Abstract
Adrenocortical microsomes possess a single population of Ins(1,4,5)P3-specific binding sites [IC50 5.9 +/- 0.9 nM; Palmer, Hughes, Lee & Wakelam (1988) Cell. Signalling 1, 147-156]. Competition studies showed that Ins(1:2-cyclic,4,5)P3 exhibits a 21-fold lower affinity for the site than Ins(1,4,5)P3 (IC50 124 +/- 16 nM). The affinity of the binding sites for Ins(1,4,5)P3 was not influenced by the non-hydrolysable GTP analogues GTP gamma S and Gpp[NH]p or by preincubation of the binding protein with a preparation of partially purified protein kinase C in the presence of ATP and TPA (12-O-tetradecanoylphorbol 13-acetate). These observations are discussed with reference to the identify and function of the Ins(1,4,5)P3 binding site.
| Original language | English |
|---|---|
| Pages (from-to) | 593-596 |
| Number of pages | 4 |
| Journal | Biochemical Journal |
| Volume | 260 |
| Issue number | 2 |
| Publication status | Published - 1 Jun 1989 |
| Externally published | Yes |
Keywords
- adrenal cortex
- animals
- binding, competitive
- calcium channels
- cattle
- GTP-binding proteins
- inositol 1,4,5-trisphosphate
- inositol 1,4,5-trisphosphate receptors
- inositol phosphates
- microsomes
- protein kinase C
- receptors, cell surface
- receptors, cytoplasmic and nuclear
- sugar phosphates