Premium
High‐affinity inositol 1,3,4,5‐tetrakisphosphate receptor from cerebellum: solubilization, partial purification and characterization
Author(s) -
Donié Frédéric,
Hülser Eckehard,
Reiser Georg
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81006-a
Subject(s) - solubilization , chemistry , cerebellum , biochemistry , receptor , inositol , chromatography , affinity chromatography , biophysics , biology , neuroscience , enzyme
Proteins which bind with high affinity Ins 1,3,4,5‐P 4 or Ins 1,4,5‐P 3 were solubilized from porcine cerebellar membranes. Both binding activities were separated by heparin‐agarose chromatography. The Ins 1,3,4,5‐P 4 receptor was partially purified with an approximately 1000‐fold enrichment as compared to the membrane preparation. In the receptor‐enriched preparation the Ins 1,3,4,5‐P 4 13 binding protein had an affinity ( K d ) for Ins 1,3,4,5‐P 4 of 4.6 nM. Ins 1,3,4,5,6‐P 5 displaced [ 3 H]Ins 1,3,4,5‐P 4 binding with a comparable affinity. The Ins 1,3,4,5‐P 4 binding protein displayed high selectivity for Ins 1,3,4,5‐P 4 over other inositolphosphates (IC 50 for Ins 1,4,5,6‐P 4 150 nM, for Ins‐P 6 1 μM and for Ins 1,3,4‐P 3 5 μM). Most importantly. Ins 1,4,5‐P 3 did not displace [ 3 H]Ins 1,3,4,5‐P 4 binding at concentrations up to 10μM. Binding of Ins 1,3,4,5‐P 4 was maximal in the pH range between 4.5 and 6, was stable with Ca 2+ concentration varied from 1 nM to 1 mM, and was suppressed by heparin (IC 50 about 2 nM). The high affinity receptor for Ins 1,3,4,5‐P 4 reported here, which is distinct from the Ins 1,4,5‐P 3 receptor might allow to evaluate the possible functional role of Ins 1,3,4,5‐P 4 in the cellular signal transduction.