Neurofilaments are part of the high molecular weight complex containing neuronal cdc2-like kinase (nclk).
A cdc2-like kinase (nclk, comprised of cdk5 and its activator p25nck5a) that localizes primarily to neuronal cells has recently been identified. Although its precise physiological role remains unclear, a variety of nuclear and cytoplasmic proteins that may be targets for phosphorylation by this kinase have been suggested in various developmental and pathological states. Here we provide evidence for a functional association between nclk and neurofilament proteins: (i) brain neurofilament preparations include cdk5 and p25nck5a; (ii) nclk copurifies with neurofilament proteins using Mono-S and gel-filtration column chromatographic procedures; (iii) neurofilaments are coprecipitated with cdk5 kinase; and (iv) the addition of radiolabeled ATP to the immunoprecipitated complex results in phosphorylation of the cytoskeletal protein. These results are consistent with the formation of a functional macromolecular complex between nclk and neurofilaments in vivo and suggest a possible role for this kinase in regulating neuronal cytoskeletal networks.
Lee
K Y
KY
Department of Anatomy, The University of Calgary, Alberta, Canada. kylee@acs.ucalgary.ca
Johnston
R N
RN
D000818:Animals; D001921:Brain / Q000166:cytology / Q000201:enzymology; D002417:Cattle; D002850:Chromatography, Gel; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D009454:Neurofibrils / Q000201:enzymology* / Q000648:ultrastructure; D016900:Neurofilament Proteins / Q000032:analysis*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis*
D016900:Neurofilament Proteins; D051360:Cyclin-Dependent Kinase 5; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases