Binding of inositol phosphates to arrestin

FEBS Letters

Palczewski, Krzysztof¹  Pulvermüller, Alexander²  Buczylko, Janina¹  Gutmann, Caroline¹  Hofmann, Klaus Peter² 

[1] R.S. Dow Neurological Sciences Institute of Good Samaritan Hospital and Medical Center, Portland, OR 97209, USA;Institut für Biophysik and Strahlenbiologie der Universität, Albertstr. 23, D-7800 Freiburg, Germany

关键词: Signal transduction;    G-protein;    Rhodopsin;    Arrestin;    Inositol phosphate;    InP3;    D-myo-inositol 1;    4;    5-triphosphate;    InP4;    D-myoinositol 1;    3;    4;    5-tetrakisphosphate;    InP5;    D-myo-inositol 1;    3;    4;    5;    6-pentakisphosphate;    InP6;    inositol hexakisphosphate;    SDS-PAGE;    sodium dodecyl sulfate polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(91)81416-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Arrestin binds to phosphorylated rhodopsin in its light-activated form (metarhodopsin II), blocking thereby its interaction with the G-protein, transducin. In this study, we show that highly phosphorylated forms of inositol compete against the arrestin-rhodopsin interaction. Competition curves and direct binding assays with free arrestin consistently yield affinities in the micromolar range; for example, inositol 1,3,4,5-tetrakisphosphate (InP₄) and inositol hexakisphosphate (InP₆ bind to arrestin with dissociation constants of 12 μM and 5 μM, respectively. Only a small control amount of inositol phosphates is bound, when arrestin interacts with phosphorylated rhodopsin. This argues for a release of bound inositol phosphates by interaction with rhodopsin. Transducin, rhodopsin kinase, or cyclic GMP phosphodiesterase are not affected by inositol phosphates. These observations open a new way to purify arrestin and to inhibit its interaction with rhodopsin. Their physiological significance deserves further investigation.

【 授权许可】

Unknown