When Overexpressed, a Novel Centrosomal Protein, RanBPM, Causes Ectopic Microtubule Nucleation Similar to γ-Tubulin

摘要: A novel human protein with a molecular mass of 55 kD, designated RanBPM, was isolated the two-hybrid method using Ran as bait. Mouse and hamster RanBPM possessed polypeptide identical to one. Furthermore, Saccharomyces cerevisiae found have gene, YGL227w, COOH-terminal half which is 30% RanBPM. Anti-RanBPM antibodies revealed that localized within centrosome throughout cell cycle. Overexpression produced multiple spots were colocalized γ-tubulin acted ectopic microtubule nucleation sites, resulting in reorganization network. cosedimented centrosomal fractions by sucrose- density gradient centrifugation. The formation asters inhibited not only anti- antibodies, but also nonhydrolyzable GTP-Ran. Indeed, specifically interacted GTP-Ran assay. central part stained anti-RanBPM or mAb faded addition GTPγS-Ran, bodies. These results provide evidence Ran-binding protein, involved nucleation, thereby suggesting regulates through