Disease relevance of NEFL

• We dephosphorylated NF-H using Escherichia coli alkaline phosphatase, then reassembled it into neurofilaments with NF-M and NF-L, and into NF-H filaments with NF-H alone [1].

High impact information on NEFL

• Using coumarin-labeled NF-L as fluorescence donor and fluorescein-labeled NF-L as the fluorescence acceptor, assembly of NF filaments was induced by rapidly raising the NaCl concentration to 170 mM, and the kinetics was followed by the decrease in the donor fluorescence [2].
• The core component, NF-L, was stoichiometrically labeled at cysteine 321 with fluorescein, coumarin, or biotin-maleimide to produce assembly-competent fluorescent or biotinylated derivatives, respectively [2].
• Assembly of NF-L subunits into filaments does not require nucleotide binding or hydrolysis but is strongly dependent on ionic strength, pH, and temperature [2].
• Given the concentration of NF-L found in nerve cells and the possibility of regulating this pool, these results provide the first information that intermediate filaments are dynamic structures and that NF-L within the NF complex is in dynamic equilibrium with a small but kinetically active pool of unassembled NF-L units [2].
• Phosphorylation of native and reassembled neurofilaments composed of NF-L, NF-M, and NF-H by the catalytic subunit of cAMP-dependent protein kinase [3].

Biological context of NEFL

• Ser(66) was previously not known to be phosphorylated in NFL of other species, while two sites (Ser(55) and Ser(472)) are consistent with the phosphorylations observed in other mammalian NFLs [4].
• The amino acid sequence of bovine brain micro glutamic acid-rich protein was determined by analysis of tryptic and Trimeresurus flavoviridis protease peptides of the molecule [5].
• Soluble NF-L is phosphorylated on the head domain peptide L-3, whereas NF-L within intact filaments is phosphorylated only on the tail domain peptide L-1 [6].
• The effect of phosphorylation by cyclic AMP dependent protein kinase on the assembly of the core-forming 68 KDa neurofilament subunit protein (NF-L) was studied in vitro by fluorescence energy transfer and electron microscopy [7].
• Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic [8].

Anatomical context of NEFL

• The radioiodinated neurofilament proteins (untreated and dephosphorylated) were incubated in the presence and absence of calpain from rabbit skeletal muscle, and the degradation rates of large (NF-H), mid-sized (NF-M) and small (NF-L) neurofilament polypeptides were analysed by SDS/polyacrylamide-gel electrophoresis and autoradiography [9].
• We carried out immunolabeling studies of purified bovine spinal cord neurofilaments (NFs) and filaments reconstituted from several combinations of the NF triplet polypeptides, NF-H, NF-M, and NF-L [10].
• CKI from rabbit reticulocytes phosphorylated all three NF subunits (NF-H, NF-M and NF-L) [11].
• Using the smallest subunit (NF-L) of a neurofilament and a glial fibrillary acidic protein, the subunit arrangement in intermediate filaments was studied by low-angle rotary shadowing [12].
• In conclusion, NF-L in bovine chromaffin cells demonstrates that at least one neuronal trait persists in these catecholamine-producing cells of the mature adrenal gland [13].

Associations of NEFL with chemical compounds

• Co-incubation of purified high (NF-H) and middle (NF-M) but not low (NF-L) molecular weight NF subunits prevents this AlCl3-induced alteration in electrophoretic migration [14].
• In addition, much of this component was easily isolated on DE-52 column chromatography of the reassembled crude neurofilament proteins with buffers containing 6 M urea, while the low molecular weight component of the neurofilaments (NF-L, 70 kDa) was hardly detected [15].
• Assembled NF-L filaments could also be phosphorylated by cyclic AMP dependent protein kinase indicating that the sites were accessible [7].

Enzymatic interactions of NEFL

• In the native NF, A-kinase phosphorylated each NF subunit with stoichiometries of 4 mol/mol for NF-L, 6 mol/mol for NF-M, and 4 mol/mol for NF-H [3].

Other interactions of NEFL

• Molecular mass information shows that there is one-half equivalent phosphate group on NFL and 24 on NFM [4].

Analytical, diagnostic and therapeutic context of NEFL

• Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) shows molecular masses for bovine NFP subunits of 63, 105, and 125 kDa for NFL, NFM, and NFH [4].
• Titration of NF-L with NF-M indicated that complex formation was complete at an approximately equimolar ratio of the two proteins [16].
• Individual components of the NF triplet, i.e. NF-L, NF-M and NF-H, were purified by DE-52 and Mono-Q anion exchange chromatographies in the presence of 6 M-urea and were assembled in various combinations into filaments [17].
• When rounded chromaffin cells in culture were examined, double-label immunofluorescence microscopy revealed an IFAP-300kDa/NF-L-positive juxtanuclear aggregate [18].

References