Site-specific phosphorylation of SCG10 in neuronal plasticity: role of Ser73 phosphorylation by N-methyl D-aspartic acid receptor activation in rat hippocampus.
Accumulated evidence suggests that actin and microtubule regulating proteins contribute to neuronal structural dynamics, which subsequently affect neuronal plasticity. SCG10 is a neuronal-specific stathmin protein with microtubule destabilizing activity that is affected by multiple phosphorylation, at least in vitro. SCG10 has four major phosphorylation sites: Ser50 and Ser97 targeted by protein kinase A (PKA), and Ser62 and Ser73 targeted by mitogen-activated protein kinase (MAPK). To explore the potential roles of site-specific phosphorylation in physiological models, we developed phosphorylation site-specific antibodies and examined the SCG10 status in primary cultured hippocampal neurons and tissues. Although SCG10 is concentrated in growth cones and the Golgi apparatus in primary cultured neurons, the phosphorylated form was also detected in both regions, suggesting that MT dynamics within the growth cone may be regulated by protein phosphorylation. In the adult hippocampus, an intense stimulus such as kainate treatment induced a rapid phosphorylation of Ser73 within 15 min that was sustained for at least 60 min. This response was mediated through the N-methyl D-aspartic acid (NMDA) receptor and was ablated by the antagonist MK-801. The MAPK enzyme Erk2 was simultaneously activated along a similar time course to SCG10, suggesting that Erk2 may directly phosphorylate Ser73. These results demonstrate that changes in the phosphorylation status of SCG10 in vivo, dependent upon neural activity and/or plasticity, could affect the microtubule dynamics in neuronal dendrites.
Morii
Hiroshi
H
Department of Molecular Genetics, National Institute for Longevity Sciences, 36-3 Gengo, Morioka, Oobu, 474-8522, Japan.
Yamada
Tomiko
T
Nakano
Itsuko
I
Coulson
Judy M
JM
Mori
Nozomu
N
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins; D002478:Cells, Cultured; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005455:Fluorescent Antibody Technique / Q000379:methods; D006624:Hippocampus / Q000166:cytology*; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D008565:Membrane Proteins; D008868:Microtubule Proteins; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008954:Models, Biological; D009414:Nerve Growth Factors / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010433:Pentylenetetrazole / Q000494:pharmacology; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D013997:Time Factors
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D008565:Membrane Proteins; D008868:Microtubule Proteins; D009414:Nerve Growth Factors; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; C512848:Stmn2 protein, rat; D012694:Serine; D016291:Dizocilpine Maleate; D020929:Mitogen-Activated Protein Kinase Kinases; D007608:Kainic Acid; D010433:Pentylenetetrazole