title: Proteolysis of tau by calpain.
abstract: The calpain-induced proteolysis of tau associated with twice-cycled microtubules or from a total brain heat-stable fraction was studied. Twice-cycled microtubule tau was rapidly hydrolyzed by calpain. In contrast, tau purified from the total brain heat-stable fraction was very resistant to degradation by calpain. These results clearly demonstrate that there are at least 2 populations of tau in the brain based on calpain-sensitivity, a calpain-sensitive form that is associated with microtubules and a calpain-resistant form that may represent another population of tau in the brain.
authors.affiliation: Department of Neurology, University of Alabama, Birmingham 35294.
authors.forename: G V
authors.initials: GV
authors.lastname: Johnson
authors.forename: R S
authors.initials: RS
authors.lastname: Jope
authors.forename: L I
authors.initials: LI
authors.lastname: Binder
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002417:Cattle; D015151:Immunoblotting; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016875:tau Proteins
chemical_list: D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D016875:tau Proteins; D002154:Calpain