As eukaryotic cells progress through cell division, the nuclear envelope (NE) membrane must expand to accommodate the formation of progeny nuclei. In Saccharomyces cerevisiae, closed mitosis allows visualization of NE biogenesis during mitosis. During this period, the SUMO E3 ligase Siz2 binds the inner nuclear membrane (INM) and initiates a wave of INM protein SUMOylation. Here, we show these events increase INM levels of phosphatidic acid (PA), an intermediate of phospholipid biogenesis, and are necessary for normal mitotic NE membrane expansion. The increase in INM PA is driven by the Siz2-mediated inhibition of the PA phosphatase Pah1. During mitosis, this results from the binding of Siz2 to the INM and dissociation of Spo7 and Nem1, a complex required for the activation of Pah1. As cells enter interphase, the process is then reversed by the deSUMOylase Ulp1. This work further establishes a central role for temporally controlled INM SUMOylation in coordinating processes, including membrane expansion, that regulate NE biogenesis during mitosis.
SUMOylation at the inner nuclear membrane facilitates nuclear envelope biogenesis during mitosis
Disclosures: The authors declare no competing interests exist.
- Award Id(s): MOP 106502,PJT 180467
- Award Id(s): 2P41GM109824-06,2R01GM112108-05,R01GM124120
Natasha O. Saik, Christopher Ptak, Saif Rehman, John D. Aitchison, Ben Montpetit, Richard W. Wozniak; SUMOylation at the inner nuclear membrane facilitates nuclear envelope biogenesis during mitosis. J Cell Biol 7 August 2023; 222 (8): e202208137. doi: https://doi.org/10.1083/jcb.202208137
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