Sculpting nuclear envelope identity from the endoplasmic reticulum during the cell cycle

ABSTRACT

The nuclear envelope (NE) regulates nuclear functions, including transcription, nucleocytoplasmic transport, and protein quality control. While the outer membrane of the NE is directly continuous with the endoplasmic reticulum (ER), the NE has an overall distinct protein composition from the ER, which is crucial for its functions. During open mitosis in higher eukaryotes, the NE disassembles during mitotic entry and then reforms as a functional territory at the end of mitosis to reestablish nucleocytoplasmic compartmentalization. In this review, we examine the known mechanisms by which the functional NE reconstitutes from the mitotic ER in the continuous ER–NE endomembrane system during open mitosis. Furthermore, based on recent findings indicating that the NE possesses unique lipid metabolism and quality control mechanisms distinct from those of the ER, we explore the maintenance of NE identity and homeostasis during interphase. We also highlight the potential significance of membrane junctions between the ER and NE.

KEYWORDS:

• Cell cycle
• endoplasmic reticulum
• ER–NE junction
• mitosis
• nuclear assembly
• nuclear envelope
• nuclear pore complex

Acknowledgments

We thank Tamara Völkerer for comments on the manuscript. P.D. is a recipient of VIP2 fellowship from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie (grant agreement no. 847548). H.B.T. received a DOC Fellowship of the Austrian Academy of Sciences (no. 25951) and a Max Perutz PhD Fellowship (University of Vienna and the Medical University of Vienna). S.O. is supported by laboratory startup funding from the Medical University of Vienna, by the Vienna Science and Technology Fund (WWTF; project LS19-001), and the Austrian Science Fund (FWF) grant (P 36743).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

No data was used for the research described in the article.

Additional information

Funding

The work was supported by the HORIZON EUROPE Marie Sklodowska-Curie Actions [847548]; WWTF [LS19-001]; Austrian Research Fund (FWF) [P 36743]; Österreichischen Akademie der Wissenschaften [25951].