The role of the 2- and 3-hydroxyl groups of 1D-myo-inositol 1,4,5-trisphosphate in the mobilisation of calcium from permeabilised human 1321N1 astrocytoma cells.
The functional significance of the 2- and 3-hydroxyl groups of 1 D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] was probed by using Ins(1,4,5)P3 analogues variously modified at positions 2 and 3 or elsewhere. The intrinsic activities of these compounds were compared to that of Ins(1,4,5)P3, using the calcium-mobilising receptor of the 1321N1 human astrocytoma cell line. The ligand-binding affinities were also determined using membrane preparations from rat cerebellum and bovine adrenal cortex. The results show that HO-2 and HO-3 of Ins(1,4,5)P3 have a relatively insignificant role in receptor binding and calcium release. However, the possibility of a regulatory role for the 3-position of Ins(1,4,5)P3 in these processes is proposed.
Wilcox
R A
RA
Department of Pharmacology and Therapeutics, University of Leicester, United Kingdom.
Nahorski
S R
SR
Sawyer
D A
DA
Liu
C
C
Potter
B V
BV
D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001254:Astrocytoma / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006900:Hydroxylation; D015544:Inositol 1,4,5-Trisphosphate / Q000737:chemistry*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015394:Molecular Structure; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium