title: Mitofusin 1 is degraded at G2/M phase through ubiquitylation by MARCH5.
abstract: BACKGROUND
  Mitochondria exhibit a dynamic morphology in cells and their biogenesis and function are integrated with the nuclear cell cycle. In mitotic cells, the filamentous network structure of mitochondria takes on a fragmented form. To date, however, whether mitochondrial fusion activity is regulated in mitosis has yet to be elucidated.
  
  
  RESULTS
  Here, we report that mitochondria were found to be fragmented in G2 phase prior to mitotic entry. Mitofusin 1 (Mfn1), a mitochondrial fusion protein, interacted with cyclin B1, and their interactions became stronger in G2/M phase. In addition, MARCH5, a mitochondrial E3 ubiquitin ligase, reduced Mfn1 levels and the MARCH5-mediated Mfn1 ubiquitylation were enhanced in G2/M phase.
  
  
  CONCLUSIONS
  Mfn1 is degraded through the MARCH5-mediated ubiquitylation in G2/M phase and the cell cycle-dependent degradation of Mfn1 could be facilitated by interaction with cyclin B1/Cdk1 complexes.
authors.affiliation: Department of Biochemistry, Ajou University School of Medicine, Suwon, South Korea. hscho@ajou.ac.kr.
authors.forename: Yong-Yea
authors.initials: YY
authors.lastname: Park
authors.forename: Hyeseong
authors.initials: H
authors.lastname: Cho