Caspase 1 is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that proteolytically

Proteolysis

Proteolysis is the directed degradation of proteins by cellular enzymes called proteases or by intramolecular digestion.-Purposes:Proteolysis is used by the cell for several purposes...

 cleaves other proteins, such as the precursor

Protein precursor

A protein precursor, also called a pro-protein or pro-peptide, is an inactive protein that can be turned into an active form by posttranslational modification. The name of the precursor for a protein is often prefixed by pro...

 forms of the inflammatory cytokine

Cytokine

Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

s interleukin 1-β and interleukin 18

Interleukin 18

Interleukin-18 also known as IL18 is a protein which in humans is encoded by the IL18 gene. The protein encoded by this gene is a proinflammatory cytokine.- Function :...

, into active mature peptides. It belongs to a family of cysteine protease

Cysteine protease

Proteases are enzymes that degrade polypeptides. Cysteine proteases have a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic dyad. The first step is deprotonation of a thiol in the enzyme's active site by an adjacent amino acid with a basic side chain, usually a...

s known as caspase

Caspase

Caspases, or cysteine-aspartic proteases or cysteine-dependent aspartate-directed proteases are a family of cysteine proteases that play essential roles in apoptosis , necrosis, and inflammation....

s that always cleave proteins following an aspartic acid

Aspartic acid

Aspartic acid is an α-amino acid with the chemical formula HOOCCHCH2COOH. The carboxylate anion, salt, or ester of aspartic acid is known as aspartate. The L-isomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins...

 residue.
Caspase 1 is produced as a zymogen

Zymogen

A zymogen is an inactive enzyme precursor. A zymogen requires a biochemical change for it to become an active enzyme. The biochemical change usually occurs in a lysosome where a specific part of the precursor enzyme is cleaved in order to activate it...

 that is cleaved into 20 kDa (p20) and 10 kDa (p10) subunits that become part of the active enzyme. Active caspase 1 contains two heterodimers of p20 and p10. It interacts with another CARD domain

CARD domain

Caspase recruitment domains, or Caspase activation and recruitment domains , are interaction motifs found in a wide array of proteins, typically those involved in processes relating to inflammation and apoptosis. These domains mediate the formation of larger protein complexes via direct...

 containing protein called PYCARD

PYCARD

Apoptosis-associated speck-like protein containing a CARD or ASC is a protein that in humans is encoded by the PYCARD gene.This gene encodes an adaptor protein that is composed of two protein–protein interaction domains: a N-terminal PYRIN-PAAD-DAPIN domain and a C-terminal caspase-recruitment...

 (or ASC) and is involved in inflammasome

Inflammasome

The inflammasome is a multiprotein oligomer consisting of caspase 1, PYCARD, NALP and sometimes caspase 5 . It is expressed in myeloid cells and is a component of the innate immune system. The exact composition of an inflammasome depends on the activator which initiates inflammasome assembly i.e...

 formation and activation of inflammatory

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 processes.

Caspase 1 has been shown to induce cell necrosis

Necrosis

Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

 or pyroptosis

Pyroptosis

Pyroptosis is a form of programmed cell death associated with antimicrobial responses during inflammation. In contrast to apoptosis, pyroptosis requires the function of caspase-1, and has been studied in the context of salmonella-infected macrophages....

 and may function in various developmental stages. Studies of a similar protein in mouse suggest a role in the pathogenesis of Huntington's disease

Huntington's disease

Huntington's disease, chorea, or disorder , is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable in middle age. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea...

. Alternative splicing

Alternative splicing

Alternative splicing is a process by which the exons of the RNA produced by transcription of a gene are reconnected in multiple ways during RNA splicing...

 of the gene results in five transcript variants encoding distinct isoforms.

Interactions

Caspase 1 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with NLRC4

NLRC4

NLR family CARD domain-containing protein 4 is a protein that in humans is encoded by the NLRC4 gene.-Interactions:NLRC4 has been shown to interact with caspase 1 and NOD2.-Further reading:...

.

External links

• The MEROPS
  Merops
  Merops may refer to:* Merops , a genus of bee-eaters.* MEROPS, an on-line database for peptidases.It may also refer to several figures from Greek mythology:* King of Ethiopia, husband of Clymene, who lay with Helios and bore Phaethon...
  
  online database for peptidases and their inhibitors: C14.001