1
|
Lee AA, Kim NH, Alvarez S, Ren H, DeGrandchamp JB, Lew LJN, Groves JT. Bimodality in Ras signaling originates from processivity of the Ras activator SOS without deterministic bistability. SCIENCE ADVANCES 2024; 10:eadi0707. [PMID: 38905351 PMCID: PMC11192083 DOI: 10.1126/sciadv.adi0707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 05/15/2024] [Indexed: 06/23/2024]
Abstract
Ras is a small GTPase that is central to important functional decisions in diverse cell types. An important aspect of Ras signaling is its ability to exhibit bimodal or switch-like activity. We describe the total reconstitution of a receptor-mediated Ras activation-deactivation reaction catalyzed by SOS and p120-RasGAP on supported lipid membrane microarrays. The results reveal a bimodal Ras activation response, which is not a result of deterministic bistability but is rather driven by the distinct processivity of the Ras activator, SOS. Furthermore, the bimodal response is controlled by the condensation state of the scaffold protein, LAT, to which SOS is recruited. Processivity-driven bimodality leads to stochastic bursts of Ras activation even under strongly deactivating conditions. This behavior contrasts deterministic bistability and may be more resistant to pharmacological inhibition.
Collapse
Affiliation(s)
- Albert A. Lee
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Neil H. Kim
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Steven Alvarez
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - He Ren
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | | | - L. J. Nugent Lew
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Jay T. Groves
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| |
Collapse
|
2
|
Madrigal J, Monroe DM, Sindi SS, Leiderman K. Modeling the distribution of enzymes on lipid vesicles: A novel framework for surface-mediated reactions in coagulation. Math Biosci 2024; 374:109229. [PMID: 38851530 DOI: 10.1016/j.mbs.2024.109229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 06/02/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024]
Abstract
Blood coagulation is a network of biochemical reactions wherein dozens of proteins act collectively to initiate a rapid clotting response. Coagulation reactions are lipid-surface dependent, and this dependence is thought to help localize coagulation to the site of injury and enhance the association between reactants. Current mathematical models of coagulation either do not consider lipid as a variable or do not agree with experiments where lipid concentrations were varied. Since there is no analytic rate law that depends on lipid, only apparent rate constants can be derived from enzyme kinetic experiments. We developed a new mathematical framework for modeling enzymes reactions in the presence of lipid vesicles. Here the concentrations are such that only a fraction of the vesicles harbor bound enzymes and the rest remain empty. We call the lipid vesicles with and without enzyme TF:VIIa+ and TF:VIIa- lipid, respectively. Since substrate binds to both TF:VIIa+ and TF:VIIa- lipid, our model shows that excess empty lipid acts as a strong sink for substrate. We used our framework to derive an analytic rate equation and performed constrained optimization to estimate a single, global set of intrinsic rates for the enzyme-substrate pair. Results agree with experiments and reveal a critical lipid concentration where the conversion rate of the substrate is maximized, a phenomenon known as the template effect. Next, we included product inhibition of the enzyme and derived the corresponding rate equations, which enables kinetic studies of more complex reactions. Our combined experimental and mathematical study provides a general framework for uncovering the mechanisms by which lipid mediated reactions impact coagulation processes.
Collapse
Affiliation(s)
- Jamie Madrigal
- Mathematics Department, University of North Carolina at Chapel Hill, Chapel Hill, 27599-3250, NC, USA
| | - Dougald M Monroe
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Suzanne S Sindi
- Mathematics Department, University of California Merced, Merced, CA, USA
| | - Karin Leiderman
- Mathematics Department, University of North Carolina at Chapel Hill, Chapel Hill, 27599-3250, NC, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| |
Collapse
|
3
|
Fung SYS, Xǔ XJ, Wu M. Nonlinear dynamics in phosphoinositide metabolism. Curr Opin Cell Biol 2024; 88:102373. [PMID: 38797149 PMCID: PMC11186694 DOI: 10.1016/j.ceb.2024.102373] [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: 02/09/2024] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/29/2024]
Abstract
Phosphoinositides broadly impact membrane dynamics, signal transduction and cellular physiology. The orchestration of signaling complexity by this seemingly simple metabolic pathway remains an open question. It is increasingly evident that comprehending the complexity of the phosphoinositides metabolic network requires a systems view based on nonlinear dynamics, where the products of metabolism can either positively or negatively modulate enzymatic function. These feedback and feedforward loops may be paradoxical, leading to counterintuitive effects. In this review, we introduce the framework of nonlinear dynamics, emphasizing distinct dynamical regimes such as the excitable state, oscillations, and mixed-mode oscillations-all of which have been experimentally observed in phosphoinositide metabolisms. We delve into how these dynamical behaviors arise from one or multiple network motifs, including positive and negative feedback loops, coherent and incoherent feedforward loops. We explore the current understanding of the molecular circuits responsible for these behaviors. While mapping these circuits presents both conceptual and experimental challenges, redefining cellular behavior based on dynamical state, lipid fluxes, time delay, and network topology is likely essential for a comprehensive understanding of this fundamental metabolic network.
Collapse
Affiliation(s)
- Suet Yin Sarah Fung
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA
| | - X J Xǔ
- Department of Physics, Yale University, New Haven, CT, 06511, USA
| | - Min Wu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA.
| |
Collapse
|
4
|
Leonard TA, Loose M, Martens S. The membrane surface as a platform that organizes cellular and biochemical processes. Dev Cell 2023; 58:1315-1332. [PMID: 37419118 DOI: 10.1016/j.devcel.2023.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/22/2023] [Accepted: 06/08/2023] [Indexed: 07/09/2023]
Abstract
Membranes are essential for life. They act as semi-permeable boundaries that define cells and organelles. In addition, their surfaces actively participate in biochemical reaction networks, where they confine proteins, align reaction partners, and directly control enzymatic activities. Membrane-localized reactions shape cellular membranes, define the identity of organelles, compartmentalize biochemical processes, and can even be the source of signaling gradients that originate at the plasma membrane and reach into the cytoplasm and nucleus. The membrane surface is, therefore, an essential platform upon which myriad cellular processes are scaffolded. In this review, we summarize our current understanding of the biophysics and biochemistry of membrane-localized reactions with particular focus on insights derived from reconstituted and cellular systems. We discuss how the interplay of cellular factors results in their self-organization, condensation, assembly, and activity, and the emergent properties derived from them.
Collapse
Affiliation(s)
- Thomas A Leonard
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria; Medical University of Vienna, Center for Medical Biochemistry, Dr. Bohr-Gasse 9, 1030, Vienna, Austria.
| | - Martin Loose
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
| | - Sascha Martens
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria; University of Vienna, Center for Molecular Biology, Department of Biochemistry and Cell Biology, Dr. Bohr-Gasse 9, 1030, Vienna, Austria.
| |
Collapse
|
5
|
Lee AA, Kim NH, Alvarez S, Ren H, DeGrandchamp JB, Lew LJN, Groves JT. Bimodality in Ras signaling originates from processivity of the Ras activator SOS without classic kinetic bistability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549263. [PMID: 37503094 PMCID: PMC10370109 DOI: 10.1101/2023.07.17.549263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Ras is a small GTPase that is central to important functional decisions in diverse cell types. An important aspect of Ras signaling is its ability to exhibit bimodal, or switch-like activity. We describe the total reconstitution of a receptor-mediated Ras activation-deactivation reaction catalyzed by SOS and p120-RasGAP on supported lipid membrane microarrays. The results reveal a bimodal Ras activation response, which is not a result of classic kinetic bistability, but is rather driven by the distinct processivity of the Ras activator, SOS. Furthermore, the bimodal response is controlled by the condensation state of the scaffold protein, LAT, to which SOS is recruited. Processivity-driven bimodality leads to stochastic bursts of Ras activation even under strongly deactivating conditions. This behavior contrasts classic kinetic bistability and is distinctly more resistant to pharmacological inhibition.
Collapse
|
6
|
Roveri A, Di Giacinto F, Rossetto M, Cozza G, Cheng Q, Miotto G, Zennaro L, Di Paolo ML, Arnér ESJ, De Spirito M, Maiorino M, Ursini F. Cardiolipin drives the catalytic activity of GPX4 on membranes: Insights from the R152H mutant. Redox Biol 2023; 64:102806. [PMID: 37413766 DOI: 10.1016/j.redox.2023.102806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023] Open
Abstract
The aim of this study was to examine, in biochemical detail, the functional role of the Arg152 residue in the selenoprotein Glutathione Peroxidase 4 (GPX4), whose mutation to His is involved in Sedaghatian-type Spondylometaphyseal Dysplasia (SSMD). Wild-type and mutated recombinant enzymes with selenopcysteine (Sec) at the active site, were purified and structurally characterized to investigate the impact of the R152H mutation on enzymatic function. The mutation did not affect the peroxidase reaction's catalytic mechanism, and the kinetic parameters were qualitatively similar between the wild-type enzyme and the mutant when mixed micelles and monolamellar liposomes containing phosphatidylcholine and its hydroperoxide derivatives were used as substrate. However, in monolamellar liposomes also containing cardiolipin, which binds to a cationic area near the active site of GPX4, including residue R152, the wild-type enzyme showed a non-canonical dependency of the reaction rate on the concentration of both enzyme and membrane cardiolipin. To explain this oddity, a minimal model was developed encompassing the kinetics of both the enzyme interaction with the membrane and the catalytic peroxidase reaction. Computational fitting of experimental activity recordings showed that the wild-type enzyme was surface-sensing and prone to "positive feedback" in the presence of cardiolipin, indicating a positive cooperativity. This feature was minimal, if any, in the mutant. These findings suggest that GPX4 physiology in cardiolipin containing mitochondria is unique, and emerges as a likely target of the pathological dysfunction in SSMD.
Collapse
Affiliation(s)
| | - Flavio Di Giacinto
- Neuroscience Department, Biophysics Section, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Monica Rossetto
- Department of Molecular Medicine, University of Padova, Italy
| | - Giorgio Cozza
- Department of Molecular Medicine, University of Padova, Italy
| | - Qing Cheng
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17177, Sweden
| | - Giovanni Miotto
- Department of Molecular Medicine, University of Padova, Italy
| | - Lucio Zennaro
- Department of Molecular Medicine, University of Padova, Italy
| | | | - Elias S J Arnér
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17177, Sweden; Department of Selenoprotein Research and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary
| | - Marco De Spirito
- Neuroscience Department, Biophysics Section, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Fulvio Ursini
- Department of Molecular Medicine, University of Padova, Italy.
| |
Collapse
|
7
|
Kotzampasi DM, Premeti K, Papafotika A, Syropoulou V, Christoforidis S, Cournia Z, Leondaritis G. The orchestrated signaling by PI3Kα and PTEN at the membrane interface. Comput Struct Biotechnol J 2022; 20:5607-5621. [PMID: 36284707 PMCID: PMC9578963 DOI: 10.1016/j.csbj.2022.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/16/2022] Open
Abstract
The oncogene PI3Kα and the tumor suppressor PTEN represent two antagonistic enzymatic activities that regulate the interconversion of the phosphoinositide lipids PI(4,5)P2 and PI(3,4,5)P3 in membranes. As such, they are defining components of phosphoinositide-based cellular signaling and membrane trafficking pathways that regulate cell survival, growth, and proliferation, and are often deregulated in cancer. In this review, we highlight aspects of PI3Kα and PTEN interplay at the intersection of signaling and membrane trafficking. We also discuss the mechanisms of PI3Kα- and PTEN- membrane interaction and catalytic activation, which are fundamental for our understanding of the structural and allosteric implications on signaling at the membrane interface and may aid current efforts in pharmacological targeting of these proteins.
Collapse
Affiliation(s)
- Danai Maria Kotzampasi
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
- Department of Biology, University of Crete, Heraklion 71500, Greece
| | - Kyriaki Premeti
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Alexandra Papafotika
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Vasiliki Syropoulou
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Savvas Christoforidis
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Zoe Cournia
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
| | - George Leondaritis
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
- Institute of Biosciences, University Research Center of Ioannina, Ioannina 45110, Greece
| |
Collapse
|
8
|
Hansen SD, Lee AA, Duewell BR, Groves JT. Membrane-mediated dimerization potentiates PIP5K lipid kinase activity. eLife 2022; 11:73747. [PMID: 35976097 PMCID: PMC9470164 DOI: 10.7554/elife.73747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 08/16/2022] [Indexed: 11/28/2022] Open
Abstract
The phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family of lipid-modifying enzymes generate the majority of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] lipids found at the plasma membrane in eukaryotic cells. PI(4,5)P2 lipids serve a critical role in regulating receptor activation, ion channel gating, endocytosis, and actin nucleation. Here, we describe how PIP5K activity is regulated by cooperative binding to PI(4,5)P2 lipids and membrane-mediated dimerization of the kinase domain. In contrast to constitutively dimeric phosphatidylinositol 5-phosphate 4-kinase (PIP4K, type II PIPK), solution PIP5K exists in a weak monomer–dimer equilibrium. PIP5K monomers can associate with PI(4,5)P2-containing membranes and dimerize in a protein density-dependent manner. Although dispensable for cooperative PI(4,5)P2 binding, dimerization enhances the catalytic efficiency of PIP5K through a mechanism consistent with allosteric regulation. Additionally, dimerization amplifies stochastic variation in the kinase reaction velocity and strengthens effects such as the recently described stochastic geometry sensing. Overall, the mechanism of PIP5K membrane binding creates a broad dynamic range of lipid kinase activities that are coupled to the density of PI(4,5)P2 and membrane-bound kinase.
Collapse
Affiliation(s)
- Scott D Hansen
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, United States
| | - Albert A Lee
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Benjamin R Duewell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, United States
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| |
Collapse
|
9
|
A two-component protein condensate of the EGFR cytoplasmic tail and Grb2 regulates Ras activation by SOS at the membrane. Proc Natl Acad Sci U S A 2022; 119:e2122531119. [PMID: 35507881 PMCID: PMC9181613 DOI: 10.1073/pnas.2122531119] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SignificanceTwo-dimensional condensates of proteins on the membrane surface, driven by tyrosine phosphorylation, are beginning to emerge as important players in signal transduction. This work describes discovery of a protein condensation phase transition of EGFR and Grb2 on membrane surfaces, which is poised to have a significant impact on how we understand EGFR signaling and misregulation in disease. EGFR condensation is mediated through a Grb2-Grb2 crosslinking element, which itself is regulatable through a specific phosphotyrosine site on Grb2. Furthermore, the EGFR condensate exerts significant control over the ability of SOS to activate Ras, thus implicating the EGFR condensate as a regulator of signal propagation from EGFR to Ras and the MAPK pathway.
Collapse
|