A novel protein with RNA-binding motifs interacts with ataxin-2.
Spinocerebellar ataxia type 2 (SCA2) is caused by expansion of a polyglutamine tract in ataxin-2, a protein of unknown function. Using the yeast two-hybrid system, we identified a novel protein, A2BP1 (ataxin-2 binding protein 1) which binds to the C-terminus of ataxin-2. Northern blot analysis showed that A2BP1 was predominantly expressed in muscle and brain. By immunocfluorescent staining, A2BP1 and ataxin-2 were both localized to the trans -Golgi network. Immunocytochemistry showed that A2BP1 was expressed in the cytoplasm of Purkinje cells and dentate neurons in a pattern similar to that seen for ataxin-2 labeling. Western blot analysis of subcellular fractions indicated enrichment of A2BP1 in the same fractions as ataxin-2. Sequence analysis of the A2BP1 cDNA revealed an RNP motif that is highly conserved among RNA-binding proteins. A2BP1 had striking homology with a human cDNA clone, P83A20, of unknown function and at least two copies of A2BP1 homologs are found in the Caenorhabditis elegans genome database. A2BP1 and related proteins appear to form a novel gene family sharing RNA-binding motifs.
Shibata
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Division of Neurology and Rose Moss Laboratory for Parkinson and Neurodegenerative Diseases, Burns and Allen Research Institute, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, USA.
Huynh
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DP
Pulst
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D000328:Adult; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000067528:Ataxins; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011689:Purkinje Cells / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020754:Spinocerebellar Ataxias / Q000378:metabolism; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques
D000067528:Ataxins; D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; C117552:FOX-1 protein, C elegans; D009419:Nerve Tissue Proteins; D011506:Proteins; D016601:RNA-Binding Proteins