Related Experiment Video
Updated: Jun 17, 2025
09:04
Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation
Published on: September 7, 2010
11.6K
Cellular translocation and secretion of sialidases
Majdi A Aljohani1, Hiroaki Sasaki2, Xue-Long Sun3
1Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation in Health and Disease (GRHD), Cleveland State University, Cleveland, Ohio, USA; Faculty of Applied Medical Sciences, Department of Medical Laboratory Technology, University of Tabuk, Tabuk, Saudi Arabia.
The Journal of Biological Chemistry
|August 11, 2024
Summary
Sialidases, enzymes that remove sialic acid, can move within cells or be secreted. This translocation and secretion impact cell function and are vital in health and disease.
Area of Science:
- Biochemistry
- Cell Biology
- Glycobiology
Background:
- Sialidases (neuraminidases) remove sialic acid from glycans, modulating glycoprotein and glycolipid function.
- Mammalian cells express four sialidases (Neu1, Neu2, Neu3, Neu4) with distinct subcellular localizations and substrate specificities.
- Sialidase localization can change dynamically within cells under specific conditions, influencing cellular processes.
Purpose of the Study:
- To review recent advances in understanding sialidase translocation and secretion.
- To explore the involvement of sialidases in various physiological and pathological pathways.
Main Methods:
- Literature review of studies on sialidase behavior and function.
- Analysis of cellular conditions and stimuli affecting sialidase translocation and secretion.
- Examination of the impact of sialidase activity on biological pathways.
Main Results:
- Sialidases can translocate between subcellular compartments, such as lysosomal sialidase Neu1 moving to the cell surface.
- Activated cells secrete sialidases, enabling extracellular desialylation of cell-associated and soluble molecules.
- Dynamic localization and secretion of sialidases contribute to diverse cellular functions and disease mechanisms.
Conclusions:
- Sialidase translocation and secretion are critical regulatory mechanisms.
- Understanding these processes offers insights into the roles of sialidases in health and disease.
- Further research into sialidase dynamics can reveal novel therapeutic targets.
Related Concept Videos
01:33Overview of Secretory Vesicles
8.5K
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
8.5K
01:23Transcellular Transport of Solutes
3.5K
Transcellular transport of solutes is the movement of substances like monosaccharides and amino acids through polarized cells. This transport mechanism is primarily seen in epithelial and endothelial cells aided by membrane transport proteins such as channels and transporters. The tight junctions between these cells confine the membrane proteins to the two sides of the cell. The epithelial cells have distinct apical and basolateral domains. In contrast, the endothelial cells show the luminal...
3.5K
01:28Protein Translocation Machinery on the ER Membrane
4.6K
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
4.6K
01:27Post-translational Translocation of Proteins to the RER
5.7K
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
5.7K
01:05Insulin Secretory Vesicles
4.9K
Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
4.9K
01:32Export of Misfolded Proteins out of the ER
3.6K
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...
3.6K