Phosphorylation of neurofilament heavy chain side-arms by stress activated protein kinase-1b/Jun N-terminal kinase-3.
Neurofilaments comprise three subunit proteins; neurofilament light, middle and heavy chains (NF-L, NF-M and NF-H). The carboxy-terminal domains of NF-M and NF-H form side-arms that project from the filament and that of NF-H contains multiple repeats of the motif lys-ser-pro, the serines of which are targets for phosphorylation. The level of phosphorylation on the lys-ser-pro repeats varies topographically within the cell; in cell bodies and proximal axons, the side-arms are largely non-phosphorylated whereas in more distal regions of axons, the side-arms are heavily phosphorylated. Here we show that stress activated protein kinase 1b (SAPK1b), a major SAPK in neurones will phosphorylate NF-H side-arms both in vitro and in transfected cells. These studies suggest that SAPK1b targets multiple phosphorylation sites within NF-H side-arms. Additionally, we show that glutamate treatment induces activation of SAPK1b in primary cortical neurones and increased phosphorylation of NF-H in cell bodies. This suggests that glutamate causes increased NF-H phosphorylation at least in part by activation of stress activated protein kinases.
Brownlees
J
J
Department of Neuroscience, The Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK.
Yates
A
A
Bajaj
N P
NP
Davis
D
D
Anderton
B H
BH
Leigh
P N
PN
Shaw
C E
CE
Miller
C C
CC
D000818:Animals; D019556:COS Cells / Q000187:drug effects; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004789:Enzyme Activation / Q000187:drug effects; D018698:Glutamic Acid / Q000494:pharmacology; D048057:Mitogen-Activated Protein Kinase 10; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016900:Neurofilament Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D011993:Recombinant Fusion Proteins; C051774:neurofilament protein H; D018698:Glutamic Acid; D048057:Mitogen-Activated Protein Kinase 10; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases