Modulation of the proteolytic activity of matrix metalloproteinase-2 (gelatinase A) on fibrinogen

Abstract

The proteolytic processing of bovine fibrinogen by MMP-2 (gelatinase A), which brings about the formation of a product unable to form fibrin clots, has been studied at 37 degrees C. Catalytic parameters, although showing a somewhat lower catalytic efficiency with respect to thrombin and plasmin, indeed display values indicating a pathophysiological significance of this process. A parallel molecular modelling study predicts preferential binding of MMP-2 to the beta-chain of fibrinogen through its haemopexin-like domain, which has been directly demonstrated by the inhibitory effect in the presence of the exogenous haemopexin-like domain. However, the removal of this domain does not impair the interaction between MMP-2 and fibrinogen, but it dramatically alters the proteolytic mechanism, producing different fragmentation intermediates. The investigation at various pH values between 6.0 and 9.3 indicates a proton-linked behaviour, which is relevant for interpreting the influence on the process by environmental conditions occurring at the site of an injury. Furthermore, the action of MMP-2 on peroxynitrite-treated fibrinogen has been investigated, a situation possibly occurring under oxidative stress. The chemical alteration of fibrinogen, which has been shown to abolish its clotting activity, brings about only limited modifications of the catalytic parameters without altering the main enzymatic mechanism.

Hemopexin domains as multifunctional liganding modules in matrix metalloproteinases and other proteins

“…Fragmentation of fibrinogen occurs at a 20-fold lower rate by a gelatinase A/MMP-2 variant without hemopexin domain than by the intact proteinase, and an additional fibrinogen fragment, which is not observed upon cleavage by full-length gelatinase A/MMP-2, is formed. These findings implicate a role for the hemopexin domain of gelatinase A/MMP-2 in (correct) recognition of fibrinogen [149]. Also, the catalytic domains of neutrophil collagenase-2/MMP-8, metalloelastase/MMP-12, collagenase-3/MMP-13, and MT1-MMP/MMP-14 are shown to cleave fibrinogen [150].…”

Protons make tumor cells move like clockwork

“…Human MMP-3 (=stromelysin-1) shows its maximum activity in a narrow range of pH values ranging from pH 5.75 to 6.25 [45]. While MMP-3 activity depends on its own protonation, the extent to which the substrate such as fibrinogen is protonated also affects MMP activity as shown for MMP-2 [83]. Hence, protonation of the protease itself or protonation of the protein structures of the extracellular matrix to be cleaved depends on the local pH homeostasis.…”

Ion channels and transporters in tumour cell migration and invasion

“…B 369: 20130102 pH-dependent proteases [28, 95,96]. The activity of matrix metalloproteinase 2 (MMP2) requires the protonation of the substrate such as fibrinogen [97], and the expression of MMP9 is upregulated by an acidic extracellular pH [98]. Invasive behaviour of various tumour cells is also triggered by the expression of voltage-gated Na þ channels (Na V ) [99].…”