Abstract
We report here the molecular cloning, expression, and characterisation of a human homologue of rat centaurin-alpha, which we have termed centaurin-alpha(1). The cDNA contains a single open reading frame, which encodes a 373-amino-acid protein with a calculated molecular weight of 43,429 Daltons. Centaurin-alpha(1) shows high identity at the amino acid level with the other centaurin-alpha homologues, p42(IP4) and PIP(3)BP. Northern analysis revealed that centaurin-alpha(1) expresses as a single 2.5-kb transcript, mainly in the brain. Recombinant centaurin-alpha(1) binds the inositol head group of PtdIns(3,4,5)P(3) and Ins(1,3,4, 5)P(4), with high affinity (K(d) 139.7 +/- 10.5 nM) and inositol phosphate specificity, consistent with it functioning as a putative PtdIns(3,4,5)P(3) receptor. In keeping with this conclusion, we have shown that GFP-tagged centaurin-alpha(1) recruits to the plasma membrane in a PI 3-kinase-dependent manner and the recruitment is inhibited by the PI 3-kinase inhibitor wortmannin. These results suggest that centaurin-alpha(1) can function as an in vivo PtdIns(3, 4,5)P(3) receptor.
Copyright 1999 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Amino Acid Sequence
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Androstadienes / pharmacology
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Animals
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Base Sequence
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Binding Sites
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Brain / metabolism
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CHO Cells
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism
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Cell Membrane / drug effects
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Cell Membrane / metabolism
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Cloning, Molecular
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Cricetinae
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GTPase-Activating Proteins
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Humans
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Inositol Phosphates / metabolism
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Molecular Sequence Data
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Nerve Tissue Proteins / chemistry
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Nerve Tissue Proteins / genetics*
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Nerve Tissue Proteins / metabolism
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Organ Specificity
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphatidylinositol Phosphates / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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RNA, Messenger / analysis
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RNA, Messenger / genetics
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Recombinant Fusion Proteins / metabolism
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Sequence Homology, Amino Acid
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Wortmannin
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Zinc Fingers
Substances
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ADAP1 protein, human
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Adap1 protein, rat
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Adaptor Proteins, Signal Transducing
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Androstadienes
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Carrier Proteins
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GTPase-Activating Proteins
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Inositol Phosphates
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Nerve Tissue Proteins
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Phosphatidylinositol Phosphates
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Phosphoinositide-3 Kinase Inhibitors
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RNA, Messenger
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Recombinant Fusion Proteins
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phosphatidylinositol 3,4,5-triphosphate
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inositol-1,3,4,5-tetrakisphosphate
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Wortmannin