The serpin plasminogen activator inhibitor 1 (PAI-1) spon-taneously undergoes a massive structural change from a metastable and active conformation, with a solvent-accessible reactive center loop (RCL), to a stable, inactive, or latent conformation, with the RCL inserted into the central beta-sheet. Physiologically, conversion to the latent state is regulated by the binding of vitronectin, which hinders the latency transition rate approximately twofold. The molecular mechanisms lead-ing to this rate change are unclear. Here, we investigated the effects of vitronectin on the PAI-1 latency transition using all -atom path sampling simulations in explicit solvent. In simu-lated latency transitions of free PAI-1, the RCL is quite mobile as is the gate, the region that impedes RCL access to the central beta-sheet. This mobility allows the formation of a transient salt bridge that facilitates the transition; this finding rationalizes existing mutagenesis results. Vitronectin binding reduces RCL and gate mobility by allosterically rigidifying structural ele-ments over 40 angstrom away from the binding site, thus blocking transition to the latent conformation. The effects of vitronectin are propagated by a network of dynamically correlated residues including a number of conserved sites that were previously identified as important for PAI-1 stability. Simulations also revealed a transient pocket populated only in the vitronectin-bound state, corresponding to a cryptic drug-binding site identified by crystallography. Overall, these results shed new light on PAI-1 latency transition regulation by vitronectin and illustrate the potential of path sampling simulations for un-derstanding functional protein conformational changes and for facilitating drug discovery.

Long-range allostery mediates the regulation of plasminogen activator inhibitor-1 by cell adhesion factor vitronectin / Kihn, Kyle; Marchiori, Elisa; Spagnolli, Giovanni; Boldrini, Alberto; Terruzzi, Luca; Lawrence, Daniel A; Gershenson, Anne; Faccioli, Pietro; Wintrode, Patrick L. - In: JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 1083-351X. - 298:12(2022), p. 102652. [10.1016/j.jbc.2022.102652]

Long-range allostery mediates the regulation of plasminogen activator inhibitor-1 by cell adhesion factor vitronectin

Marchiori, Elisa;Spagnolli, Giovanni;Boldrini, Alberto;Faccioli, Pietro;
2022-01-01

Abstract

The serpin plasminogen activator inhibitor 1 (PAI-1) spon-taneously undergoes a massive structural change from a metastable and active conformation, with a solvent-accessible reactive center loop (RCL), to a stable, inactive, or latent conformation, with the RCL inserted into the central beta-sheet. Physiologically, conversion to the latent state is regulated by the binding of vitronectin, which hinders the latency transition rate approximately twofold. The molecular mechanisms lead-ing to this rate change are unclear. Here, we investigated the effects of vitronectin on the PAI-1 latency transition using all -atom path sampling simulations in explicit solvent. In simu-lated latency transitions of free PAI-1, the RCL is quite mobile as is the gate, the region that impedes RCL access to the central beta-sheet. This mobility allows the formation of a transient salt bridge that facilitates the transition; this finding rationalizes existing mutagenesis results. Vitronectin binding reduces RCL and gate mobility by allosterically rigidifying structural ele-ments over 40 angstrom away from the binding site, thus blocking transition to the latent conformation. The effects of vitronectin are propagated by a network of dynamically correlated residues including a number of conserved sites that were previously identified as important for PAI-1 stability. Simulations also revealed a transient pocket populated only in the vitronectin-bound state, corresponding to a cryptic drug-binding site identified by crystallography. Overall, these results shed new light on PAI-1 latency transition regulation by vitronectin and illustrate the potential of path sampling simulations for un-derstanding functional protein conformational changes and for facilitating drug discovery.
2022
12
Kihn, Kyle; Marchiori, Elisa; Spagnolli, Giovanni; Boldrini, Alberto; Terruzzi, Luca; Lawrence, Daniel A; Gershenson, Anne; Faccioli, Pietro; Wintrode, Patrick L
Long-range allostery mediates the regulation of plasminogen activator inhibitor-1 by cell adhesion factor vitronectin / Kihn, Kyle; Marchiori, Elisa; Spagnolli, Giovanni; Boldrini, Alberto; Terruzzi, Luca; Lawrence, Daniel A; Gershenson, Anne; Faccioli, Pietro; Wintrode, Patrick L. - In: JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 1083-351X. - 298:12(2022), p. 102652. [10.1016/j.jbc.2022.102652]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/376494
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