RESUMO
Using human glycogen synthase kinase 3beta (GSK-3beta) as bait in the yeast two-hybrid system, we identified a novel human centrosome associated protein, hNinein. When the full length cDNA of hNinein was sequenced, it showed that an open reading frame encoded a protein consisting of 2047 amino acids with a predicted molecular mass of 239 kDa. The features of this protein include a potential GTP binding site, a large coiled-coil domain together with four leucine zipper domains and a GSK-3beta binding site. Fluorescence microscopy experiment showed that hNinein is localized in the pericentriolar matrix of the centrosome. In addition, hNinein also showed to react with centrosomal autoantibody sera. Our findings suggest that hNinein may be involved in the formation of centrosome matrix and interacts with the GSK-3beta, implying that it may also be regulated by GSK-3beta phosphorylation signaling.
Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas de Ligação ao GTP/genética , Sequência de Aminoácidos , Sequência de Bases , Centrossomo/metabolismo , Clonagem Molecular , Proteínas do Citoesqueleto , DNA Complementar/análise , Proteínas de Ligação ao GTP/metabolismo , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Humanos , Dados de Sequência Molecular , Proteínas Nucleares , Homologia de Sequência de AminoácidosRESUMO
Members of the dynamin superfamily are implicated in vesicle trafficking. Using human glycogen synthase kinase 3 beta (Gsk-3 beta) as bait in the yeast two-hybrid system, we identified a novel human dynamin-like protein IV (HdynIV). When the full-length cDNA of HdynIV was sequenced, it showed that HdynIV's carboxyl terminal lacks a proline-rich domain that can bind to Gsk-3 beta. By Northern blot analysis and isoform-specific PCR, we found that HdynIV is expressed ubiquitously in all human tissues examined. Two transcripts of 2.4 and 4.4 kb are shown to be more abundant in heart, brain, and skeletal muscle. Interestingly, the 2.4-kb transcript is expressed more distinctly in the fetal liver than in the adult liver, suggesting that this protein might play a role during development. In the present report, we have demonstrated that HdynIV interacts with the Gsk-3 beta through its carboxyl-terminal region, implying than HdynIV may also be involved in cell signaling.