Anti-C9 antibody [53]

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

C9 also known as complement component 9 is a protein that plays an essential mechanical role in the complement system. It typically associates in the formation of the membrane attack complex (MAC). The C9 protein weighing around 71 kDa expresses in the liver and is secreted into the blood plasma. Alternative names like 'Cloud 9 capture' and 'C9 tag' often refer to research tools or motifs derived from the C9 protein rather than the protein itself. Researchers frequently study C9 in mouse models where its physiological roles can be explored.

Biological function summary

C9 participates in defending against pathogens. It joins other complement components like C5b C6 C7 and C8 to form the MAC complex which facilitates cell lysis by forming pores in the membrane of target cells. This action directly results in microbial cell destruction serving a critical immune function. C9 is not only part of the MAC complex but also holds significance due to its unique function as the last step in the formation of the pore influencing the efficacy of pathogen elimination.

Pathways

C9 functions primarily within the complement cascade which includes the classical and alternative pathways. Its role is in the terminal pathway segment that ultimately leads to the formation of the MAC and follows the activation of C5 which cleaves to produce C5b. This connection extends to proteins like C3 which is upstream in the cascade and significantly impacts the cascade's activation highlighting C9's function as an integral terminal component in these pathways.

Associated diseases and disorders

Mutations or deficits in C9 relate to an increased susceptibility to infections particularly those caused by Neisseria species. This association results directly from its important role in the MAC formation. Additionally deficiency of C9 links to autoimmune disorders where the immune response may be improperly regulated due to compromised MAC formation. Other complement components like C6 and C8 may also relate to these diseases due to their collaboration with C9 in forming the MAC illustrating the interconnectedness of these proteins within the immune response framework.