The transcription repressor BACH1 performs mutually independent dual roles in transcription regulation and chromosome alignment during mitosis by supporting polar ejection force of mitotic spindle. We now found that the mitotic spindles became oblique relative to the adhesion surface following endogenous BACH1 depletion in HeLa cells. This spindle orientation rearrangement was rescued by re-expression of BACH1 depending on its interactions with HMMR and CRM1, both of which are required for the positioning of mitotic spindle, but independently of its DNA-binding activity. A mass spectrometry analysis of BACH1 complexes in interphase and M phase revealed that BACH1 lost during mitosis interactions with proteins involved in chromatin and gene expression but retained interactions with HMMR and its known partners including CHICA. By analyzing BACH1 modification using stable isotope labeling with amino acids in cell culture, mitosis-specific phosphorylations of BACH1 were observed, and mutations of these residues abolished the activity of BACH1 to restore mitotic spindle orientation in knockdown cells and to interact with HMMR. Detailed histological analysis of Bach1-deficient mice revealed lengthening of the epithelial fold structures of the intestine. These observations suggest that BACH1 performs stabilization of mitotic spindle orientation together with HMMR and CRM1 in mitosis, and that the cell cycle-specific phosphorylation switches the transcriptional and mitotic functions of BACH1.
-
Cover Image
Cover Image
The human immunodeficiency virus. In this issue of the Biochemical Journal, Parajuli et al. report that restricted the HIV Env (envelope glycoprotein) glycan engagement by a lectin reengineered DAVEI protein chimera is sufficient for virolysis. For details, see pages 931–957.
Phosphorylation of BACH1 switches its function from transcription factor to mitotic chromosome regulator and promotes its interaction with HMMR
Jie Li, Hiroki Shima, Hironari Nishizawa, Masatoshi Ikeda, Andrey Brydun, Mitsuyo Matsumoto, Hiroki Kato, Yuriko Saiki, Liang Liu, Miki Watanabe-Matsui, Kenji Iemura, Kozo Tanaka, Takuma Shiraki, Kazuhiko Igarashi; Phosphorylation of BACH1 switches its function from transcription factor to mitotic chromosome regulator and promotes its interaction with HMMR. Biochem J 15 March 2018; 475 (5): 981–1002. doi: https://doi.org/10.1042/BCJ20170520
Download citation file:
Sign in
Sign in to your personal account
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |