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Casein kinase II is responsible for phosphorylation of NF‐L at Ser‐473
Author(s) -
Nakamura Yu,
Hashimoto Ryota,
Kashiwagi Yujiro,
Wada Yoshinao,
Sakoda Saburo,
Miyamae Yasuyuki,
Kudo Takashi,
Takeda Masatoshi
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00832-7
Subject(s) - phosphorylation , kinase , casein kinase 2 , microbiology and biotechnology , chemistry , casein kinase 1 , protein phosphorylation , protein kinase a , cyclin dependent kinase 2 , biochemistry , biology
Ser‐473 is solely phosphorylated in vivo in the tail region of neurofilament L (NF‐L). With peptides including the native phosphorylation site, it was not possible to locate responsible kinases. We therefore adopted full‐length dephosphorylated NF‐L as the substrate, and employed MALDI/TOF (matrix‐assisted laser desorption and ionization/time of flight) mass spectrometry and a site‐specific phosphorylation‐dependent antibody recognizing Ser‐473 phosphorylation. The antibody showed that casein kinase I (CK I) as well as casein kinase II (CK II) phosphorylated Ser‐473 in vitro, while neither GSK‐3β nor calcium/calmodulin‐dependent protein kinase II did so. However, the mass spectra of the tail fragments of the phosphorylated NF‐L indicated that CK II was the kinase mediating Ser‐473 phosphorylation in vitro as opposed to CK I, because CK I phosphorylated another site as well as Ser‐473 in vitro. The antibody also demonstrated that NF‐L phosphorylated at Ser‐473 was abundant in the neuronal perikarya of the rat cortex, indicating that phosphorylation of Ser‐473 may take place there. This result may support the suggestion that CK II is the kinase responsible for Ser‐473 phosphorylation. Despite many reports showing that CK I mediates phosphorylation of neurofilaments, CK II may phosphorylate NF‐L in vivo.