A tether is a form of cell surface protrusion, separated from the
cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...
after the application of low pulling forces to the
cell surface membrane. They are thin,
viscoelastic
In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ...
tubes which can be observed ''in vivo'' due to
shear flow caused by molecular bonds between
blood cells and vessel walls, for example.
In biochemistry, a tether is a molecule that carries one or two carbon intermediates from one active site to another. They are commonly used in
lipid synthesis,
gluconeogenesis
Gluconeogenesis (GNG) is a metabolic pathway that results in the biosynthesis of glucose from certain non-carbohydrate carbon substrates. It is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In verte ...
, and the conversion of pyruvate into Acetyl CoA via PDH complex. Common tethers are lipoate -lysine residue complex associated with dihydrolipoyl transacetylase, which is used for carrying hydroxyethyl from hydroxyethyl TPP. This compound forms Acetyl- CoA, a convergent molecule in metabolic pathways.
Another tether is biotin-lysine residue complex associated with pyruvate carboxylase, an enzyme which plays an important role in gluconeogenesis. It is involved in the production of oxaloacetate from pyruvate.
One of the biological tethers used in the synthesis of fats is a β- mercaptoethylamine-pantothenate complex associated with an acyl carrier protein.
References
{{DEFAULTSORT:Tether (Cell Biology)
Biochemistry
Cell biology