Revolving movement of a dynamic cluster of actin filaments during mitosis.
The actin cytoskeleton undergoes rapid changes in its architecture during mitosis. Here, we demonstrate novel actin assembly dynamics in M phase. An amorphous cluster of actin filaments appears during prometaphase, revolves horizontally along the cell cortex at a constant angular speed, and fuses into the contractile ring after three to four revolutions. Cdk1 activity is required for the formation of this mitotic actin cluster and its revolving movement. Rapid turnover of actin in the filaments takes place everywhere in the cluster and is also required for its cluster rotation during mitosis. Knockdown of Arp3, a component of the actin filament-nucleating Arp2/3 complex, inhibits the formation of the mitotic actin cluster without affecting other actin structures. These results identify Arp2/3 complex as a key factor in the generation of the dynamic actin cluster during mitosis.
Mitsushima
Masaru
M
Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan.
Aoki
Kazuhiro
K
Ebisuya
Miki
M
Matsumura
Shigeru
S
Yamamoto
Takuya
T
Matsuda
Michiyuki
M
Toyoshima
Fumiko
F
Nishida
Eisuke
E
D008841:Actin Cytoskeleton / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis
D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D016203:CDC2 Protein Kinase