Related Experiment Video
Updated: Jul 28, 2025
06:12
Author Spotlight: THP-1 Macrophage Response to LPS/ATP — Unveiling the Pyroptosis, Apoptosis, and Necroptosis Spectrum
Published on: May 3, 2024
2.1K
The bacterial effector SidN/Lpg1083 promotes cell death by targeting Lamin-B2
Jiajia Gao1, Wenwen Xu1, Feng Tang1
1Institute of Health Sciences and Technology, Institutes of Material Science and Information Technology, Anhui University, Hefei 230601, China.
Journal of Molecular Cell Biology
|May 30, 2023
Summary
Legionella pneumophila uses the type IVB secretion system (T4SS) effector SidN to disrupt the nuclear envelope. This effector protein targets Lamin-B2, causing cell death and aiding pathogen dissemination.
Area of Science:
- Microbiology
- Cell Biology
- Structural Biology
Background:
- Legionella pneumophila utilizes a type IVB secretion system (T4SS) to deliver over 330 effectors, hijacking host cell pathways.
- Many L. pneumophila effectors remain uncharacterized due to low sequence homology and functional redundancy.
Purpose of the Study:
- To investigate the molecular characterization and function of the T4SS effector SidN.
- To elucidate the mechanism by which SidN impacts host cells during L. pneumophila infection.
Main Methods:
- Subcellular localization studies to identify SidN's cellular target.
- Structural analysis to determine SidN's fold and functional domains.
- Co-immunoprecipitation and in vitro binding assays to identify host protein interactions.
- Microscopy to observe effects on nuclear envelope integrity.
Main Results:
- SidN localizes to the nuclear envelope, with its N-terminal domain essential for this localization.
- SidN possesses a novel structural fold.
- SidN is imported into the nucleus via Importin-13 and binds to Lamin-B2.
- SidN binding disrupts nuclear envelope integrity, leading to cell death.
Conclusions:
- SidN is a nuclear envelope-targeting effector of L. pneumophila that disrupts host cell integrity.
- The interaction with Lamin-B2 is critical for SidN-mediated cell death.
- This mechanism may represent a strategy for L. pneumophila to promote host cell lysis and escape for secondary infections.
Related Concept Videos
01:17The Extrinsic Apoptotic Pathway
6.5K
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
6.5K
01:31The Intrinsic Apoptotic Pathway
6.6K
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
6.6K
01:18Autophagic Cell Death
3.5K
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
3.5K
01:30Overview of Cell Death
7.4K
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the...
7.4K
01:23Negative Regulator Molecules
35.5K
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
35.5K
01:17Phagocytosis of Apoptotic Cells
3.9K
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized...
Normal cells contain receptors that prevent them from being recognized...
3.9K