S100B-Mediated Inhibition of the Phosphorylation of GFAP Is Prevented by TRTK-12

Juliana Karl Frizzo*, Francine Tramontina, Erica Bortoli, Carmen Gottfried, Rodrigo B. Leal, Imre Lengyel, Rosario Donato, Peter R. Dunkley, Carlos Alberto Gonçalves

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


S100B belongs to a family of calcium-binding proteins involved in cell cycle and cytoskeleton regulation. We observed an inhibitory effect of S100B on glial fibrillary acidic protein (GFAP) phosphorylation, when stimulated by cAMP or Ca 2+/calmodulin, in a cytoskeletal fraction from primary astrocyte cultures. We found that S100B has no direct effect on CaM KII activity, the major kinase in this cytoskeletal fraction able to phosphorylate GFAP. The inhibition of GFAP phosphorylation is most likely due to the binding of S100B to the phosphorylation sites on this protein and blocking the access of these sites to the protein kinases. This inhibition was dependent on Ca 2+. However, Zn 2+ could substitute for Ca 2+. The inhibitory effect of S100B was prevented by TRTK-12, a peptide that blocks S100B interaction with several target proteins including glial fibrillary acidic protein. These data suggest a role for S100B in the assembly of intermediate filaments in astrocytes.

Original languageEnglish
Pages (from-to)735-740
Number of pages6
JournalNeurochemical Research
Issue number4
Publication statusPublished - Apr 2004
Externally publishedYes


  • Astrocytes
  • Ca
  • GFAP phosphorylation
  • S100B
  • Zn

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry


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