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Vimentin‐Ser82 as a memory phosphorylation site in astrocytes
Author(s) -
Oguri Takashi,
Inoko Akihito,
Shima Hiroshi,
Izawa Ichiro,
Arimura Nariko,
Yamaguchi Tomoya,
Inagaki Naoyuki,
Kaibuchi Kozo,
Kikuchi Kunimi,
Inagaki Masaki
Publication year - 2006
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2006.00961.x
Subject(s) - vimentin , phosphorylation , ionomycin , intermediate filament , biology , protein subunit , microbiology and biotechnology , intermediate filament protein , calmodulin , in vitro , biochemistry , cytoskeleton , immunohistochemistry , cell , immunology , gene , enzyme
In astrocytes, the PGF 2α 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, PP1cα 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.