TY - JOUR
T1 - Structural insight into the two-step mechanism of pai-1 inhibition by small molecule tm5484
AU - Sillen, Machteld
AU - Miyata, Toshio
AU - Vaughan, Douglas E.
AU - Strelkov, Sergei V.
AU - Declerck, Paul J.
N1 - Funding Information:
Funding: This research was funded by RESEARCH FOUNDATION–FLANDERS (FWO), grant number G072915N to P.J.D. and S.V.S.; M.S. is a recipient of a Ph.D. fellowship Fundamental Research of the RESEARCH FOUNDATION FLANDERS (FWO), grant number 11ZQ918N.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/2/2
Y1 - 2021/2/2
N2 - Plasminogen activator inhibitor-1 (PAI-1), a key regulator of the fibrinolytic system, is the main physiological inhibitor of plasminogen activators. By interacting with matrix components, including vitronectin (Vn), PAI-1 plays a regulatory role in tissue remodeling, cell migration, and intracellular signaling. Emerging evidence points to a role for PAI-1 in various pathological conditions, including cardiovascular diseases, cancer, and fibrosis. Targeting PAI-1 is therefore a promising therapeutic strategy in PAI-1-related pathologies. A class of small molecule inhibitors including TM5441 and TM5484, designed to bind the cleft in the central β-sheet A of PAI-1, showed to be potent PAI-1 inhibitors in vivo. However, their binding site has not yet been confirmed. Here, we report two X-ray crystallographic structures of PAI-1 in complex with TM5484. The structures revealed a binding site at the flexible joint region, which is distinct from the presumed binding site. Based on the structural analysis and biochemical data we propose a mechanism for the observed dose-dependent two-step mechanism of PAI-1 inhibition. By binding to the flexible joint region in PAI-1, TM5484 might restrict the structural flexibility of this region, thereby inducing a substrate form of PAI-1 followed by a conversion to an inert form.
AB - Plasminogen activator inhibitor-1 (PAI-1), a key regulator of the fibrinolytic system, is the main physiological inhibitor of plasminogen activators. By interacting with matrix components, including vitronectin (Vn), PAI-1 plays a regulatory role in tissue remodeling, cell migration, and intracellular signaling. Emerging evidence points to a role for PAI-1 in various pathological conditions, including cardiovascular diseases, cancer, and fibrosis. Targeting PAI-1 is therefore a promising therapeutic strategy in PAI-1-related pathologies. A class of small molecule inhibitors including TM5441 and TM5484, designed to bind the cleft in the central β-sheet A of PAI-1, showed to be potent PAI-1 inhibitors in vivo. However, their binding site has not yet been confirmed. Here, we report two X-ray crystallographic structures of PAI-1 in complex with TM5484. The structures revealed a binding site at the flexible joint region, which is distinct from the presumed binding site. Based on the structural analysis and biochemical data we propose a mechanism for the observed dose-dependent two-step mechanism of PAI-1 inhibition. By binding to the flexible joint region in PAI-1, TM5484 might restrict the structural flexibility of this region, thereby inducing a substrate form of PAI-1 followed by a conversion to an inert form.
KW - Cardiovascular disease
KW - Fibrinolysis
KW - PAI-1 inhibitor
KW - Plasminogen activator inhibitor 1
KW - Thrombolysis
KW - X-ray crystallography
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U2 - 10.3390/ijms22031482
DO - 10.3390/ijms22031482
M3 - Article
C2 - 33540702
AN - SCOPUS:85100113658
SN - 1422-0067
VL - 22
SP - 1
EP - 14
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
IS - 3
M1 - 1482
ER -
