cDNA cloning of porcine p42IP4, a membrane‐associated and cytosolic 42 kDa inositol(1,3,4,5)tetrakisphosphate receptor from pig brain with similarly high affinity for phosphatidylinositol (3,4,5)P3

FEBS Letters

Lottspeich, F¹  Stricker, R²  Fischer, J²  Reiser, G²  Walter, U³  Hülser, E²  Jarchau, Th³ 

[1] Max-Planck-Institut für Biochemie, Martinsried, Germany;Institut für Neurobiochemie, Medizinische Fakultät der Otto-von-Guericke-Universität, Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany;Medizinische Univeristätsklinik, Würzburg, Germany

关键词: Signal transduction;    Inositol phosphate;    Phosphatidylinositol 3-kinase;    Ins-P4;    PtdInsP3;    Centaurin-α;    CAPS;    3-[cyclohexylamino]-1-propanesulfonic acid;    GroPIP3;    glycero phosphatidylinositol(3;    4;    5) trisphosphate;    PtdIns(3;    4;    5)P3 (PtdInsP3);    phosphatidylinositol(3;    4;    5)-trisphosphate;    Ins(x1;    x2;    ..;    xn)Pn;    myo-inositol(x1;    x2;    ..;    xn)n-phosphate;   

DOI  :  10.1016/S0014-5793(97)00188-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We previously identified a 42 kDa Ins(1,3,4,5)P₄ (InsP₄) receptor protein (p42^IP4) in brain membranes from several species. Here the cDNA sequence of p42^IP4 was obtained by PCR using degenerate primers derived from peptide sequences of proteolytic fragments of the porcine protein and by subsequent screening of a pig brain cDNA library. The derived peptide sequence of 374 amino acids for porcine p42^IP4 is 45 amino acids shorter at the C-terminus than centaurin-α from rat (84% homology) and has a calculated molecular mass of 43 kDa. From the InsP₄ binding activity present in brain tissue homogenate about 25% is found in the cytosolic fraction and 75% associated with microsomes. Both activities are due to p42^IP4 since (i) a peptide-specific antiserum recognizing specifically p42^IP4 labels the InsP₄ receptor protein in membranes and in the cytosol, (ii) the antiserum immunoprecipitates both the membrane protein and the cytosolic protein of 42 kDa, (iii) the InsP₄ binding activity released by high salt or by alkaline extraction from membranes is identified immunologically as the 42 kDa protein, and (iv) the affinity for InsP₄ and specificity for various inositolphosphates are similar for the membrane-associated and for the soluble p42^IP4. The functional importance of p42^IP4 is highlighted by the identical affinity for InsP₄ and for phosphatidylinositol (3,4,5)P₃ (K_i=1.6 and 0.9 nM, respectively). Thus, the InsP₄ receptor, apparently a peripheral membrane protein, which exists also as a cytosolic protein can transfer the signals mediated by InsP₄ or by PtdInsP₃ between membranes and cytosolic compartment. © 1997 Federation of European Biochemical Societies

【 授权许可】

Unknown