title: Centaurin-alpha 1 associates in vitro and in vivo with nucleolin.
abstract: Centaurin-alpha(1) was originally described as a binding partner for phosphoinositides. In spite of the presence of a putative ADP-ribosylation factor (ARF) GTPase-activating protein (GAP) domain, no ARF-GAP activity has been attributed to centaurin-alpha(1) so far. Thus the function of this protein remains to be determined. In order to better understand its intracellular role, we aimed to identify centaurin-alpha(1) partners. Using affinity chromatography followed by mass spectrometry analysis, we identified several potential centaurin-alpha(1) protein partners. Nucleolin, a nucleolar protein involved in ribosome biosynthesis, was the main centaurin-alpha(1) interacting protein. The interaction between centaurin-alpha(1) and nucleolin was confirmed by Western blot analysis and GST pull down assays. Moreover, we have shown that ectopically expressed centaurin-alpha(1) associates in vivo with endogenous nucleolin in human embryonic kidney 293 cells. In addition, the association between nucleolin and centaurin-alpha(1) was disrupted by RNAse treatment, indicating that RNA integrity was necessary for their binding. This suggested that centaurin-alpha(1) was part of a ribonucleoprotein complex.
authors.affiliation: Division of Biomedical and Clinical Laboratory Sciences, The University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK. thierry.dubois@curie.fr
authors.forename: Thierry
authors.initials: T
authors.lastname: Dubois
authors.forename: Eva
authors.initials: E
authors.lastname: Zemlickova
authors.forename: Steven
authors.initials: S
authors.lastname: Howell
authors.forename: Alastair
authors.initials: A
authors.lastname: Aitken
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002458:Cell Fractionation; D002460:Cell Line; D002846:Chromatography, Affinity; D006801:Humans; D007150:Immunohistochemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012756:Sheep; D000097796:Nucleolin
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D012313:RNA; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D000097796:Nucleolin; C100956:ADAP1 protein, human