title: Inositol(1,3,4,5)tetrakisphosphate-induced activation of sea urchin eggs requires the presence of inositol trisphosphate.
abstract: We have earlier reported that Inositol (1,3,4,5)tetrakisphosphate microinjection will activate eggs of the sea urchin Lytechinus variegatus provided that it is co-injected with inositol (2,4,5)trisphosphate (Irvine and Moor, Biochem. J. 240, 917-920, 1986). Here we extend these observations to show that inositol (1,3,4,5,6)pentakisphosphate is a partial agonist in this assay and the requirement for the presence of inositol (2,4,5)trisphosphate cannot be bypassed by raised, but sub-threshold, Ca2+ concentrations. A mechanism for the proposed stimulation of Ca2+ entry into the cell requiring both inositol tris- and tetrakisphosphates is presented.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004987:Ethers / Q000494:pharmacology; D005260:Female; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism* / Q000494:pharmacology*; D015759:Ionomycin; D009865:Oocytes / Q000187:drug effects*; D012617:Sea Urchins; D013403:Sugar Phosphates / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D004987:Ethers; D007295:Inositol Phosphates; D013403:Sugar Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D015759:Ionomycin; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium