Localization of the ubiquitin ligase Dma1 to the fission yeast contractile ring is modulated by phosphorylation

Abstract

The timing of cytokinesis relative to other mitotic events in the fission yeast Schizosaccharomyces pombe is controlled by the septation initiation network (SIN). During a mitotic checkpoint, the SIN is inhibited by the E3 ubiquitin ligase Dma1 to prevent chromosome mis‐segregation. Dma1 dynamically localizes to spindle pole bodies (SPBs) and the contractile ring (CR) during mitosis, though its role at the CR is unknown. Here, we examined whether Dma1 phosphorylation affects its localization or function. We found that preventing Dma1 phosphorylation by substituting the six phosphosites with alanines diminished its CR localization but did not affect its mitotic checkpoint function. These studies reinforce the conclusion that Dma1 localization to the SPB is key to its role in the mitotic checkpoint.

Phosphorylation of Schizosaccharomyces pombe Dss1 mediates direct binding to the ubiquitin‐ligase Dma1 in vitro

“…Fission yeast Dma1, budding yeast Dma1 and Dma2, as well as mammalian RNF8 are members of the unique FHA‐RING domain protein family of E3 ligases and are all linked to mitotic regulation and septin organization (Chahwan et al, 2013 ; Chen et al, 2021 ; Cullati & Gould, 2019 ; Fraschini et al, 2004 ). In S. pombe , Dma1 functions to prevent mitotic exit and cytokinesis during spindle checkpoint arrest by inhibiting septation initiation network signaling (Krapp & Simanis, 2014 ).…”