Related Experiment Video
Updated: Dec 18, 2025
10:25
Dual-color Correlative Light and Electron Microscopy for the Visualization of Interactions between Mitochondria and Lysosomes
Published on: September 27, 2024
951
MERIT, a cellular system coordinating lysosomal repair, removal and replacement
Jingyue Jia1,2, Aurore Claude-Taupin1,2, Yuexi Gu1,2
1Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center , Albuquerque, NM, USA.
Autophagy
|June 11, 2020
Summary
The MERIT system, involving galectin 3 (LGALS3), repairs and removes damaged lysosomes. This cellular defense protects endomembrane integrity against various damaging agents.
Area of Science:
- Cell Biology
- Molecular Biology
- Cellular Repair Mechanisms
Background:
- Cellular membrane integrity is crucial for survival and function.
- Existing mechanisms for protecting cellular and intracellular membranes are not fully understood.
- Lysosomal membrane damage can compromise cellular health.
Purpose of the Study:
- To investigate the cellular system MERIT (lysosomal membrane repair, removal, and replacement).
- To elucidate the role of galectins, specifically LGALS3, in lysosomal membrane repair and homeostasis.
- To understand how the MERIT system protects the endolysosomal network.
Main Methods:
- Investigated the MERIT system's sequential steps: ESCRT-dependent repair, autophagy-mediated removal, and lysosomal biogenesis.
- Utilized galectins, particularly LGALS3, as key regulators of the MERIT pathway.
- Examined the interplay between LGALS3, ESCRT components (PDCD6IP/ALIX, CHMP4A, CHMPB), and autophagy receptor TRIM16.
- Assessed the impact of LGALS3 deficiency on lysosomal repair, autophagy, and TFEB-mediated biogenesis.
- Tested the MERIT system's protective capacity against lysosomotropic drugs, Mycobacterium tuberculosis, and MAPT/tau.
Main Results:
- LGALS3 detects lysosomal membrane damage and recruits ESCRT machinery for repair.
- LGALS3 collaborates with TRIM16 to promote the removal of damaged lysosomes via autophagy.
- Absence of LGALS3 impairs repair and autophagy, leading to increased TFEB activation for lysosomal biogenesis.
- The MERIT system effectively protects the endolysosomal network from diverse damaging agents.
Conclusions:
- The MERIT system, governed by LGALS3, is a critical cellular defense mechanism for maintaining lysosomal and endomembrane integrity.
- LGALS3 plays a dual role in initiating lysosomal repair and subsequently engaging autophagy for damaged organelle removal.
- The MERIT pathway provides robust protection against various cellular insults, highlighting its importance in cellular homeostasis.
Related Concept Videos
01:31Lysosomes
25.0K
Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules and biological polymers that are released during membrane trafficking events such as the secretory, endocytic, autophagic, and phagocytic pathways. The degradation is carried out by several hydrolytic enzymes active in an acidic environment of the lysosomal lumen. These acid hydrolases are involved in cellular processes such as cell signaling,...
25.0K
01:36Delivery Pathways to the Lysosome
8.6K
Eukaryotic cells use different mechanisms to eliminate toxic waste obsolete and worn-out substances. Lysosomes play a pivotal role in this, and hence, these substances are carried to the lysosome from other parts of the cell and extracellular space through different pathways. The most elaborately studied pathways to the lysosome are the endocytic pathways.
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
8.6K
01:22Lysosomal Hydrolases
4.3K
Lysosomes are the site for the degradation of macromolecules and biological polymers released during membrane trafficking events such as secretory, endocytic, autophagic, and phagocytic pathways. The membrane-enclosed area of the lysosome, called the lumen, contains hydrolytic enzymes active in an acidic environment. These acid hydrolases are functional at a pH between 4.5 and 5 and are involved in cellular processes such as cell signaling, energy metabolism, restoration of the plasma membrane,...
4.3K
01:27Autophagy
5.5K
Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
5.5K
01:32Export of Misfolded Proteins out of the ER
4.8K
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
4.8K
01:02Long-patch Base Excision Repair
7.7K
Since the discovery of the two BER pathways, there has been a debate about how a cell chooses one pathway over the other and the factors determining this selection. Numerous in vitro experiments have pointed out multiple determinants for the sub-pathway selection. These are:
7.7K