Human Blinkin/AF15q14 is required for chromosome alignment and the mitotic checkpoint through direct interaction with Bub1 and BubR1.
The spindle checkpoint controls mitotic progression. Checkpoint proteins are temporally recruited to kinetochores, but their docking site is unknown. We show that a human kinetochore oncoprotein, AF15q14/blinkin, a member of the Spc105/Spc7/KNL-1 family, directly links spindle checkpoint proteins BubR1 and Bub1 to kinetochores and is required for spindle checkpoint and chromosome alignment. Blinkin RNAi causes accelerated mitosis due to a checkpoint failure and chromosome misalignment resulting from the lack of kinetochore and microtubule attachment. Blinkin RNAi phenotypes resemble the double RNAi phenotypes of Bub1 and BubR1 in living cells. While the carboxy domain associates with the c20orf172/hMis13 and DC8/hMis14 subunits of the hMis12 complex in the inner kinetochore, association of the amino and middle domain of blinkin with the TPR domains in the amino termini of BubR1 and Bub1 is essential for BubR1 and Bub1 to execute their distinct mitotic functions. Blinkin may be the center of the network for generating kinetochore-based checkpoint signaling.
Kiyomitsu
Tomomi
T
CREST Research Program, Japan Science and Technology Corporation, Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
Obuse
Chikashi
C
CREST Research Program, Japan Science and Technology Corporation, Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
Yanagida
Mitsuhiro
M
CREST Research Program, Japan Science and Technology Corporation, Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan. Electronic address: yanagida@kozo.lif.kyoto-u.ac.jp.
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000502:physiology*; D020090:Chromosome Segregation / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000502:physiology; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000502:physiology*; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
D002352:Carrier Proteins; C472643:Knl1 protein, human; D008869:Microtubule-Associated Proteins; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases