Fibronectin 120 kDa fragment (FN-120)

The Fibronectin 120 kDa fragment is a specific proteolytic cleavage product of Fibronectin 1 (FN1), often generated by the action of enzymes like chymotrypsin or matrix metalloproteinases (MMPs) (Pierschbacher et al., 1981; Homandberg et al., 1992). It is widely recognized as the central cell-binding domain (CCBD) of fibronectin because it encompasses the 7th through 11th type III repeats, including the crucial Arg-Gly-Asp (RGD) motif and the Pro-His-Ser-Arg-Asn (PHSRN) synergy site (Aota et al., 1994; Nagai et al., 1991). These motifs allow the fragment to bind with high affinity to the alpha-5 beta-1 integrin, facilitating essential cellular processes such as adhesion, spreading, and migration (Nagai et al., 1991). In disease states, particularly osteoarthritis, the accumulation of this 120 kDa fragment in the joint space acts as a potent damage-associated molecular pattern (DAMP), triggering the upregulation of pro-inflammatory cytokines and cartilage-degrading enzymes (Homandberg et al., 1992). In oncology, the fragment's interaction with integrins can influence tumor cell survival and metastatic potential, making the fragment-integrin axis a target for therapeutic intervention (Kapila et al., 1999). Drugs interacting with this pathway typically aim to block the binding of the fragment to its integrin receptors to inhibit pathological signaling (Stoop et al., 2001).

Other names

Central cell-binding domain of fibronectinCCBD120 kDa chymotryptic fragment of fibronectinCell-binding fragment of fibronectin

The fragment acts as an endogenous ligand for the alpha-5 beta-1 integrin receptor; therapeutic agents typically function as competitive antagonists or neutralizing antibodies to block this interaction (Nagai et al., 1991; Stoop et al., 2001).