Colchicine-binding properties of the hepatic tubulin/microtubule system
| Autor: | Michael F. Sorrell, Dean J. Tuma, Richard B. Jennett |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
Male
Biophysics macromolecular substances Tartrate Tritium Microtubules Biochemistry chemistry.chemical_compound Tubulin Microtubule Colchicine binding Animals Colchicine Molecular Biology biology Temperature Sodium tartrate Molecular biology Rats Kinetics Liver chemistry Cytoplasm biology.protein Ultracentrifuge Protein Binding |
| Zdroj: | Archives of Biochemistry and Biophysics. 204:181-190 |
| ISSN: | 0003-9861 |
| DOI: | 10.1016/0003-9861(80)90022-3 |
| Popis: | Colchicine-binding properties of the total cytoplasmic pool of tubulin from rat liver were evaluated in tubulin-stabilizing (TS) supernates. Microtubules were separated from free tubulin using a microtubule-stabilizing solution (MTS) and ultracentrifugation. [3H]Colchicine-binding properties of microtubule-derived tubulin were investigated in supernates prepared after resuspension of MTS pellets in TS. In TS buffer at 37 °C the colchicine-binding activity of the total cytoplasmic pool of tubulin decayed with T 1 2 of 3.39 h. Resuspended pellet tubulin decayed much more rapidly under the same conditions with a T 1 2 of 0.72 h. This rapid time decay of microtubule-derived tubulin was found to be at least partially attributable to prior microtubule-stabilizing solution exposure. Since tartrate has been reported to increase the rate of colchicine binding to tubulin, sodium tartrate (150 m m ) was added to our colchicine-binding system. This addition increased the detectable [3H]colchicine binding by 10% in the total cytoplasmic preparation and by 85% in the resuspended pellet preparation. Addition of tartrate (150 m m ) also resulted in a 105% increase in the T 1 2 for total cytoplasmic tubulin and a 412% increase for microtubule derived tubulin. Total cytoplasmic supernates of liver bound [3H]colchicine linearly over a wide range of tissue concentrations. However, resuspended microtubule-stabilizing solution pellet supernates in tubulin-stabilizing solution showed some increase in colchicine binding per tissue weight in the more dilute samples. Our data which demonstrate differences in colchicine-binding properties for total cytoplasmic and microtubule-derived pools of tubulin suggest that present assays for hepatic tubulin polymerization which assume identical binding properties should be interpreted with caution. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|