TUBULIN AGGREGATES INDUCED BY NI2+ PRESENT MICROTUBULAR CHARACTERISTICS

Rat brain tubulin in a proper buffered solution became insoluble in th e presence of 10 mM NiCl2, and sedimented at centrifugal forces as low as 500 x g for 30 min. Both nickel-sedimented and microtubular tubuli n conserved 65% of colchicine binding activity after 25 days of storag e at -20 degrees C. However in brain cytosol, only 9% of the initial b inding activity was conserved. The electrophoretic mobility of tubulin recovered from aggregates also remained unaltered. Therefore the aggr egates formed with Ni2+ share important physicochemical properties wit h microtubules.