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Review
. 2001 Apr;107(8):929-34.
doi: 10.1172/JCI12749.

Thrombospondins as matricellular modulators of cell function

P Bornstein  1
Affiliations
Review

Thrombospondins as matricellular modulators of cell function

P Bornstein. J Clin Invest. 2001 Apr.
No abstract available

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Figures

Figure 1
Figure 1
A proposed scheme to account for the modulation of pericellular MMP2 levels by TSP2. TSP2, ProMMP2, and TIMP2 are secreted into the pericellular environment, either individually or together, by fusion of secretory vesicles with the plasma membrane (double line). As shown on the right side of the figure, ProMMP2, in a complex with TIMP2, can be activated by membrane-bound MT1-MMP to form active MMP2, which is capable of reducing adhesion by cleaving matrix-bound proteins and proteoglycans, and possibly adhesion receptors. When TSP2 is present, a competing pathway clears ProMMP2 from the cell surface. Thus, as shown on the left, TSP2 can bind either ProMMP2 or active MMP2. This complex is then bound by the LRP receptor, endocytosed, and directed to lysosomes for degradation. Since the binding of (Pro)MMP2 to TIMP2 is of considerably higher affinity than that to TSP2, it is possible that a trimolecular complex that includes TIMP2 is endocytosed by LRP. However, TSP2 could still compete effectively with TIMP2 for binding to ProMMP2 or MMP2 by mass action, if the [TSP2] >> [(Pro)MMP2] and if the TSP2/(Pro)MMP2 complex were constantly removed by endocytosis. Alternatively, the TSP2/(Pro)MMP2 complex could be bound to the matrix, thus reducing the bioavailability of the protease.
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References

    1. Bornstein P, Sage EH. Thrombospondins. Methods Enzymol. 1994;245:62–85. - PubMed
    1. Bornstein P. Diversity of function is inherent in matricellular proteins: an appraisal of thrombospondin 1. J Cell Biol. 1995;130:503–506. - PMC - PubMed
    1. Hynes RO, Zhao Q. The evolution of cell adhesion. J Cell Biol. 2000;150:F89–F95. - PubMed
    1. Kyriakides TR, et al. Mice that lack thrombospondin 2 display connective tissue abnormalities that are associated with disordered collagen fibrillogenesis, an increased vascular density, and a bleeding diathesis. J Cell Biol. 1998;140:419–430. - PMC - PubMed
    1. Lawler J, et al. Thrombospondin-1 is required for normal murine pulmonary homeostasis and its absence causes pneumonia. J Clin Invest. 1998;101:982–992. - PMC - PubMed

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