TY - JOUR
T1 - S100B-Mediated Inhibition of the Phosphorylation of GFAP Is Prevented by TRTK-12
AU - Frizzo, Juliana Karl
AU - Tramontina, Francine
AU - Bortoli, Erica
AU - Gottfried, Carmen
AU - Leal, Rodrigo B.
AU - Lengyel, Imre
AU - Donato, Rosario
AU - Dunkley, Peter R.
AU - Gonçalves, Carlos Alberto
PY - 2004/4
Y1 - 2004/4
N2 - 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.
AB - 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.
KW - Astrocytes
KW - Ca
KW - GFAP phosphorylation
KW - S100B
KW - Zn
UR - http://www.scopus.com/inward/record.url?scp=1842560240&partnerID=8YFLogxK
U2 - 10.1023/B:NERE.0000018844.51009.40
DO - 10.1023/B:NERE.0000018844.51009.40
M3 - Article
C2 - 15098935
AN - SCOPUS:1842560240
SN - 0364-3190
VL - 29
SP - 735
EP - 740
JO - Neurochemical Research
JF - Neurochemical Research
IS - 4
ER -