Cytochrome c
Cytochrome c (CYCS, also known as HCS or CYC) is a small heme protein of the mitochondrion. It acts as a central component of the electron transport chain and, once released into the cytosol, helps to initiate apoptosis. Browse Assay Genie's current range of Cytochrome c research reagents below, or read on for the biology behind the target.
Cytochrome c has two well-described roles. In the mitochondrion it is a central component of the electron transport chain: the protein associates with the inner membrane, accepts electrons from cytochrome b and transfers them to the cytochrome oxidase complex. This makes it a routine reference point in studies of mitochondrial respiration.
Its second role is in apoptosis. Suppression of anti-apoptotic members, or activation of pro-apoptotic members, of the Bcl-2 family alters mitochondrial membrane permeability and results in release of cytochrome c into the cytosol. There, binding of cytochrome c to Apaf-1 triggers activation of caspase-9, which accelerates apoptosis by activating other caspases. Researchers therefore often use the cytosolic appearance of cytochrome c as a readout of mitochondrial-pathway apoptosis, and a cytochrome c antibody or cytochrome c ELISA kit is a common tool for following it.
The human cytochrome c protein is encoded by the CYCS gene (cytochrome c, somatic) and belongs to the cytochrome c family. Mouse and rat each carry an orthologous gene, Cycs. Mutations in the CYCS gene are associated with autosomal dominant nonsyndromic thrombocytopenia. Numerous processed pseudogenes of this gene are found throughout the human genome, which is worth bearing in mind when designing nucleic acid assays for the cytochrome c gene.
Release of cytochrome c into the cytosol and its binding to Apaf-1 lead to caspase-9 activation, making it a key marker of mitochondrial apoptosis.
Cytochrome c carries electrons from cytochrome b to the cytochrome oxidase complex as part of the mitochondrial electron transport chain.
Bcl-2 family activity alters mitochondrial membrane permeability, controlling whether cytochrome c is released into the cytosol.
Mutations in the CYCS gene are associated with autosomal dominant nonsyndromic thrombocytopenia, linking this protein to inherited platelet disease.
Cytochrome c shuttles electrons from cytochrome b to the cytochrome oxidase complex in the mitochondrial electron transport chain. When released into the cytosol it binds Apaf-1, triggering caspase-9 activation, which then activates other caspases and accelerates apoptosis.
The human gene is named CYCS (cytochrome c, somatic) by HGNC. Other symbols recorded for it are HCS and CYC. UniProt lists the protein simply as cytochrome c, and it belongs to the cytochrome c family.
Mouse and rat both have an orthologous gene, Cycs, so rodent models are commonly used. In humans, mutations in CYCS are associated with autosomal dominant nonsyndromic thrombocytopenia. Check the datasheet of any product for its validated reactivity.
Apoptosis regulators, caspases and Bcl-2 family members that act alongside cytochrome c in the mitochondrial cell death pathway.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P99999; product specifications from Assay Genie datasheets.