Related Experiment Video
Updated: May 22, 2026
08:59
Real-Time Fluorescent Measurement of Synaptic Functions in Models of Amyotrophic Lateral Sclerosis
Published on: July 16, 2021
Impaired proteasome function in sporadic amyotrophic lateral sclerosis
Edor Kabashi1, Jeffrey N Agar, Michael J Strong
1Department of Neurology/Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, Canada.
Summary
Proteasome function is impaired in sporadic Amyotrophic Lateral Sclerosis (ALS). This study found reduced proteasome activity and altered subunit composition in ALS spinal cord tissue, implicating proteasome dysfunction in ALS pathogenesis.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- The ubiquitin-proteasome system is crucial for protein quality control.
- This system is known to be compromised in familial forms of Amyotrophic Lateral Sclerosis (ALS).
Purpose of the Study:
- To investigate whether proteasome function is impaired in sporadic ALS.
- To compare proteasome function in spinal cord and cerebellum of ALS patients.
Main Methods:
- Proteasomal activities and subunit composition were analyzed in post-mortem spinal cord and cerebellum from sporadic ALS and control cases.
- Immunohistochemistry was used to assess proteasome subunit levels in motor neurons.
Main Results:
- Significant reductions in chymotrypsin-like, caspase-like, and trypsin-like proteasomal activities were observed in the thoracic spinal cord of ALS patients.
- Alterations in constitutive proteasome machinery and reduced proteasome levels specifically in motor neurons were noted.
- Proteasome function was preserved in the cerebellum, a clinically spared region.
Conclusions:
- Impaired proteasome function is a common feature in both familial and sporadic ALS.
- These findings suggest that proteasome dysfunction plays a significant role in the pathogenesis of ALS.
Related Concept Videos
01:13The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important among these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
02:18The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
01:24Parkinson Disease ll: Pathophysiology
Parkinson disease (PD) is a progressive neurodegenerative disorder primarily affecting movement, with additional non-motor features. Its pathophysiology involves complex interactions among genetic susceptibility, environmental exposures, and cellular dysfunction, including dopaminergic neuron loss, protein aggregation, and mitochondrial impairment.Selective NeurodegenerationA key feature is the degeneration of dopaminergic neurons in the substantia nigra pars compacta, leading to reduced...
01:22Lysosomal Hydrolases
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,...
03:03Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
03:03Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...