Open AccessA Target of Phosphatidylinositol 3,4,5‐Trisphosphate with a Zinc Finger Motif Similar to that of the ADP‐Ribosylation‐Factor GTPase‐Activating Protein and Two Pleckstrin Homology Domains
Author(s) -
Tanaka Kenichi,
ImajohOhmi Shinobu,
Sawada Takayuki,
Shirai Ryuichi,
Hashimoto Yuichi,
Iwasaki Shigeo,
Kaibuchi Kouzou,
Kanaho Yasunori,
Shirai Toshiyuki,
Terada Yoh,
Kimura Koutarou,
Nagata Satoshi,
Fukui Yasuhisa
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.00512.x
Subject(s) - pleckstrin homology domain , phosphatidylinositol , biology , zinc finger , biochemistry , adp ribosylation factor , gtpase activating protein , peptide sequence , binding protein , complementary dna , microbiology and biotechnology , g protein , signal transduction , transcription factor , gene , cell , golgi apparatus
We have purified a protein that binds phosphatidylinositol 3,4,5‐trisphosphate [PtdIns(3,4,5) P 3 ] using beads bearing a PtdIns(3,4,5) P 3 analogue. This protein, with a molecular mass of 43 kDa, was termed PtdIns(3,4,5) P 3 ‐binding protein. The partial amino acid sequences were determined and a full‐length cDNA encoding the protein was isolated from bovine brain cDNA library. The clone harbored an open reading frame of 373 amino acids which contained one zinc finger motif similar to that of ADP‐ribosylation‐factor GTPase‐activating protein and two pleckstrin homology domains. The entire sequence was 83% similar to centaurin a, another PtdIns(3,4,5) P 3 ‐binding protein. The protein bound PtdIns(3,4,5) P 3 with a higher affinity than it did inositol 1,3,4,5‐tetrakisphosphate, phosphatidylinositol 4,5‐bisphosphate, phosphatidylinositol 3,4‐bisphosphate, and phosphatidylinositol 3‐phosphate suggesting that the binding to PtdIns(3,4,5) P 3 was specific. The binding activity was weaker in the mutants with a point mutation in the conserved sequences in each pleckstrin homology domain. Introduction of both mutations abolished the activity. These results suggest that this new binding protein binds PtdIns(3,4,5) P 3 through two pleckstrin domains present in the molecule.