Navigation Links
Vesicle


In cell biology, a vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid bilayer. Vesicles store, transport, or digest cellular products and wastes.

This biomembrane enclosing the vesicle is the same as that of the outer (cellular) membrane. Thus, because of the separation, the intravesicular environment can be made to be different from the cytosolic environment. Vesicles are a basic tool of the cell for organizing metabolism, transport, enzyme storage, as well as being chemical reaction chambers. Many vesicles are made in the Golgi apparatus, but also in the endoplasmic reticulum, or are made from parts of the plasma membrane.

Lysosomes (membrane-bound digestive vesicles) can digest macromolecules (break them down to small compounds) that were taken in from the outside of the cell by an endocytic vesicle. This is the basic way for a cell to feed (except for photosynthesis in plants, which don't have lysosomes). The membrane of the lysosome is impermeable for lysozyme, the enzyme that does the actual digestion, to protect the cell interior from being digested by its own enzyme. Lysosomes are made in the Golgi apparatus.

Neurons store neurotransmitters in synaptic vesicles located at presynaptic terminals.

Contents

Transport vesicles

Transport vesicles can move molecules between locations inside the cell, e.g., proteins from the endoplasmic reticulum to the Golgi apparatus, and from there to the outer cell membrane, where they are secreted. They do this by budding off from one compartment and joining to another.

Anterograde transport vesicles

These are forward-moving vesicles.

Retrograde transport vesicles

These vesicles move from later to earlier cisterna.

Vesicles can be used as reaction chambers for chemical reactions that could damage the cell if they would occur in the cytosol. For example, peroxisomes are detoxifiers of hydrogen peroxide (H2O2), a toxic byproduct of cell metabolism. Large storage vesicles are known as vacuoles.

Mechanisms

Assembly of a protein coat drives vesicle formation and selection of cargo molecules.

Vesicle coat

The vesicle coat serves to sculpt the curvature of a donor membrane, and to select specific proteins as cargo. It selects cargo proteins by binding to sorting signals . In this way the vesicle coat clusters selected membrane cargo proteins into nascent vesicle buds.

See also: micelle

External links


'"/>


(Date:6/22/2016)... Md. , June 22, 2016  The American College ... Trade Show Executive Magazine as one of the ... on May 25-27 at the Bellagio in Las ... on the highest percentage of growth in each of the ... of exhibiting companies and number of attendees. The 2015 ACMG ...
(Date:6/22/2016)... , June 22, 2016 On Monday, ... call to industry to share solutions for the Biometric ... U.S. Customs and Border Protection (CBP), explains that CBP ... are departing the United States , ... and to defeat imposters. Logo - ...
(Date:6/20/2016)... , June 20, 2016 Securus ... justice technology solutions for public safety, investigation, corrections ... the prisons involved, it has secured the final ... (DOC) facilities for Managed Access Systems (MAS) installed. ... additional facilities to be installed by October, 2016. ...
Breaking Biology News(10 mins):
Other biology definition