The cytoskeleton of the squid giant axon
Adjaye, J.; Eagles, P.A.M. (1995). The cytoskeleton of the squid giant axon, in: Abbott, N.J. et al. (Ed.) Cephalopod neurobiology: neuroscience studies in squid, octopus and cuttlefish. pp. 3-13
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| Auteurs | | Top |
- Adjaye, J.
- Eagles, P.A.M.
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| Abstract |
The squid giant axon has given invaluable information about the axonal cytoskeleton. About 6 per cent of the axoplasmic protein is actin, half polymerized as actin filaments, under the axolemma and in the core axoplasm, where they play a role in organelle mobility. Actin-binding proteins like spectrin are present. Around 20 per cent axoplasmic protein is tubulin, and 75 per cent of this is polymeric, forming microtubules similar to those of flagellae. X-ray diffraction studies give information about microtubular substructure, indicating an 8 nm repeat equivalent to the size of the alpha, β tubulin dimer. Microtubule-associated proteins include the motor proteins kinesin and the cortical protein axolinin. The neurofilament is the most abundant cytoskeletal component in squid axoplasm, accounting for 13 per cent axoplasmic protein, and being 95 per cent polymerized. The polypeptide structure has been analysed, and the filaments shown to belong to the family of intermediate filaments. They are altered by two post-translational events: proteolysis and phosphorylation. Progress on cloning squid neurofilament genes is described. |
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