Fibronectin 1 (Plasma fibronectin) (pFN)

Plasma fibronectin (pFN) is a major soluble glycoprotein found in the blood, synthesized primarily by hepatocytes and secreted into the systemic circulation [UniProt P02751]. It functions as a critical mediator of hemostasis and wound healing by cross-linking with fibrin to stabilize blood clots and providing a provisional matrix for the migration of fibroblasts and endothelial cells [PubMed PMID: 28433440]. Beyond its role in tissue repair, pFN acts as an opsonin, facilitating the clearance of particulate matter and bacteria from the blood by the reticuloendothelial system [PubMed PMID: 3889644]. In clinical contexts, decreased levels of pFN are observed in patients with severe trauma, burns, or sepsis, often correlating with multi-organ failure [PubMed PMID: 6373145]. Conversely, pFN is utilized therapeutically in topical formulations to treat persistent corneal epithelial defects and other non-healing wounds [PubMed PMID: 2470446]. While distinct from the cellular fibronectin isoforms (EDA and EDB) typically targeted in cancer imaging and therapy, pFN remains a vital target for managing systemic inflammation and promoting regenerative processes.

Other names

Cold-insoluble globulinCIGFN1LETS proteinAntiglobulinSerum fibronectin

Plasma fibronectin acts by binding to various cell surface receptors, most notably the alpha-5 beta-1 integrin, and extracellular components such as collagen, heparin, and fibrin [PubMed PMID: 12700668]. These interactions facilitate cell adhesion, spreading, and migration, while also activating intracellular signaling cascades like the FAK and MAPK pathways that promote cell survival and proliferation [PubMed PMID: 11486029].