High‐affinity inositol 1,3,4,5‐tetrakisphosphate receptor from cerebellum: solubilization, partial purification and characterization

FEBS Letters

Hülser, Eckehard¹  Donié, Frédéric¹  Reiser, Georg¹ 

[1] Physiologisch-Chemisches Institut der Universität Tübingen, Hoppe-Seyler-Str. 4, 7400 Tübingen, FRG

关键词: Inositol 1;    3;    4;    5-tetrakisphosphate;    Inositol 1;    4;    5-trisphosphate;    Inositolphosphate receptor;    Heparin;    Ins-P4 (Ins 1;    3;    4;    5-P4);    D-myo-inositol 1;    3;    4;    5-P4;    Ins-P3 (Ins 1;    4;    5-P3);    D-myo-inositol 1;    4;    5-P3;   

DOI  :  10.1016/0014-5793(90)81006-A

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Proteins which bind with high affinity Ins 1,3,4,5-P₄ or Ins 1,4,5-P₃ were solubilized from porcine cerebellar membranes. Both binding activities were separated by heparin-agarose chromatography. The Ins 1,3,4,5-P₄ 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-P₄13 binding protein had an affinity (K _d) for Ins 1,3,4,5-P₄ of 4.6 nM. Ins 1,3,4,5,6-P₅ displaced [³H]Ins 1,3,4,5-P₄binding with a comparable affinity. The Ins 1,3,4,5-P₄binding protein displayed high selectivity for Ins 1,3,4,5-P₄ over other inositolphosphates (IC₅₀ for Ins 1,4,5,6-P₄ 150 nM, for Ins-P₆ 1 μM and for Ins 1,3,4-P₃ 5 μM). Most importantly. Ins 1,4,5-P₃ did not displace [³H]Ins 1,3,4,5-P₄binding at concentrations up to 10μM. Binding of Ins 1,3,4,5-P₄ was maximal in the pH range between 4.5 and 6, was stable with Ca²⁺ concentration varied from 1 nM to 1 mM, and was suppressed by heparin (IC₅₀ about 2 nM). The high affinity receptor for Ins 1,3,4,5-P₄ reported here, which is distinct from the Ins 1,4,5-P₃ receptor might allow to evaluate the possible functional role of Ins 1,3,4,5-P₄ in the cellular signal transduction.

【 授权许可】

Unknown