Triton-soluble phosphovariants of the high molecular weight neurofilament subunit from NB2a/dl cells are assembly-competent: Implications for normal and abnormal neurofilament assembly

摘要: NB2a/dl cells incorporate neurofilaments (NFs) containing extensively phosphorylated high (NF-H) molecular weight subunits into the Tritoninsoluble cytoskeleton of axonal neurites elaborated during differentiation with dibutyryl cAMP. However, immunocytochemical and biochemical analyses demonstrate constitutive expression extensive phosphorylation a sizeable pool (200 kDa) NF-H. We examined by cell-free whether or not this Triton-soluble NF-H was assembly-competent in analyses. fractions from 35S-radiolabeled were incubated dissociated mouse CNS Triton-insoluble cytoskeletons that had been treatment 6 M urea. Following overnight dialysis to remove urea, low-speed centrifugation sediment resulted co-sedimentation radiolabeled NF-H, indicating capable association structures. Triton-soluble, also co-assembling purified NF-L. high-speed (100,000 × g for 1 h) any oligomeric assemblies, fraction mixed NF-L solubilized sedimented both cells, demonstrating variants are assembly-competent. These data suggest represent precursors NF assembly, indicate their assembly within must be under temporal spatial regulation.