We examined the effect of herbimycin A, a potent inhibitor of tyrosine kinase, on NIH(ret) cells and TPC-1 papillary thyroid carcinoma cells, both of which express the active ret genes. Herbimycin A reversed the morphology of NIH(ret) cells to flat cells with a concomitant reassembly of microfilament bundles. On the other hand, it did not induce a significant change in cell shape of TPC-1 cells. When tyrosine kinase activities of the active ret gene products in herbimycin A-treated NIH(ret) and TPC-1 cells were examined in immunocomplex kinase assays, they drastically decreased in both cells as compared with untreated cells. In addition, herbimycin A strongly inhibited tyrosine phosphorylation of 40 kDa and 31 kDa proteins present in the immunoprecipitates of both cells, suggesting that these proteins could associate with the Ret proteins.
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 31-08-1993|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology