TY - JOUR
T1 - When overexpressed, a novel centrosomal protein, RanBPM, causes ectopic microtubule nucleation similar to γ-tubulin
AU - Nakamura, Masafumi
AU - Masuda, Hirohisa
AU - Horii, Johji
AU - Kuma, Kei Ichi
AU - Yokoyama, Nobuhiko
AU - Ohba, Tomoyuki
AU - Nishitani, Hideo
AU - Miyata, Takashi
AU - Tanaka, Masao
AU - Nishimoto, Takeharu
PY - 1998/11/16
Y1 - 1998/11/16
N2 - A novel human protein with a molecular mass of 55 kD, designated RanBPM, was isolated with the two-hybrid method using Ran as a bait. Mouse and hamster RanBPM possessed a polypeptide identical to the human one. Furthermore, Saccharomyces cerevisiae was found to have a gene, YGL227w, the COOH-terminal half of which is 30% identical to RanBPM. Anti-RanBPM antibodies revealed that RanBPM was localized within the centrosome throughout the cell cycle. Overexpression of RanBPM produced multiple spots which were colocalized with γ-tubulin and acted as ectopic microtubule nucleation sites, resulting in a reorganization of microtubule network. RanBPM cosedimented with the centrosomal fractions by sucrose-density gradient centrifugation. The formation of microtubule asters was inhibited not only by anti-RanBPM antibodies, but also by nonhydrolyzable GTP-Ran. Indeed, RanBPM specifically interacted with GTP-Ran in two-hybrid assay. The central part of asters stained by anti-RanBPM antibodies or by the mAb to γ- tubulin was faded by the addition of GTPγS-Ran, but not by the addition of anti-RanBPM antibodies. These results provide evidence that the Ran-binding protein, RanBPM, is involved in microtubule nucleation, thereby suggesting that Ran regulates the centrosome through RanBPM.
AB - A novel human protein with a molecular mass of 55 kD, designated RanBPM, was isolated with the two-hybrid method using Ran as a bait. Mouse and hamster RanBPM possessed a polypeptide identical to the human one. Furthermore, Saccharomyces cerevisiae was found to have a gene, YGL227w, the COOH-terminal half of which is 30% identical to RanBPM. Anti-RanBPM antibodies revealed that RanBPM was localized within the centrosome throughout the cell cycle. Overexpression of RanBPM produced multiple spots which were colocalized with γ-tubulin and acted as ectopic microtubule nucleation sites, resulting in a reorganization of microtubule network. RanBPM cosedimented with the centrosomal fractions by sucrose-density gradient centrifugation. The formation of microtubule asters was inhibited not only by anti-RanBPM antibodies, but also by nonhydrolyzable GTP-Ran. Indeed, RanBPM specifically interacted with GTP-Ran in two-hybrid assay. The central part of asters stained by anti-RanBPM antibodies or by the mAb to γ- tubulin was faded by the addition of GTPγS-Ran, but not by the addition of anti-RanBPM antibodies. These results provide evidence that the Ran-binding protein, RanBPM, is involved in microtubule nucleation, thereby suggesting that Ran regulates the centrosome through RanBPM.
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U2 - 10.1083/jcb.143.4.1041
DO - 10.1083/jcb.143.4.1041
M3 - Article
C2 - 9817760
AN - SCOPUS:0032538999
VL - 143
SP - 1041
EP - 1052
JO - Journal of Cell Biology
JF - Journal of Cell Biology
SN - 0021-9525
IS - 4
ER -