A microsomal membrane preparation from hypocotyls of dark-grown Cucurbita pepo L. (zucchini) seedlings contains specific high-affinity binding sites for the non-hydrolyzable GTP analog guanosine 5′-[γ-thio]triphosphate (GTP-γ-S). Both the binding affinity and the pattern of binding specificity for GTP and guanine nucleoside triphosphate analogs are shared with the more thoroughly characterized animal G-proteins that are known to be involved in signal transduction. The sensitivity of GTP-γ-S binding to Mg+2 ions and temperature was similar to that reported for rabbit liver G-protein, although the plant complex dissociated more readily. GTP-γ-S could be recovered unchanged from the binding complex. Proteins (Mr 33 and 50 kDa) present in zucchini membrane preparations were revealed by immunoblotting with antiserum specific for the a subunit of platelet Gs. These may be homologous to animal G-proteins.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Sep 30 1988|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology