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Differential Cellular Phosphorylation of Neurofilament Heavy Side‐Arms by Glycogen Synthase Kinase‐3 and Cyclin‐Dependent Kinase‐5
Author(s) -
Guidato Sonia,
Tsai LiHuei,
Woodgett Jim,
Miller Christopher C. J.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66041698.x
Subject(s) - cyclin dependent kinase , phosphorylation , gsk 3 , kinase , neurofilament , glycogen synthase , gsk3b , microbiology and biotechnology , biology , transfection , biochemistry , cyclin dependent kinase 5 , protein subunit , cyclin dependent kinase 2 , chemistry , protein kinase a , cell cycle , cell , immunology , immunohistochemistry , gene
To investigate the cellular mechanisms regulating neurofilament‐heavy subunit (NF‐H) side‐arm phosphorylation, we studied the ability of three putative neurofilament kinases, glycogen synthase kinase‐3 (GSK‐3)α, GSK‐3β, and cyclin‐dependent kinase‐5 (cdk‐5), to phosphorylate NF‐H in transfected cells. We analysed NF‐H phosphorylation by using a panel of phosphorylation‐dependent antibodies and also by monitoring the electrophoretic mobility of the transfected NF‐H on sodium dodecyl sulphate‐polyacrylamide gel electrophoresis because this is known to be affected by side‐arm phosphorylation. Our results demonstrate that whereas GSK‐3α, GSK‐3β, and cdk‐5 will all phosphorylate NF‐H, they generate different antibody reactivity profiles. GSK‐3α and GSK‐3β induce a partial retardation of a proportion of the transfected NF‐H, but only cdk‐5 alters the rate of electrophoretic migration to that of NF‐H from brain. We conclude that cdk‐5 and GSK‐3 phosphorylate different residues or sets of residues within NF‐H sidearms in cells. We further show that cdk‐5 is active in both the CNS and the PNS but that this activity is not dependent on expression of its activator, p35. This suggests that there are other activators of cdk‐5.