quickly by purified PP1 catalytic subunit (PP1c) in vitro, whereas phospho-Ser82 was insensitive to PP1c. Because PP1c directly bound to vimentin through a VxF motif (Val83-Asp84-Phe85), the PP1c active site appeared to be unable to approach phospho-Ser82, leading to the prolongation of the phosphorylation at Ser-82. In astrocytes, PP1calpha was in vivo associated with vimentin filaments. The repetitive treatment by ionomycin at a short interval resulted in the sustained elevation of Ser82 phosphorylation, leading to the marked disassembly of vimentin filaments. Taken together, these results suggest that vimentin is a novel member of binding partner of PP1c in astrocytes, and vimentin-Ser82 may act as a memory phosphorylation site.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Astrocytes / cytology
  • Astrocytes / enzymology*
  • Binding Sites
  • Calcium / metabolism
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cells, Cultured
  • Dinoprost / metabolism
  • Dinoprost / pharmacology
  • Immunohistochemistry
  • Ionomycin / metabolism
  • Ionomycin / pharmacology
  • Models, Biological
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Protein Phosphatase 1
  • Protein Subunits / metabolism
  • Rats
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Serine / metabolism*
  • Time Factors
  • Vimentin / metabolism*


  • Protein Subunits
  • Recombinant Proteins
  • Vimentin
  • Serine
  • Ionomycin
  • Dinoprost
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1
  • Calcium