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Torres-Paris C, Song HJ, Engelberger F, Ramírez-Sarmiento CA, Komives EA. The Light Chain Allosterically Enhances the Protease Activity of Murine Urokinase-Type Plasminogen Activator. Biochemistry 2024; 63:1434-1444. [PMID: 38780522 PMCID: PMC11154964 DOI: 10.1021/acs.biochem.4c00071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
The active form of the murine urokinase-type plasminogen activator (muPA) is formed by a 27-residue disordered light chain connecting the amino-terminal fragment (ATF) with the serine protease domain. The two chains are tethered by a disulfide bond between C1CT in the disordered light chain and C122CT in the protease domain. Previous work showed that the presence of the disordered light chain affected the inhibition of the protease domain by antibodies. Here we show that the disordered light chain induced a 3.7-fold increase in kcat of the protease domain of muPA. In addition, hydrogen-deuterium exchange mass spectrometry (HDX-MS) and accelerated molecular dynamics (AMD) were performed to identify the interactions between the disordered light chain and the protease domain. HDX-MS revealed that the light chain is contacting the 110s, the turn between the β10- and β11-strand, and the β7-strand. A reduction in deuterium uptake was also observed in the activation loop, the 140s loop and the 220s loop, which forms the S1-specificty pocket where the substrate binds. These loops are further away from where the light chain seems to be interacting with the protease domain. Our results suggest that the light chain most likely increases the activity of muPA by allosterically favoring conformations in which the specificity pocket is formed. We propose a model by which the allostery would be transmitted through the β-strands of the β-barrels to the loops on the other side of the protease domain.
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Affiliation(s)
- Constanza Torres-Paris
- Department
of Chemistry and Biochemistry, Mail Code 0309, University of California San Diego, 9325 S Scholars Dr, La Jolla, California 92161, United States
| | - Harriet J. Song
- Department
of Chemistry and Biochemistry, Mail Code 0309, University of California San Diego, 9325 S Scholars Dr, La Jolla, California 92161, United States
| | - Felipe Engelberger
- Institute
for Biological and Medical Engineering, Schools of Engineering, Medicine
and Biological Sciences, Pontificia Universidad
Católica de Chile, Santiago 7820436, Chile
- ANID
- Millennium Science Initiative Program - Millennium Institute for
Integrative Biology (iBio), Santiago 8331150, Chile
| | - César A. Ramírez-Sarmiento
- Institute
for Biological and Medical Engineering, Schools of Engineering, Medicine
and Biological Sciences, Pontificia Universidad
Católica de Chile, Santiago 7820436, Chile
- ANID
- Millennium Science Initiative Program - Millennium Institute for
Integrative Biology (iBio), Santiago 8331150, Chile
| | - Elizabeth A. Komives
- Department
of Chemistry and Biochemistry, Mail Code 0309, University of California San Diego, 9325 S Scholars Dr, La Jolla, California 92161, United States
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Misenheimer TM, Lasarev MR, Kumfer KT, Sheehan JP, Schwartz BS. A novel factor IXa-specific enzyme-linked immunosorbent assay detects factor IXa in human plasma. Res Pract Thromb Haemost 2024; 8:102338. [PMID: 38433974 PMCID: PMC10907220 DOI: 10.1016/j.rpth.2024.102338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/21/2023] [Accepted: 01/18/2024] [Indexed: 03/05/2024] Open
Abstract
Background Factor (F)IXa activity has been detected in human plasma and may impact thrombotic risk. Current FIXa activity assays are complex and cumbersome. Objectives To develop a reproducible enzyme-linked immunosorbent assay (ELISA) using a novel monoclonal antibody that detects total FIXa in human plasma. Methods A monoclonal antibody was raised against the new N-terminus exposed upon activation of FIX to FIXa by cleavage after R226. This antibody is specific for FIXa protease and does not recognize FIX zymogen or FIXα. The antibody was used to develop a FIXa-specific ELISA capable of quantifying total FIXa (free FIXa and FIXa-antithrombin complex) in human plasma. Total FIXa quantified using the ELISA was compared to that of FIXa-antithrombin quantified using modifications of a previously described ELISA. Results The FIXa-specific ELISA was reproducible and quantified total FIXa in human plasma. Total FIXa levels correlated with FIXa-antithrombin levels. Conclusion A monoclonal antibody was developed that specifically detects human FIXa protease. A FIXa-specific ELISA using the new antibody is capable of reproducibly measuring total FIXa in human plasma (both free FIXa and FIXa-antithrombin). This assay should facilitate the evaluation of total FIXa levels in a variety of clinical circumstances.
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Affiliation(s)
| | - Michael R. Lasarev
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Kraig T. Kumfer
- Morgridge Institute for Research, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - John P. Sheehan
- Department of Medicine/Hematology-Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- University of Wisconsin-Madison Carbone Cancer Center, Madison, Wisconsin, USA
| | - Bradford S. Schwartz
- Morgridge Institute for Research, Madison, Wisconsin, USA
- Departments of Medicine/Hematology-Oncology, and Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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Torres-Paris C, Chen Y, Xiao L, Song HJ, Chen P, Komives EA. The autoactivation of human single-chain urokinase-type plasminogen activator (uPA). J Biol Chem 2023; 299:105179. [PMID: 37607618 PMCID: PMC10520878 DOI: 10.1016/j.jbc.2023.105179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/29/2023] [Accepted: 08/15/2023] [Indexed: 08/24/2023] Open
Abstract
Most serine proteases are synthesized as inactive zymogens that are activated by cleavage by another protease in a tightly regulated mechanism. The urokinase-type plasminogen activator (uPA) and plasmin cleave and activate each other, constituting a positive feedback loop. How this mutual activation cycle begins has remained a mystery. We used hydrogen deuterium exchange mass spectrometry to characterize the dynamic differences between the inactive single-chain uPA (scuPA) and its active form two-chain uPA (tcuPA). The results show that the C-terminal β-barrel and the area around the new N terminus have significantly reduced dynamics in tcuPA as compared with scuPA. We also show that the zymogen scuPA is inactive but can, upon storage, become active in the absence of external proteases. In addition to plasmin, the tcuPA can activate scuPA by cleavage at K158, a process called autoactivation. Unexpectedly, tcuPA can cleave at position 158 even when this site is mutated. TcuPA can also cleave scuPA after K135 or K136 in the disordered linker, which generates the soluble protease domain of uPA. Plasmin cleaves scuPA exclusively after K158 and at a faster rate than tcuPA. We propose a mechanism by which the uPA receptor dimerization could promote autoactivation of scuPA on cell surfaces. These results resolve long-standing controversies in the literature surrounding the mechanism of uPA activation.
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Affiliation(s)
- Constanza Torres-Paris
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Yueyi Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Lufan Xiao
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Harriet J Song
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Pingyu Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
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Majumder R. Not so fast, antithrombin! Blood 2023; 141:1907-1908. [PMID: 37079331 PMCID: PMC10933703 DOI: 10.1182/blood.2023019793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
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Childers KC, Peters SC, Lollar P, Spencer HT, Doering CB, Spiegel PC. SAXS analysis of the intrinsic tenase complex bound to a lipid nanodisc highlights intermolecular contacts between factors VIIIa/IXa. Blood Adv 2022; 6:3240-3254. [PMID: 35255502 PMCID: PMC9198903 DOI: 10.1182/bloodadvances.2021005874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/27/2022] [Indexed: 11/20/2022] Open
Abstract
The intrinsic tenase (Xase) complex, formed by factors (f) VIIIa and fIXa, forms on activated platelet surfaces and catalyzes the activation of factor X to Xa, stimulating thrombin production in the blood coagulation cascade. The structural organization of the membrane-bound Xase complex remains largely unknown, hindering our understanding of the structural underpinnings that guide Xase complex assembly. Here, we aimed to characterize the Xase complex bound to a lipid nanodisc with biolayer interferometry (BLI), Michaelis-Menten kinetics, and small-angle X-ray scattering (SAXS). Using immobilized lipid nanodiscs, we measured binding rates and nanomolar affinities for fVIIIa, fIXa, and the Xase complex. Enzyme kinetic measurements demonstrated the assembly of an active enzyme complex in the presence of lipid nanodiscs. An ab initio molecular envelope of the nanodisc-bound Xase complex allowed us to computationally model fVIIIa and fIXa docked onto a flexible lipid membrane and identify protein-protein interactions. Our results highlight multiple points of contact between fVIIIa and fIXa, including a novel interaction with fIXa at the fVIIIa A1-A3 domain interface. Lastly, we identified hemophilia A/B-related mutations with varying severities at the fVIIIa/fIXa interface that may regulate Xase complex assembly. Together, our results support the use of SAXS as an emergent tool to investigate the membrane-bound Xase complex and illustrate how mutations at the fVIIIa/fIXa dimer interface may disrupt or stabilize the activated enzyme complex.
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Affiliation(s)
- Kenneth C Childers
- Department of Chemistry, Western Washington University, Bellingham, WA; and
| | - Shaun C Peters
- Department of Chemistry, Western Washington University, Bellingham, WA; and
| | - Pete Lollar
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Harold Trent Spencer
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Christopher B Doering
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Paul C Spiegel
- Department of Chemistry, Western Washington University, Bellingham, WA; and
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