Related Experiment Video
Updated: Dec 24, 2025
07:49
Spontaneous Formation and Rearrangement of Artificial Lipid Nanotube Networks as a Bottom-Up Model for Endoplasmic Reticulum
Published on: January 22, 2019
8.2K
Regulated lipid synthesis and LEM2/CHMP7 jointly control nuclear envelope closure
Lauren Penfield1, Raakhee Shankar2, Erik Szentgyörgyi3
1Department of Molecular, Cellular and Developmental Biology, New Haven, CT.
The Journal of Cell Biology
|April 10, 2020
Summary
Nuclear envelope (NE) closure in C. elegans oocytes requires regulating endoplasmic reticulum (ER) membrane invasion and ESCRT-mediated remodeling. This study reveals how glycerolipid synthesis prevents NE permeability defects during meiotic spindle formation.
Area of Science:
- Cell Biology
- Molecular Biology
- Developmental Biology
Background:
- The nuclear envelope (NE) maintains cellular integrity by sealing NE holes.
- Nuclear permeability barriers are crucial for proper cell function, especially during cell division.
Purpose of the Study:
- To investigate the mechanisms of NE hole closure surrounding the meiotic spindle in C. elegans oocytes.
- To identify key proteins and pathways involved in regulating NE permeability during oogenesis.
Main Methods:
- 3D imaging analysis to visualize NE structures and membrane dynamics.
- Genetic manipulation of ESCRT-III components and the NE protein phosphatase CNEP-1.
- Assessing nuclear permeability defects and rescuing them by restoring glycerolipid synthesis.
Main Results:
- ESCRT-III components are present but not solely sufficient for NE closure.
- CNEP-1 regulates glycerolipid synthesis, preventing excess ER membrane invasion into NE holes.
- Loss of NE adaptors for ESCRT-III worsens NE permeability defects in cnep-1 mutants.
- Restoring glycerolipid synthesis rescues NE permeability defects in double mutants.
Conclusions:
- Nuclear closure requires coordinated regulation of ER membrane supply and ESCRT-mediated remodeling.
- Glycerolipid synthesis plays a critical role in preventing ER membrane invasion and maintaining NE barrier integrity.
- Both CNEP-1-dependent lipid synthesis and ESCRT-mediated membrane remodeling are essential for proper NE closure.
Related Concept Videos
01:45Regulation of Nuclear Protein Sorting
3.1K
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
3.1K
01:28Assembly of the Lipid Bilayer in the ER
3.9K
Biological membranes are more than just a barrier separating cell cytoplasm from the outside environment. They are highly dynamic and help maintain the integrity and physiological stability of the cells as well as membrane-bound organelles. Membranes also play vital roles in cell-to-cell and intracellular communication.
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
3.9K
01:27Synthesis of Phosphatidylcholine in the ER Membrane
3.9K
The ER synthesizes lipids for building cell membranes and performing cellular functions such as energy storage and signaling. The lipid synthesis machinery embedded in the ER membrane primarily collects all reactants from the cytosol. Following synthesis, the secretory pathway and the ER contact sites distribute these lipids to other cellular organelles. Additionally, the energy-rich triacylglycerides are transported from the ER via lipid droplets.
The major components of all eukaryotic cell...
The major components of all eukaryotic cell...
3.9K
01:26Membrane Fluidity
14.2K
Membrane fluidity is explained by the fluid mosaic model of the cell membrane, which describes the plasma membrane structure as a mosaic of components—including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character.
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is...
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is...
14.2K
01:42Nuclear Export
4.7K
The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
4.7K
01:29Insertion of Multi-pass Transmembrane Proteins in the RER
17.2K
The rough ER membrane synthesizes, assembles, and embeds transmembrane proteins in diverse topologies. These proteins function as transporters or channels and can remain in the ER membrane or are sent to the Golgi complex, lysosome, and cell membrane.
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
17.2K