Molecular cloning and functional characterization of a human homologue of centaurin-alpha.
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.
Venkateswarlu
K
K
School of Medical Sciences, University of Bristol, Bristol, BS8 1TD, United Kingdom.
Cullen
P J
PJ
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D020690:GTPase-Activating Proteins; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D000077191:Wortmannin; D016335:Zinc Fingers
D048868:Adaptor Proteins, Signal Transducing; D000730:Androstadienes; D002352:Carrier Proteins; D020690:GTPase-Activating Proteins; D007295:Inositol Phosphates; D009419:Nerve Tissue Proteins; D019869:Phosphatidylinositol 3-Kinases; D018129:Phosphatidylinositol Phosphates; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D000077191:Wortmannin; C100956:ADAP1 protein, human; C491062:Adap1 protein, rat; C060974:phosphatidylinositol 3,4,5-triphosphate; C081655:inositol-1,3,4,5-tetrakisphosphate