A B-Myb complex containing clathrin and filamin is required for mitotic spindle function.
B-Myb is one member of the vertebrate Myb family of transcription factors and is ubiquitously expressed. B-Myb activates transcription of a group of genes required for the G2/M cell cycle transition by forming the dREAM/Myb-MuvB-like complex, which was originally identified in Drosophila. Mutants of zebrafish B-myb and Drosophila myb exhibit defects in cell cycle progression and genome instability. Although the genome instability caused by a loss of B-Myb has been speculated to be due to abnormal cell cycle progression, the precise mechanism remains unknown. Here, we have purified a B-Myb complex containing clathrin and filamin (Myb-Clafi complex). This complex is required for normal localization of clathrin at the mitotic spindle, which was previously reported to stabilize kinetochore fibres. The Myb-Clafi complex is not tightly associated with the mitotic spindles, suggesting that this complex ferries clathrin to the mitotic spindles. Thus, identification of the Myb-Clafi complex reveals a previously unrecognized function of B-Myb that may contribute to its role in chromosome stability, possibly, tumour suppression.
Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, Tsukuba, Japan.
Tomohiro
T
Yamauchi
Takefumi
T
Ishidao
Teruaki
T
Nomura
Toshie
T
Shinagawa
Yasunori
Y
Tanaka
Shigenobu
S
Yonemura
Shunsuke
S
Ishii
D000818:Animals; D002966:Clathrin / Q000302:isolation & purification / Q000378:metabolism*; D003285:Contractile Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D064448:Filamins; D042822:Genomic Instability; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008938:Mitosis; D046912:Multiprotein Complexes / Q000302:isolation & purification / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb / Q000302:isolation & purification / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
D002966:Clathrin; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D046912:Multiprotein Complexes; D020598:Proto-Oncogene Proteins c-myb