Demonstration of inositol 1,3,4,5-tetrakisphosphate receptor binding.
Inositol 1,3,4,5-tetrakisphosphate (InsP4) is produced rapidly upon stimulation of the phosphoinositide system and may serve as a second messenger in hormone and neurotransmitter action. In this report we demonstrate specific binding sites for [3H]InsP4 in rat tissue membranes. In cerebellar membranes, [3H]InsP4 binding sites are displaced both by InsP4 and inositol 1,4,5-trisphosphate (InsP3) with similar potency (IC50 approximately equal to 300 nM) whereas several other inositol phosphates are much weaker. We have distinguished the InsP4 binding site from the InsP3 receptor binding site by differences in brain regional and tissue distribution, affinity for InsP4 and InsP3, and sensitivity to calcium.
Theibert
A B
AB
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Supattapone
S
S
Worley
P F
PF
Baraban
J M
JM
Meek
J L
JL
Snyder
S H
SH
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism*; D013873:Thionucleotides / Q000378:metabolism; D014018:Tissue Distribution
D007295:Inositol Phosphates; D011956:Receptors, Cell Surface; D013403:Sugar Phosphates; D013873:Thionucleotides; C081655:inositol-1,3,4,5-tetrakisphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D015544:Inositol 1,4,5-Trisphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D002118:Calcium