The influence of GTP on the formation and stability of [3H]vincristine (VCR)-tubulin complexes in cytosols from two human rhabdomyosarcoma xenografts which have different sensitivities to VCR has been evaluated. After removal of endogenous GTP the initial rate of [3H]VCR binding and the maximal level of bound drug were 2- to 3-fold higher in the presence of 0.1 mM GTP than in its absence. Similarly, the stability of complexes was GTP-dependent. Complex formed from Rh18 tumors, only moderately sensitive to VCR, dissociated at 37° in the absence of GTP with a half-time of 67 min; complex from Rh12 tumors (exquisitely sensitive to VCR) was more stable. Neither complex dissociated in the presence of 0.1 mM GTP over 2 hr examined.
|Original language||English (US)|
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Mar 28 1986|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology