Tryptase (, ) is the most abundant secretory granule-derived
serine proteinase contained in
mast cell
A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a par ...
s and has been used as a marker for mast cell activation.
Club cell
Club cells, also known as bronchiolar exocrine cells, and formerly known as Clara cells, are low columnar/cuboidal cells with short microvilli, found in the small airways ( bronchioles) of the lungs.
Club cells are found in the ciliated simple e ...
s contain tryptase, which is believed to be responsible for cleaving the
hemagglutinin
In molecular biology, hemagglutinins (or ''haemagglutinin'' in British English) (from the Greek , 'blood' + Latin , 'glue') are receptor-binding membrane fusion glycoproteins produced by viruses in the ''Paramyxoviridae'' family. Hemagglutinins ar ...
surface protein of
influenza A
'' A virus'' (''IAV'') causes influenza in birds and some mammals, and is the only species of the genus ''Alphainfluenzavirus'' of the virus family '' Orthomyxoviridae''. Strains of all subtypes of influenza A virus have been isolated from wi ...
virus, thereby activating it and causing the symptoms of flu.
Nomenclature
Tryptase is also known by mast cell tryptase, mast cell protease II, skin tryptase, lung tryptase, pituitary tryptase, mast cell neutral proteinase, mast cell serine proteinase II, mast cell proteinase II, mast cell serine proteinase tryptase, rat mast cell protease II, and tryptase M.
Clinical use
Serum levels are normally less than 11.5 ng/mL. Elevated levels of serum tryptase occur in both
anaphylactic
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follow ...
and anaphylactoid reactions, but a negative test does not exclude
anaphylaxis
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follow ...
. Tryptase is less likely to be elevated in food allergy reactions as opposed to other causes of anaphylaxis. Serum tryptase levels are also elevated in and used as one indication suggesting the presence of
eosinophilic leukemias due to genetic mutations resulting in the formation of
''FIP1L1-PDGFRA'' fusion genes or the presence of
systemic mastocytosis
Mastocytosis, a type of mast cell disease, is a rare disorder affecting both children and adults caused by the accumulation of functionally defective mast cells (also called ''mastocytes'') and CD34+ mast cell precursors.
People affected by masto ...
.
Physiology
Tryptase is involved with allergenic response and is suspected to act as a
mitogen
A mitogen is a small bioactive protein or peptide that induces a cell to begin cell division, or enhances the rate of division (mitosis). Mitogenesis is the induction (triggering) of mitosis, typically via a mitogen. The mechanism of action of a ...
for
fibroblast
A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound ...
lines. Tryptase may use the
morpheein
Morpheeins are proteins that can form two or more different homo-oligomers (morpheein forms), but must come apart and change shape to convert between forms. The alternate shape may reassemble to a different oligomer. The shape of the subunit ...
model of
allosteric regulation
In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site.
The site to which the effector binds is termed the ''allosteric site ...
.
Mast cell tryptase-6 is involved in
Trichinella spiralis
''Trichinella spiralis'' is a viviparous nematode parasite, occurring in rodents, pigs, bears, hyenas and humans, and is responsible for the disease trichinosis. It is sometimes referred to as the "pork worm" due to it being typically encounte ...
infection in mice through linking
adaptive
Adaptation, in biology, is the process or trait by which organisms or population better match their environment
Adaptation may also refer to:
Arts
* Adaptation (arts), a transfer of a work of art from one medium to another
** Film adaptation, a ...
and
innate immunity
The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...
.
Genes
Human genes that encode proteins with tryptase activity include:
Mouse genes that encode proteins with tryptase activity include:
References
External links
*
EC 3.4.21
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