MASP1
MASP1 (mannan-binding lectin serine protease 1, also known as MASP, Map44, MASP-3, MAP-1, CRARF and PRSS5) is a secreted serine protease of the complement system. It acts in the lectin pathway and, through its MASP-3 isoform, in activation of the alternative pathway. Browse Assay Genie's current range of MASP1 research reagents below, or read on for the biology behind the target.
MASP1 is a serine protease that contributes to complement, the protein cascade that drives phagocytosis and breakdown of pathogens and strengthens the adaptive immune response. The MASP1 gene encodes a component of the lectin pathway of complement activation. The protein is synthesised as a zymogen and is activated when it complexes with the pathogen recognition molecules of the lectin pathway, mannose-binding lectin and the ficolins.
MASP1 is not directly involved in complement activation. Instead it may act as an amplifier, either by cleaving complement C2 or by activating another complement serine protease, MASP2. The alternative complement pathway acts as an amplification loop that enhances the other complement pathways. The MASP-3 isoform specifically catalyses cleavage and activation of factor D (CFD), the protease that initiates the alternative pathway. The MASP1 protein is also able to cleave fibrinogen and factor XIII, so it may be involved in coagulation.
MASP1 belongs to the peptidase S1 family and is found both secreted and at the cell surface. HGNC places it among the serine proteases, the sushi domain containing proteins and the complement system activation components. Alternative splicing gives multiple transcript variants. One splice variant lacks the serine protease domain and functions as an inhibitor of the complement pathway. Earlier names for the gene refer to the C4/C2 activating component of Ra-reactive factor. Mouse and rat both carry a Masp1 ortholog.
MASP1 complexes with mannose-binding lectin and the ficolins, making it a key component for studying how pathogen recognition leads to complement activation.
The MASP-3 isoform cleaves and activates factor D, linking MASP1 to initiation of the alternative complement amplification loop.
MASP1 can cleave fibrinogen and factor XIII, so it is studied as a possible link between complement and coagulation.
A splice variant lacking the protease domain inhibits the complement pathway, which makes MASP1 transcripts relevant to regulation of innate immune responses.
MASP1 is a serine protease of the complement system. It is activated through complexes with mannose-binding lectin and the ficolins, and may amplify complement activation by cleaving C2 or activating MASP2. Its MASP-3 isoform activates factor D, which initiates the alternative pathway.
MASP1 is also called MASP, Map44, MASP-3, MAP-1, CRARF and PRSS5, and its full name is mannan-binding lectin serine protease 1. Alternative splicing produces several transcripts, including MASP-3 and a variant lacking the serine protease domain that inhibits the complement pathway.
Mouse and rat each have a Masp1 ortholog of the human gene. Researchers working in these species should check the datasheet of any product for its validated reactivity before use.
MASP2 and other complement lectin pathway proteases that work alongside MASP1 in innate immunity.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P48740; product specifications from Assay Genie datasheets.