EXAMINATION OF THE NATURAL PROTEIN SUBSTRATES AFFECTED BY STAUROSPORINE IN THE DEVELOPING CEREBRAL-CORTEX

The protein substrates affected by staurosporine (SP), the most potent inhibitor of protein kinases yet described, are unknown. In order to approach this problem we incubated cerebral cortex tissue with 0, 20, 50 and 100 nM of SP using [P-32]orthophosphate as radioactive precurso r. The analysis of the phosphoproteins were made with a modified high resolution two dimensional gel electrophoresis, followed by autoradiog raphy. We detected several proteins affected by SP. Specially noticeab le was an approximately 55 kDa protein which strikingly diminished the intensity of phosphorylation. However, the reverse phenomenon was als o observed. To the best of our knowledge this is the first examination of protein substrates affected by SP in intact tissue.