Characterization of a MAPKK-like protein kinase TOPK.
A MAPKK-like protein kinase TOPK expresses in a wide range of proliferating cells and tissues such as cancer cells and testis. However, details of this kinase are still uncovered. We investigated the intracellular distribution of TOPK and its association with cdk1/cyclin B and microtubules. In interphase cells, TOPK expresses in cytosol and nucleus without any significant association with microtubule networks. During mitosis, TOPK-Thr-9 was phosphorylated by cdk1/cyclin B and TOPK significantly associates with mitotic spindles. When TOPK expression was suppressed, formation of spindle midzone was thinned and dimmed and cytokinesis was disturbed. We propose that TOPK plays a role in the formation of spindle midzone and in cytokinesis.
Matsumoto
Suguru
S
Department of Molecular Pathology, National University Corporation, Ehime University School of Medicine, Toh-on, Ehime 791-0295, Japan.
Abe
Yasuhito
Y
Fujibuchi
Taketsugu
T
Takeuchi
Takashi
T
Kito
Katsumi
K
Ueda
Norifumi
N
Shigemoto
Kazuhiro
K
Gyo
Kiyofumi
K
D000818:Animals; D019556:COS Cells; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases; D012516:Osteosarcoma / Q000201:enzymology* / Q000473:pathology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
D019926:Cyclin B; D017346:Protein Serine-Threonine Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; C409022:PDZ-binding kinase