FibrinogenRelated

Fibrinogen-related refers to proteins or protein domains that are related to fibrinogen, particularly the fibrinogen-related domain (FReD). The FReD is a conserved extracellular module found in a broad range of metazoan proteins. It is typically about 200 amino acids long and can occur as a single domain or in tandem repeats, often linked to other modules such as immunoglobulin-like or lectin-like domains.

The term encompasses a diverse set of proteins across animals. In vertebrates, fibrinogen itself is a key coagulation factor involved in clot formation and wound repair. Other FReD-containing proteins, including ficolins and related lectins, participate in innate immunity by recognizing carbohydrate patterns and contributing to complement activation. In invertebrates, fibrinogen-related proteins (FREPs) act as immune effectors that bind pathogens and promote recognition, agglutination, or opsonization.

Evolutionarily, the FReD is an ancient module found in different lineages and shows considerable architectural diversity. It often appears in combination with other domains, enabling a range of functions from coagulation-related interactions to immune recognition. Comparative studies of FReD-containing proteins help clarify relationships among coagulation factors and immune receptors and illuminate how modular domains are repurposed over evolutionary time.

In research contexts, the term fibrinogen-related is used to describe protein families defined by this shared domain rather than a single biochemical activity. Understanding FReDs contributes to knowledge of coagulation biology, innate immunity, and the evolution of protein domains across species.