Synaptobrevins are small integral membrane proteins of secretory vesicle

Vesicle (biology)

A vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of many different molecules. More technically, a vesicle is a small membrane-enclosed sack that can store or transport substances. Vesicles can form naturally because of the properties of lipid membranes , or...

s with molecular weight of 18 kilodalton (kDa) that are part of the vesicle-associated membrane protein (VAMP) family.

Synaptobrevin is one of the SNARE proteins involved in formation of the SNARE complexes.

Structure

Out of four α-helices of the core SNARE complex one is contributed by synaptobrevin, one by syntaxin

Syntaxin

Syntaxins are a family of membrane integrated Q-SNARE proteins participating in exocytosis.- Domains :Syntaxins possess a single C-terminal transmembrane domain, a SNARE domain , and an N-terminal regulatory domain ....

, and two by SNAP-25

SNAP-25

Synaptosomal-associated protein 25 is a protein that in humans is encoded by the SNAP25 gene. The SNAP-25 protein is a component of the SNARE complex, which is proposed to account for the specificity of membrane fusion and to directly execute fusion by forming a tight complex that brings the...

 (in neurons).

Function

SNARE proteins are the key components of the molecular machinery that drives fusion of membranes in exocytosis

Exocytosis

Exocytosis , also known as 'The peni-cytosis', is the durable process by which a cell directs the contents of secretory vesicles out of the cell membrane...

. Their function however is subject to fine tuning by various regulatory protein collectively referred to as SNARE masters.

Classification

In the Q/R nomenclature

Nomenclature

Nomenclature is a term that applies to either a list of names or terms, or to the system of principles, procedures and terms related to naming - which is the assigning of a word or phrase to a particular object or property...

 for organizing SNARE proteins, VAMP/synaptobrevin family members are classified as R-SNAREs, so named for the presence of an arginine

Arginine

Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...

 at a specific location within the primary sequence of the protein (as opposed to the SNARES of the target membrane, which contain a glutamine

Glutamine

Glutamine is one of the 20 amino acids encoded by the standard genetic code. It is not recognized as an essential amino acid but may become conditionally essential in certain situations, including intensive athletic training or certain gastrointestinal disorders...

 and are so named Q-SNARES). Synaptobrevin is classified as a V-SNARE in the V/T nomenclature, an alternative classification scheme in which SNARES are classified as V-SNARES and T-SNARES for their localization to vesicles

Vesicle (biology)

A vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of many different molecules. More technically, a vesicle is a small membrane-enclosed sack that can store or transport substances. Vesicles can form naturally because of the properties of lipid membranes , or...

 and target membranes, respectively.

Clinical significance

Synaptobrevin is degraded by tetanospasmin

Tetanospasmin

Tetanus toxin is an extremely potent neurotoxin produced by the vegetative cell of Clostridium tetani in anaerobic conditions, causing tetanus. It has no known function for clostridia in the soil environment where they are normally encountered. It is also called spasmogenic toxin, tetanospasmin or...

, a protein derived from the bacterium Clostridium tetani

Clostridium tetani

Clostridium tetani is a rod-shaped, anaerobic bacterium of the genus Clostridium. Like other Clostridium species, it is Gram-positive, and its appearance on a gram stain resembles tennis rackets or drumsticks. C. tetani is found as spores in soil or in the gastrointestinal tract of animals. C...

, which causes tetanus

Tetanus

Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...

. A related bacterium, Clostridium botulinum

Clostridium botulinum

Clostridium botulinum is a Gram-positive, rod-shaped bacterium that produces several toxins. The best known are its neurotoxins, subdivided in types A-G, that cause the flaccid muscular paralysis seen in botulism. It is also the main paralytic agent in botox. C. botulinum is an anaerobic...

, produces a namesake toxin

Botulinum toxin

Botulinum toxin is a protein produced by the bacterium Clostridium botulinum, and is considered the most powerful neurotoxin ever discovered. Botulinum toxin causes Botulism poisoning, a serious and life-threatening illness in humans and animals...

 that also hydrolyzes synaptobrevin.

Human proteins containing this domain

SEC22A

SEC22A

Vesicle-trafficking protein SEC22a is a protein that in humans is encoded by the SEC22A gene.-Further reading:...

; SEC22B

SEC22B

Vesicle-trafficking protein SEC22b is a protein that in humans is encoded by the SEC22B gene. SEC22B has been shown to interact with syntaxin 18.-Further reading:...

; SYBL1

SYBL1

Vesicle-associated membrane protein 7 is a protein that in humans is encoded by the VAMP7 gene.- Function :VAMP-7 is a transmembrane protein that is a member of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor family...

; VAMP1

VAMP1

Vesicle-associated membrane protein 1 is a protein that in humans is encoded by the VAMP1 gene.-Further reading:...

; VAMP2

VAMP2

Vesicle-associated membrane protein 2 is a protein that in humans is encoded by the VAMP2 gene.-Interactions:VAMP2 has been shown to interact with STX4, SNAP-25, SNAP23, STX1A and RABAC1.-Further reading:...

; VAMP3

VAMP3

Vesicle-associated membrane protein 3 is a protein that in humans is encoded by the VAMP3 gene.-Interactions:VAMP3 has been shown to interact with* BCAP31,* BVES,* SNAP23,* STX4,* STX6.-Further reading:...

; VAMP4

VAMP4

Vesicle-associated membrane protein 4 is a protein that in humans is encoded by the VAMP4 gene.-Interactions:VAMP4 has been shown to interact with AP1M1, STX6 and STX16.-Further reading:...

; VAMP5

VAMP5

Vesicle-associated membrane protein 5 also known as VAMP5 is a human gene which encodes a member of the synaptobrevin protein family.-Function:...

; VAMP8; YKT6

YKT6

Synaptobrevin homolog YKT6 is a protein that in humans is encoded by the YKT6 gene.-Further reading:...

;