title: Bis(1,8-anilinonaphthalenesulfonate). A novel and potent inhibitor of microtubule assembly.
abstract: Two related compounds, 1,8-anilinonaphthalenesulfonate (1,8-ANS) and bis(1,8-anilinonaphthalenesulfonate) (Bis-ANS), are useful fluorescent probes for hydrophobic areas on protein molecules. Using fluorescence, we examined the binding of these compounds to bovine brain tubulin and found that Bis-ANS and 1,8-ANS bound to tubulin with Ki values of 2 and 25 microM, respectively. Bis-ANS potently inhibited the polymerization of tubulin into microtubules in vitro. In the presence of microtubule-associated protein 2, half-maximal inhibition of assembly was obtained at 3 microM Bis-ANS. In the presence of tau protein, half-maximal inhibition was obtained at 15 microM Bis-ANS. Surprisingly, 1,8-ANS, even at 200 microM, did not inhibit assembly. Scatchard analysis indicated one binding site for Bis-ANS on tubulin. Previous reports of 1,8-ANS binding to tubulin may have been influenced by the presence of Bis-ANS which until recently was a common contaminant of commercial supplies. Because of its intense fluorescence in addition to its potent inhibitory effects, Bis-ANS appears to be a useful probe to study microtubule assembly and other interactions involving tubulin.
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D005456:Fluorescent Dyes / Q000494:pharmacology*; D007700:Kinetics; D046911:Macromolecular Substances; D008870:Microtubules / Q000187:drug effects / Q000648:ultrastructure*; D013050:Spectrometry, Fluorescence; D014404:Tubulin / Q000378:metabolism*
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D046911:Macromolecular Substances; D014404:Tubulin; C027132:1-anilino-8-naphthalenesulfonate; C035763:5,5'-bis(8-(phenylamino)-1-naphthalenesulfonate)