270K microtubule-associated protein cross-reacting with anti-MAP2 IgG in the crayfish peripheral nerve axon.
MAPs (microtubule-associated proteins) were isolated from crayfish walking leg nerves. A major MAP was identified as a high molecular weight protein (270K). This protein co-migrated with mammalian MAP2, stimulated the polymerization of rat brain tubulin into microtubules, and was heat resistant. Rotary shadowing revealed that the 270K MAP is a long thin flexible structure. It formed cross-bridges of fine strands, linking microtubules with each other in vitro. These strands resemble the cross-bridges between microtubules observed in the crayfish axon permeabilized with saponin and quick-frozen, deep-etched. Antibodies against mammalian MAP2 cross-reacted with this crayfish MAP and stained the axoplasm of the walking leg nerves. Thus MAPs, especially the 270K MAP, appear to be a major component of the cross-linking strands between microtubules observed in the crayfish axon.
D000818:Animals; D003400:Astacoidea; D001369:Axons / Q000648:ultrastructure*; D003429:Cross Reactions; D003599:Cytoskeleton / Q000648:ultrastructure; D005613:Freeze Etching; D008869:Microtubule-Associated Proteins / Q000276:immunology* / Q000378:metabolism; D008870:Microtubules / Q000648:ultrastructure*; D008970:Molecular Weight
D008869:Microtubule-Associated Proteins