Vimentin‐Ser82 as a memory phosphorylation site in astrocytes
Vimentin‐Ser82 as a memory phosphorylation site in astrocytes
复制标题
DOI：
10.1111/j.1365-2443.2006.00961.x
复制
发表时间：
2006-05
期刊：
影响因子：
2.1
通讯作者：
Takashi Oguri;Akihito Inoko;H. Shima;I. Izawa;N. Arimura;Tomoya Yamaguchi;N. Inagaki;K. Kaibuchi;K. Kikuchi;M. Inagaki
中科院分区：
文献类型：
--
作者：
Takashi Oguri;Akihito Inoko;H. Shima;I. Izawa;N. Arimura;Tomoya Yamaguchi;N. Inagaki;K. Kaibuchi;K. Kikuchi;M. Inagaki
在星形胶质细胞中，PGF 2 α或离子霉素处理通过Ca 2 +/钙调蛋白依赖性蛋白激酶II（CaMKII）诱导波形蛋白（一种III型中间丝）的Ser 38和Ser 82磷酸化。我们发现波形蛋白磷酸化丝氨酸82的去磷酸化速度比磷酸化丝氨酸38慢得多。波形蛋白磷酸丝氨酸38在体外被纯化的PP 1催化亚基（PP 1c）快速脱磷酸化，而磷酸丝氨酸82对PP 1c不敏感。由于PP 1c通过一个APF基序（Val 83-Asp 84-Phe 85）直接与波形蛋白结合，因此PP 1c活性位点似乎无法接近磷酸化丝氨酸82，导致丝氨酸82磷酸化时间延长。在星形胶质细胞中，PP 1c α在体内与波形蛋白丝相关。离子霉素在短时间内的重复处理导致Ser 82磷酸化的持续升高，导致波形蛋白丝的显著分解。综上所述，这些结果表明，波形蛋白是星形胶质细胞中PP 1c结合伴侣的新成员，波形蛋白-Ser 82可能作为记忆磷酸化位点。
In astrocytes, the PGF2α or ionomycin treatment induces the phosphorylation at Ser38 and Ser82 of vimentin, a type III intermediate filament, by Ca2+/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.