| Autor: |
Monika Gramzow, G. Uhlenbruck, Yoshiyuki Kuchino, Ursula Friese, W. E. G. Müller, B. Kurelec, H. C. Schröder |
| Rok vydání: |
1988 |
| Předmět: |
|
| Zdroj: |
Journal of Biological Chemistry. 263:16334-16340 |
| ISSN: |
0021-9258 |
| DOI: |
10.1016/s0021-9258(18)37597-5 |
| Popis: |
Northern blot data as well as immunocytochemical and immunoblotting experiments indicate that the sponge Geodia cydonium contains the ras gene (or ras-related gene). The ras gene transcript has a size of 1.5 kilobases and the ras gene product has an Mr of 23,000-26,000. While dissociated G. cydonium cells lack ras gene product, ras gene expression can be induced by incubating the cells with the cell-binding fragment of the homologous aggregation factor. Maximal expression was observed 10-15 h after addition of the fragment. The sponge ras protein was partially purified by immunoprecipitation and bound GTP with a dissociation constant of 1.8 x 10(-6) M. It was found to be associated with the cell membrane. Autoradiographic studies revealed that the ras protein binds to the plasma membrane-associated anti-aggregation receptor and thereby mediates the mitogenic response, caused by the homologous lectin. It is hypothesized that sponges are provided in addition to the aggregation factor-caused and protein kinase C-mediated pathway with a second mechanism of transduction of mitotic signals, the lectin-caused and ras-mediated signaling. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
