mitotic nuclear membrane reassembly

Definition

Target type: biologicalprocess

The mitotic cell cycle process involving ESCRTIII that results in reformation of the nuclear envelope after mitotic nuclear division. In organisms undergoing closed mitosis this involves resealing or 'repair' of the nuclear envelope in the nuclear bridge. [PMID:26040712, PMID:28242692, PMID:32109380, PMID:32848252]

Mitotic nuclear membrane reassembly is a complex and tightly regulated process that occurs after chromosome segregation during mitosis. It involves the coordinated action of multiple proteins and factors, leading to the formation of a new nuclear envelope around the decondensed chromosomes.

Here's a breakdown of the key steps involved:

1. **Dephosphorylation of Nuclear Envelope Proteins:** During mitosis, the nuclear envelope breaks down into vesicles and disperses throughout the cytoplasm. This breakdown is triggered by the phosphorylation of lamins and other nuclear envelope proteins by kinases like CDK1. After chromosome segregation, phosphatases like PP2A remove these phosphate groups, allowing the proteins to reassemble.

2. **Vesicle Aggregation and Fusion:** The dispersed nuclear envelope vesicles begin to aggregate around the decondensing chromosomes. This aggregation is mediated by interactions between proteins like lamin B receptor (LBR) and RanGTP, which are present on the vesicles. The vesicles then fuse together, forming a continuous membrane sheet.

3. **Nuclear Pore Complex (NPC) Assembly:** The NPCs, which are large protein complexes that regulate the transport of molecules across the nuclear envelope, are reassembled during this process. NPC components like nucleoporins associate with the membrane sheet and form the functional pores.

4. **Chromatin Association:** The newly formed nuclear envelope interacts with the decondensing chromosomes. This interaction is crucial for anchoring the envelope to the nucleus and for ensuring proper nuclear organization.

5. **Lamin Assembly:** The nuclear lamins, which form the structural framework of the nuclear envelope, polymerize into a meshwork beneath the inner nuclear membrane. This meshwork provides support and helps maintain the shape of the nucleus.

6. **Nuclear Envelope Expansion and Maturation:** As the nuclear envelope expands, it encloses the entire genome. The envelope then matures, acquiring its characteristic structure and functions. This maturation involves the recruitment of various proteins and factors, including transcription factors, chromatin remodeling complexes, and enzymes involved in DNA replication and repair.

This process is essential for the proper segregation of chromosomes and the formation of two daughter cells. It also ensures the re-establishment of the nuclear environment necessary for DNA replication and gene expression. Errors in nuclear membrane reassembly can lead to various cellular defects, including developmental abnormalities and cancer.'
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Proteins (2)

Compounds (34)