1
|
Ravala SK, Adame-Garcia SR, Li S, Chen CL, Cianfrocco MA, Gutkind JS, Cash JN, Tesmer JJG. Structural and dynamic changes in P-Rex1 upon activation by PIP 3 and inhibition by IP 4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.15.557836. [PMID: 37745379 PMCID: PMC10515948 DOI: 10.1101/2023.09.15.557836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
PIP3-dependent Rac exchanger 1 (P-Rex1) is abundantly expressed in neutrophils and plays central roles in chemotaxis and cancer metastasis by serving as a guanine-nucleotide exchange factor (GEF) for Rac. The enzyme is synergistically activated by PIP3 and the heterotrimeric Gβγ subunits, but mechanistic details remain poorly understood. While investigating the regulation of P-Rex1 by PIP3, we discovered that Ins(1,3,4,5)P4 (IP4) inhibits P-Rex1 activity and induces large decreases in backbone dynamics in diverse regions of the protein. Cryo-electron microscopy analysis of the P-Rex1·IP4 complex revealed a conformation wherein the pleckstrin homology (PH) domain occludes the active site of the Dbl homology (DH) domain. This configuration is stabilized by interactions between the first DEP domain (DEP1) and the DH domain and between the PH domain and a 4-helix bundle (4HB) subdomain that extends from the C-terminal domain of P-Rex1. Disruption of the DH-DEP1 interface in a DH/PH-DEP1 fragment enhanced activity and led to a more extended conformation in solution, whereas mutations that constrain the occluded conformation led to decreased GEF activity. Variants of full-length P-Rex1 in which the DH-DEP1 and PH-4HB interfaces were disturbed exhibited enhanced activity during chemokine-induced cell migration, confirming that the observed structure represents the autoinhibited state in living cells. Interactions with PIP3-containing liposomes led to disruption of these interfaces and increased dynamics protein-wide. Our results further suggest that inositol phosphates such as IP4 help to inhibit basal P-Rex1 activity in neutrophils, similar to their inhibitory effects on phosphatidylinositol-3-kinase.
Collapse
Affiliation(s)
- Sandeep K. Ravala
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Sendi Rafael Adame-Garcia
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, San Diego, CA 92093, USA
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Chun-Liang Chen
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Michael A. Cianfrocco
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - J. Silvio Gutkind
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, San Diego, CA 92093, USA
| | - Jennifer N. Cash
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA, 95616, USA
| | - John J. G. Tesmer
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| |
Collapse
|
2
|
Yen YC, Li Y, Chen CL, Klose T, Watts VJ, Dessauer CW, Tesmer JJG. Structure of adenylyl cyclase 5 in complex with Gβγ offers insights into ADCY5-related dyskinesia. Nat Struct Mol Biol 2024:10.1038/s41594-024-01263-0. [PMID: 38589608 DOI: 10.1038/s41594-024-01263-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 03/04/2024] [Indexed: 04/10/2024]
Abstract
The nine different membrane-anchored adenylyl cyclase isoforms (AC1-9) in mammals are stimulated by the heterotrimeric G protein, Gαs, but their response to Gβγ regulation is isoform specific. In the present study, we report cryo-electron microscope structures of ligand-free AC5 in complex with Gβγ and a dimeric form of AC5 that could be involved in its regulation. Gβγ binds to a coiled-coil domain that links the AC transmembrane region to its catalytic core as well as to a region (C1b) that is known to be a hub for isoform-specific regulation. We confirmed the Gβγ interaction with both purified proteins and cell-based assays. Gain-of-function mutations in AC5 associated with human familial dyskinesia are located at the interface of AC5 with Gβγ and show reduced conditional activation by Gβγ, emphasizing the importance of the observed interaction for motor function in humans. We propose a molecular mechanism wherein Gβγ either prevents dimerization of AC5 or allosterically modulates the coiled-coil domain, and hence the catalytic core. As our mechanistic understanding of how individual AC isoforms are uniquely regulated is limited, studies such as this may provide new avenues for isoform-specific drug development.
Collapse
Affiliation(s)
- Yu-Chen Yen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Yong Li
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Thomas Klose
- Purdue Cryo-EM Facility, Hockmeyer Hall for Structural Biology, Purdue University, West Lafayette, IN, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - John J G Tesmer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
3
|
Chen CL, Syahirah R, Ravala SK, Yen YC, Klose T, Deng Q, Tesmer JJG. Molecular basis for Gβγ-mediated activation of phosphoinositide 3-kinase γ. Nat Struct Mol Biol 2024:10.1038/s41594-024-01265-y. [PMID: 38565696 DOI: 10.1038/s41594-024-01265-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024]
Abstract
The conversion of phosphatidylinositol 4,5-bisphosphate to phosphatidylinositol 3,4,5-triphosphate by phosphoinositide 3-kinase γ (PI3Kγ) is critical for neutrophil chemotaxis and cancer metastasis. PI3Kγ is activated by Gβγ heterodimers released from G protein-coupled receptors responding to extracellular signals. Here we determined cryo-electron microscopy structures of Sus scrofa PI3Kγ-human Gβγ complexes in the presence of substrates/analogs, revealing two Gβγ binding sites: one on the p110γ helical domain and another on the p101 C-terminal domain. Comparison with PI3Kγ alone reveals conformational changes in the kinase domain upon Gβγ binding that are similar to Ras·GTP-induced changes. Assays of variants perturbing the Gβγ binding sites and interdomain contacts altered by Gβγ binding suggest that Gβγ recruits the enzyme to membranes and allosterically regulates activity via both sites. Studies of zebrafish neutrophil migration align with these findings, paving the way for in-depth investigation of Gβγ-mediated activation mechanisms in this enzyme family and drug development for PI3Kγ.
Collapse
Affiliation(s)
- Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Ramizah Syahirah
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Sandeep K Ravala
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Yu-Chen Yen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Thomas Klose
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Purdue Cryo-EM Facility, Purdue University, West Lafayette, IN, USA
| | - Qing Deng
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - John J G Tesmer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
4
|
Cervantes-Villagrana RD, García-Jiménez I, Vázquez-Prado J. Guanine nucleotide exchange factors for Rho GTPases (RhoGEFs) as oncogenic effectors and strategic therapeutic targets in metastatic cancer. Cell Signal 2023; 109:110749. [PMID: 37290677 DOI: 10.1016/j.cellsig.2023.110749] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/11/2023] [Accepted: 06/01/2023] [Indexed: 06/10/2023]
Abstract
Metastatic cancer cells dynamically adjust their shape to adhere, invade, migrate, and expand to generate secondary tumors. Inherent to these processes is the constant assembly and disassembly of cytoskeletal supramolecular structures. The subcellular places where cytoskeletal polymers are built and reorganized are defined by the activation of Rho GTPases. These molecular switches directly respond to signaling cascades integrated by Rho guanine nucleotide exchange factors (RhoGEFs), which are sophisticated multidomain proteins that control morphological behavior of cancer and stromal cells in response to cell-cell interactions, tumor-secreted factors and actions of oncogenic proteins within the tumor microenvironment. Stromal cells, including fibroblasts, immune and endothelial cells, and even projections of neuronal cells, adjust their shapes and move into growing tumoral masses, building tumor-induced structures that eventually serve as metastatic routes. Here we review the role of RhoGEFs in metastatic cancer. They are highly diverse proteins with common catalytic modules that select among a variety of homologous Rho GTPases enabling them to load GTP, acquiring an active conformation that stimulates effectors controlling actin cytoskeleton remodeling. Therefore, due to their strategic position in oncogenic signaling cascades, and their structural diversity flanking common catalytic modules, RhoGEFs possess unique characteristics that make them conceptual targets of antimetastatic precision therapies. Preclinical proof of concept, demonstrating the antimetastatic effect of inhibiting either expression or activity of βPix (ARHGEF7), P-Rex1, Vav1, ARHGEF17, and Dock1, among others, is emerging.
Collapse
|
5
|
Matsumoto S, Ishida S, Terayama K, Okuno Y. Quantitative analysis of protein dynamics using a deep learning technique combined with experimental cryo-EM density data and MD simulations. Biophys Physicobiol 2023; 20:e200022. [PMID: 38496243 PMCID: PMC10941960 DOI: 10.2142/biophysico.bppb-v20.0022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/12/2023] [Indexed: 03/19/2024] Open
Abstract
Protein functions associated with biological activity are precisely regulated by both tertiary structure and dynamic behavior. Thus, elucidating the high-resolution structures and quantitative information on in-solution dynamics is essential for understanding the molecular mechanisms. The main experimental approaches for determining tertiary structures include nuclear magnetic resonance (NMR), X-ray crystallography, and cryogenic electron microscopy (cryo-EM). Among these procedures, recent remarkable advances in the hardware and analytical techniques of cryo-EM have increasingly determined novel atomic structures of macromolecules, especially those with large molecular weights and complex assemblies. In addition to these experimental approaches, deep learning techniques, such as AlphaFold 2, accurately predict structures from amino acid sequences, accelerating structural biology research. Meanwhile, the quantitative analyses of the protein dynamics are conducted using experimental approaches, such as NMR and hydrogen-deuterium mass spectrometry, and computational approaches, such as molecular dynamics (MD) simulations. Although these procedures can quantitatively explore dynamic behavior at high resolution, the fundamental difficulties, such as signal crowding and high computational cost, greatly hinder their application to large and complex biological macromolecules. In recent years, machine learning techniques, especially deep learning techniques, have been actively applied to structural data to identify features that are difficult for humans to recognize from big data. Here, we review our approach to accurately estimate dynamic properties associated with local fluctuations from three-dimensional cryo-EM density data using a deep learning technique combined with MD simulations.
Collapse
Affiliation(s)
| | - Shoichi Ishida
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa 230-0045, Japan
| | - Kei Terayama
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa 230-0045, Japan
- RIKEN Center for Computational Science, Kobe, Hyogo 650-0047, Japan
| | - Yasuhshi Okuno
- Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
- RIKEN Center for Computational Science, Kobe, Hyogo 650-0047, Japan
| |
Collapse
|
6
|
Chen CL, Syahirah R, Ravala SK, Yen YC, Klose T, Deng Q, Tesmer JJG. Molecular basis for Gβγ-mediated activation of phosphoinositide 3-kinase γ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.04.539492. [PMID: 37205329 PMCID: PMC10187307 DOI: 10.1101/2023.05.04.539492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The conversion of PIP2 to PIP3 by phosphoinositide 3-kinase γ (PI3Kγ) is a critical step in neutrophil chemotaxis and is essential for metastasis in many types of cancer. PI3Kγ is activated via directed interaction with Gβγ heterodimers released from cell-surface G protein-coupled receptors (GPCRs) responding to extracellular signals. To resolve how Gβγ activates PI3Kγ, we determined cryo-EM reconstructions of PI3Kγ-Gβγ complexes in the presence of various substrates/analogs, revealing two distinct Gβγ binding sites, one on the p110γ helical domain and one on the C-terminal domain of the p101 subunit. Comparison of these complexes with structures of PI3Kγ alone demonstrates conformational changes in the kinase domain upon Gβγ binding similar to those induced by Ras·GTP. Assays of variants perturbing the two Gβγ binding sites and interdomain contacts that change upon Gβγ binding suggest that Gβγ not only recruits the enzyme to membranes but also allosterically controls activity via both sites. Studies in a zebrafish model examining neutrophil migration are consistent with these results. These findings set the stage for future detailed investigation of Gβγ-mediated activation mechanisms in this enzyme family and will aid in developing drugs selective for PI3Kγ.
Collapse
Affiliation(s)
- Chun-Liang Chen
- Departments of Biological Sciences & Medicinal Chemistry and Molecular Pharmacology, Purdue University. 240 S. Martin Jischke Drive, West Lafayette, IN 47907
| | - Ramizah Syahirah
- Department of Biological Sciences, Purdue University. 915 W State St, West Lafayette, IN 47907
| | - Sandeep K Ravala
- Departments of Biological Sciences & Medicinal Chemistry and Molecular Pharmacology, Purdue University. 240 S. Martin Jischke Drive, West Lafayette, IN 47907
| | - Yu-Chen Yen
- Departments of Biological Sciences & Medicinal Chemistry and Molecular Pharmacology, Purdue University. 240 S. Martin Jischke Drive, West Lafayette, IN 47907
| | - Thomas Klose
- Purdue Cryo-EM Facility, Purdue University. 240 S. Martin Jischke Drive, West Lafayette, IN 47907
| | - Qing Deng
- Department of Biological Sciences, Purdue University. 915 W State St, West Lafayette, IN 47907
- Purdue Institute for Inflammation, Immunology & Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - John J G Tesmer
- Departments of Biological Sciences & Medicinal Chemistry and Molecular Pharmacology, Purdue University. 240 S. Martin Jischke Drive, West Lafayette, IN 47907
| |
Collapse
|
7
|
Yen YC, Li Y, Chen CL, Klose T, Watts VJ, Dessauer CW, Tesmer JJG. Isoform Specific Regulation of Adenylyl Cyclase 5 by Gβγ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539090. [PMID: 37205557 PMCID: PMC10187219 DOI: 10.1101/2023.05.02.539090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The nine different membrane-anchored adenylyl cyclase isoforms (AC1-9) in mammals are stimulated by the heterotrimeric G protein Gαs, but their response to Gβγ regulation is isoform-specific. For example, AC5 is conditionally activated by Gβγ. Here, we report cryo-EM structures of ligand-free AC5 in complex with Gβγ and of a dimeric form of AC5 that could be involved in its regulation. Gβγ binds to a coiled-coil domain that links the AC transmembrane region to its catalytic core as well as to a region (C1b) that is known to be a hub for isoform-specific regulation. We confirmed the Gβγ interaction with both purified proteins and cell-based assays. The interface with Gβγ involves AC5 residues that are subject to gain-of-function mutations in humans with familial dyskinesia, indicating that the observed interaction is important for motor function. A molecular mechanism wherein Gβγ either prevents dimerization of AC5 or allosterically modulates the coiled-coil domain, and hence the catalytic core, is proposed. Because our mechanistic understanding of how individual AC isoforms are uniquely regulated is limited, studies such as this may provide new avenues for isoform-specific drug development.
Collapse
Affiliation(s)
- Yu-Chen Yen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Yong Li
- Department Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Thomas Klose
- Purdue CryoEM Facility, Suite 171, Hockmeyer Hall for Structural Biology, Purdue University, West Lafayette, IN, USA
| | - Val J Watts
- Department of Molecular Pharmacology and Medicinal Chemistry, Purdue University, West Lafayette, IN, USA
| | - Carmen W Dessauer
- Department Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - John J. G. Tesmer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Molecular Pharmacology and Medicinal Chemistry, Purdue University, West Lafayette, IN, USA
| |
Collapse
|
8
|
Burroughs A, Aravind L. New biochemistry in the Rhodanese-phosphatase superfamily: emerging roles in diverse metabolic processes, nucleic acid modifications, and biological conflicts. NAR Genom Bioinform 2023; 5:lqad029. [PMID: 36968430 PMCID: PMC10034599 DOI: 10.1093/nargab/lqad029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/10/2023] [Accepted: 03/09/2023] [Indexed: 03/25/2023] Open
Abstract
The protein-tyrosine/dual-specificity phosphatases and rhodanese domains constitute a sprawling superfamily of Rossmannoid domains that use a conserved active site with a cysteine to catalyze a range of phosphate-transfer, thiotransfer, selenotransfer and redox activities. While these enzymes have been extensively studied in the context of protein/lipid head group dephosphorylation and various thiotransfer reactions, their overall diversity and catalytic potential remain poorly understood. Using comparative genomics and sequence/structure analysis, we comprehensively investigate and develop a natural classification for this superfamily. As a result, we identified several novel clades, both those which retain the catalytic cysteine and those where a distinct active site has emerged in the same location (e.g. diphthine synthase-like methylases and RNA 2' OH ribosyl phosphate transferases). We also present evidence that the superfamily has a wider range of catalytic capabilities than previously known, including a set of parallel activities operating on various sugar/sugar alcohol groups in the context of NAD+-derivatives and RNA termini, and potential phosphate transfer activities involving sugars and nucleotides. We show that such activities are particularly expanded in the RapZ-C-DUF488-DUF4326 clade, defined here for the first time. Some enzymes from this clade are predicted to catalyze novel DNA-end processing activities as part of nucleic-acid-modifying systems that are likely to function in biological conflicts between viruses and their hosts.
Collapse
Affiliation(s)
- A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| |
Collapse
|
9
|
Abstract
GPR21 is a class-A orphan G protein-coupled receptor (GPCR) and a potential therapeutic target for type 2 diabetes and other metabolic disorders. This receptor shows high basal activity in coupling to multiple G proteins in the absence of any known endogenous agonist or synthetic ligand. Here, we present the structures of ligand-free human GPR21 bound to heterotrimeric miniGs and miniG15 proteins, respectively. We identified an agonist-like motif in extracellular loop 2 (ECL2) that occupies the orthosteric pocket and promotes receptor activation. A side pocket that may be employed as a new ligand binding site was also uncovered. Remarkably, G protein binding is accommodated by a flexible cytoplasmic portion of transmembrane helix 6 (TM6) which adopts little or undetectable outward movement. These findings will enable the design of modulators for GPR21 for understanding its signal transduction and exploring opportunity for deorphanization.
Collapse
|
10
|
Esser TK, Böhning J, Fremdling P, Bharat T, Gault J, Rauschenbach S. Cryo-EM samples of gas-phase purified protein assemblies using native electrospray ion-beam deposition. Faraday Discuss 2022; 240:67-80. [PMID: 36065984 PMCID: PMC9641999 DOI: 10.1039/d2fd00065b] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An increasing number of studies on biomolecular function indirectly combine mass spectrometry (MS) with imaging techniques such as cryo electron microscopy (cryo-EM). This approach allows information on the homogeneity, stoichiometry, shape, and interactions of native protein complexes to be obtained, complementary to high-resolution protein structures. We have recently demonstrated TEM sample preparation via native electrospray ion-beam deposition (ES-IBD) as a direct link between native MS and cryo-EM. This workflow forms a potential new route to the reliable preparation of homogeneous cryo-EM samples and a better understanding of the relation between native solution-phase and native-like gas-phase structures. However, many aspects of the workflow need to be understood and optimized to obtain performance comparable to that of state-of-the-art cryo-EM. Here, we expand on the previous discussion of key factors by probing the effects of substrate type and deposition energy. We present and discuss micrographs from native ES-IBD samples with amorphous carbon, graphene, and graphene oxide, as well as landing energies in the range between 2 and 150 eV per charge.
Collapse
Affiliation(s)
- Tim K. Esser
- Department of Chemistry, University of OxfordOxfordOX1 3TFUK
| | - Jan Böhning
- Sir William Dunn School of Pathology, University of OxfordSouth Parks RoadOxfordOX1 3REUK
| | - Paul Fremdling
- Department of Chemistry, University of OxfordOxfordOX1 3TFUK
| | - Tanmay Bharat
- Sir William Dunn School of Pathology, University of OxfordSouth Parks RoadOxfordOX1 3REUK,Structural Studies Division, MRC Laboratory of Molecular BiologyFrancis Crick AvenueCambridgeCB2 0QHUK
| | - Joseph Gault
- Department of Chemistry, University of OxfordOxfordOX1 3TFUK
| | - Stephan Rauschenbach
- Department of Chemistry, University of OxfordOxfordOX1 3TFUK,Max Planck Institute for Solid State ResearchHeisenbergstrasse 1StuttgartDE-70569Germany
| |
Collapse
|
11
|
Structure of the metastatic factor P-Rex1 reveals a two-layered autoinhibitory mechanism. Nat Struct Mol Biol 2022; 29:767-773. [PMID: 35864164 PMCID: PMC9371973 DOI: 10.1038/s41594-022-00804-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/09/2022] [Indexed: 11/08/2022]
Abstract
P-Rex (PI(3,4,5)P3-dependent Rac exchanger) guanine nucleotide exchange factors potently activate Rho GTPases. P-Rex guanine nucleotide exchange factors are autoinhibited, synergistically activated by Gβγ and PI(3,4,5)P3 binding and dysregulated in cancer. Here, we use X-ray crystallography, cryogenic electron microscopy and crosslinking mass spectrometry to determine the structural basis of human P-Rex1 autoinhibition. P-Rex1 has a bipartite structure of N- and C-terminal modules connected by a C-terminal four-helix bundle that binds the N-terminal Pleckstrin homology (PH) domain. In the N-terminal module, the Dbl homology (DH) domain catalytic surface is occluded by the compact arrangement of the DH-PH-DEP1 domains. Structural analysis reveals a remarkable conformational transition to release autoinhibition, requiring a 126° opening of the DH domain hinge helix. The off-axis position of Gβγ and PI(3,4,5)P3 binding sites further suggests a counter-rotation of the P-Rex1 halves by 90° facilitates PH domain uncoupling from the four-helix bundle, releasing the autoinhibited DH domain to drive Rho GTPase signaling. Cryo-EM, X-ray crystallography and crosslinking mass spectrometry are harnessed to solve the structure of the full-length Rho-GEF P-Rex1, uncovering a two-layered mechanism of autoinhibition released upon Gβγ and PI(3,4,5)P3 binding.
Collapse
|
12
|
Lawson CD, Hornigold K, Pan D, Niewczas I, Andrews S, Clark J, Welch HCE. Small-molecule inhibitors of P-Rex guanine-nucleotide exchange factors. Small GTPases 2022; 13:307-326. [PMID: 36342857 PMCID: PMC9645260 DOI: 10.1080/21541248.2022.2131313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
P-Rex1 and P-Rex2 are guanine-nucleotide exchange factors (GEFs) that activate Rac small GTPases in response to the stimulation of G protein-coupled receptors and phosphoinositide 3-kinase. P-Rex Rac-GEFs regulate the morphology, adhesion and migration of various cell types, as well as reactive oxygen species production and cell cycle progression. P-Rex Rac-GEFs also have pathogenic roles in the initiation, progression or metastasis of several types of cancer. With one exception, all P-Rex functions are known or assumed to be mediated through their catalytic Rac-GEF activity. Thus, inhibitors of P-Rex Rac-GEF activity would be valuable research tools. We have generated a panel of small-molecule P-Rex inhibitors that target the interface between the catalytic DH domain of P-Rex Rac-GEFs and Rac. Our best-characterized compound, P-Rex inhibitor 1 (PREX-in1), blocks the Rac-GEF activity of full-length P-Rex1 and P-Rex2, and of their isolated catalytic domains, in vitro at low-micromolar concentration, without affecting the activities of several other Rho-GEFs. PREX-in1 blocks the P-Rex1 dependent spreading of PDGF-stimulated endothelial cells and the production of reactive oxygen species in fMLP-stimulated mouse neutrophils. Structure-function analysis revealed critical structural elements of PREX-in1, allowing us to develop derivatives with increased efficacy, the best with an IC50 of 2 µM. In summary, we have developed PREX-in1 and derivative small-molecule compounds that will be useful laboratory research tools for the study of P-Rex function. These compounds may also be a good starting point for the future development of more sophisticated drug-like inhibitors aimed at targeting P-Rex Rac-GEFs in cancer.
Collapse
Affiliation(s)
- CD Lawson
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - K Hornigold
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - D Pan
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - I Niewczas
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - S Andrews
- Bioinformatics Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - J Clark
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - HCE Welch
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK,CONTACT HCE Welch Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3ATUK
| |
Collapse
|
13
|
Abstract
Cell migration, a crucial step in numerous biological processes, is tightly regulated in space and time. Cells employ Rho GTPases, primarily Rho, Rac, and Cdc42, to regulate their motility. Like other small G proteins, Rho GTPases function as biomolecular switches in regulating cell migration by operating between GDP bound 'OFF' and GTP bound 'ON' states. Guanine nucleotide exchange factors (GEFs) catalyse the shuttling of GTPases from OFF to ON state. G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors that are involved in many signalling phenomena including cell survival and cell migration events. In this review, we summarize signalling mechanisms, involving GPCRs, leading to the activation of RhoGEFs. GPCRs exhibit diverse GEF activation modes that include the interaction of heterotrimeric G protein subunits with different domains of GEFs, phosphorylation, protein-protein interaction, protein-lipid interaction, and/or a combination of these processes.
Collapse
Affiliation(s)
- Aishwarya Omble
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Kiran Kulkarni
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India,CONTACT Kiran Kulkarni Academy of Scientific and Innovative Research (Acsir), Ghaziabad 201002, India
| |
Collapse
|
14
|
D'Andrea L, Lucato CM, Marquez EA, Chang YG, Civciristov S, Mastos C, Lupton CJ, Huang C, Elmlund H, Schittenhelm RB, Mitchell CA, Whisstock JC, Halls ML, Ellisdon AM. Structural analysis of the PTEN:P-Rex2 signaling complex reveals how cancer-associated mutations coordinate to hyperactivate Rac1. Sci Signal 2021; 14:14/681/eabc4078. [PMID: 33947796 DOI: 10.1126/scisignal.abc4078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The dual-specificity phosphatase PTEN functions as a tumor suppressor by hydrolyzing PI(3,4,5)P3 to PI(4,5)P2 to inhibit PI3K-AKT signaling and cellular proliferation. P-Rex2 is a guanine nucleotide exchange factor for Rho GTPases and can be activated by Gβγ subunits downstream of G protein-coupled receptor signaling and by PI(3,4,5)P3 downstream of receptor tyrosine kinases. The PTEN:P-Rex2 complex is a commonly mutated signaling node in metastatic cancer. Assembly of the PTEN:P-Rex2 complex inhibits the activity of both proteins, and its dysregulation can drive PI3K-AKT signaling and cellular proliferation. Here, using cross-linking mass spectrometry and functional studies, we gained mechanistic insights into PTEN:P-Rex2 complex assembly and coinhibition. We found that PTEN was anchored to P-Rex2 by interactions between the PDZ-interacting motif in the PTEN C-terminal tail and the second PDZ domain of P-Rex2. This interaction bridged PTEN across the P-Rex2 surface, preventing PI(3,4,5)P3 hydrolysis. Conversely, PTEN both allosterically promoted an autoinhibited conformation of P-Rex2 and blocked its binding to Gβγ. In addition, we observed that the PTEN-deactivating mutations and P-Rex2 truncations combined to drive Rac1 activation to a greater extent than did either single variant alone. These insights enabled us to propose a class of gain-of-function, cancer-associated mutations within the PTEN:P-Rex2 interface that uncouple PTEN from the inhibition of Rac1 signaling.
Collapse
Affiliation(s)
- Laura D'Andrea
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Christina M Lucato
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Elsa A Marquez
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Yong-Gang Chang
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Srgjan Civciristov
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia
| | - Chantel Mastos
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia
| | - Christopher J Lupton
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Cheng Huang
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,Monash Proteomics & Metabolomics Facility, Monash University, Clayton, 3800 Victoria, Australia
| | - Hans Elmlund
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Ralf B Schittenhelm
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,Monash Proteomics & Metabolomics Facility, Monash University, Clayton, 3800 Victoria, Australia
| | - Christina A Mitchell
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - James C Whisstock
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, 3800 Victoria, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia.
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.
| |
Collapse
|
15
|
Baldwin PR, Lyumkis D. Tools for visualizing and analyzing Fourier space sampling in Cryo-EM. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 160:53-65. [PMID: 32645314 PMCID: PMC7785567 DOI: 10.1016/j.pbiomolbio.2020.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 12/15/2022]
Abstract
A complete understanding of how an orientation distribution contributes to a cryo-EM reconstruction remains lacking. It is necessary to begin critically assessing the set of views to gain an understanding of its effect on experimental reconstructions. Toward that end, we recently suggested that the type of orientation distribution may alter resolution measures in a systematic manner. We introduced the sampling compensation factor (SCF), which incorporates how the collection geometry might change the spectral signal-to-noise ratio (SSNR), irrespective of the other experimental aspects. We show here that knowledge of the sampling restricted to spherical surfaces of sufficiently large radii in Fourier space is equivalent to knowledge of the set of projection views. Moreover, the SCF geometrical factor may be calculated from one such surface. To aid cryo-EM practitioners, we developed a graphical user interface (GUI) tool that evaluates experimental orientation distributions. The GUI returns plots of projection directions, sampling constrained to the surface of a sphere, the SCF value, the fraction of the empty region of Fourier space, and a histogram of the sampling values over the points on a sphere. Finally, a fixed tilt angle may be incorporated to determine how tilting the grid during collection may improve the distribution of views and Fourier space sampling. We advocate this simple conception of sampling and the use of such tools as a complement to the distribution of views to capture the different aspects of the effect of projection directions on cryo-EM reconstructions.
Collapse
Affiliation(s)
- Philip R Baldwin
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA; Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 N Torrey Pines Road, La Jolla, CA, 92037, USA.
| |
Collapse
|
16
|
|
17
|
Cervantes-Villagrana RD, Beltrán-Navarro YM, García-Jiménez I, Adame-García SR, Olguín-Olguín A, Reyes-Cruz G, Vázquez-Prado J. Gβγ recruits and activates P-Rex1 via two independent binding interfaces. Biochem Biophys Res Commun 2021; 539:20-27. [PMID: 33412417 DOI: 10.1016/j.bbrc.2020.12.089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/26/2020] [Indexed: 12/19/2022]
Abstract
Gβγ marks the inner side of the plasma membrane where chemotactic GPCRs activate Rac to lead the assembly of actin filaments that push the cell to move forward. Upon dissociation from heterotrimeric Gi, Gβγ recruits and activates P-Rex1, a Rac guanine nucleotide exchange factor (RacGEF). This cytosolic chemotactic effector is kept inactive by intramolecular interactions. The mechanism by which Gβγ stimulates P-Rex1 has been debated. We hypothesized that Gβγ activates P-Rex1 by a two-step mechanism based on independent interaction interfaces to recruit and unroll this RacGEF. Using pulldown assays, we found that Gβγ binds P-Rex1-DH/PH as well as PDZ-PDZ domains. These domains and the DEP-DEP tandem interact among them and dissociate upon binding with Gβγ, arguing for a stimulatory allosteric effect. In addition, P-Rex1 catalytic activity is inhibited by its C-terminal domain. To discern P-Rex1 recruitment from activation, we studied Q-Rhox, a synthetic RhoGEF having the PDZ-RhoGEF catalytic DH/PH module, insensitive to Gβγ, swapped into P-Rex1. Gβγ recruited Q-Rhox to the plasma membrane, indicating that Gβγ/PDZ-PDZ interaction interface plays a role on P-Rex1 recruitment. In conclusion, we reconcile previous findings and propose a mechanistic model of P-Rex1 activation; accordingly, Gβγ recruits P-Rex1 via the Gβγ/PDZ-PDZ interface followed by a second contact involving the Gβγ/DH/PH interface to unleash P-Rex1 RacGEF activity at the plasma membrane.
Collapse
|
18
|
Seychell BC, Beck T. Molecular basis for protein-protein interactions. Beilstein J Org Chem 2021; 17:1-10. [PMID: 33488826 PMCID: PMC7801801 DOI: 10.3762/bjoc.17.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/07/2020] [Indexed: 01/11/2023] Open
Abstract
This minireview provides an overview on the current knowledge of protein-protein interactions, common characterisation methods to characterise them, and their role in protein complex formation with some examples. A deep understanding of protein-protein interactions and their molecular interactions is important for a number of applications, including drug design. Protein-protein interactions and their discovery are thus an interesting avenue for understanding how protein complexes, which make up the majority of proteins, work.
Collapse
Affiliation(s)
- Brandon Charles Seychell
- Universität Hamburg, Department of Chemistry, Institute of Physical Chemistry, Grindelallee 117, 20146 Hamburg, Germany
| | - Tobias Beck
- Universität Hamburg, Department of Chemistry, Institute of Physical Chemistry, Grindelallee 117, 20146 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
| |
Collapse
|
19
|
Ravala SK, Hopkins JB, Plescia CB, Allgood SR, Kane MA, Cash JN, Stahelin RV, Tesmer JJG. The first DEP domain of the RhoGEF P-Rex1 autoinhibits activity and contributes to membrane binding. J Biol Chem 2020; 295:12635-12647. [PMID: 32661198 DOI: 10.1074/jbc.ra120.014534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/08/2020] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol (3,4,5)-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1) catalyzes the exchange of GDP for GTP on Rac GTPases, thereby triggering changes in the actin cytoskeleton and in transcription. Its overexpression is highly correlated with the metastasis of certain cancers. P-Rex1 recruitment to the plasma membrane and its activity are regulated via interactions with heterotrimeric Gβγ subunits, PIP3, and protein kinase A (PKA). Deletion analysis has further shown that domains C-terminal to its catalytic Dbl homology (DH) domain confer autoinhibition. Among these, the first dishevelled, Egl-10, and pleckstrin domain (DEP1) remains to be structurally characterized. DEP1 also harbors the primary PKA phosphorylation site, suggesting that an improved understanding of this region could substantially increase our knowledge of P-Rex1 signaling and open the door to new selective chemotherapeutics. Here we show that the DEP1 domain alone can autoinhibit activity in context of the DH/PH-DEP1 fragment of P-Rex1 and interacts with the DH/PH domains in solution. The 3.1 Å crystal structure of DEP1 features a domain swap, similar to that observed previously in the Dvl2 DEP domain, involving an exposed basic loop that contains the PKA site. Using purified proteins, we show that although DEP1 phosphorylation has no effect on the activity or solution conformation of the DH/PH-DEP1 fragment, it inhibits binding of the DEP1 domain to liposomes containing phosphatidic acid. Thus, we propose that PKA phosphorylation of the DEP1 domain hampers P-Rex1 binding to negatively charged membranes in cells, freeing the DEP1 domain to associate with and inhibit the DH/PH module.
Collapse
Affiliation(s)
- Sandeep K Ravala
- Departments of Biological Sciences, Purdue University, West Lafayette, Indiana, USA.,The Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Jesse B Hopkins
- Biophysics Collaborative Access Team, Illinois Institute of Technology, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, USA
| | - Caroline B Plescia
- The Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Samantha R Allgood
- Departments of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Madison A Kane
- College of Engineering, California State University, Long Beach, California, USA
| | - Jennifer N Cash
- Department of Biological Chemistry & Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert V Stahelin
- The Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - John J G Tesmer
- Departments of Biological Sciences, Purdue University, West Lafayette, Indiana, USA .,The Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| |
Collapse
|
20
|
Li Y, Cash JN, Tesmer JJG, Cianfrocco MA. High-Throughput Cryo-EM Enabled by User-Free Preprocessing Routines. Structure 2020; 28:858-869.e3. [PMID: 32294468 PMCID: PMC7347462 DOI: 10.1016/j.str.2020.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/02/2020] [Accepted: 03/17/2020] [Indexed: 12/18/2022]
Abstract
Single-particle cryoelectron microscopy (cryo-EM) continues to grow into a mainstream structural biology technique. Recent developments in data collection strategies alongside new sample preparation devices herald a future where users will collect multiple datasets per microscope session. To make cryo-EM data processing more automatic and user-friendly, we have developed an automatic pipeline for cryo-EM data preprocessing and assessment using a combination of deep-learning and image-analysis tools. We have verified the performance of this pipeline on a number of datasets and extended its scope to include sample screening by the user-free assessment of the qualities of a series of datasets under different conditions. We propose that our workflow provides a decision-free solution for cryo-EM, making data preprocessing more generalized and robust in the high-throughput era as well as more convenient for users from a range of backgrounds.
Collapse
Affiliation(s)
- Yilai Li
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Jennifer N Cash
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - John J G Tesmer
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Michael A Cianfrocco
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|
21
|
Engen JR, Komives EA. Complementarity of Hydrogen/Deuterium Exchange Mass Spectrometry and Cryo-Electron Microscopy. Trends Biochem Sci 2020; 45:906-918. [PMID: 32487353 DOI: 10.1016/j.tibs.2020.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/23/2020] [Accepted: 05/08/2020] [Indexed: 12/18/2022]
Abstract
Methodological improvements in both single particle cryo-electron microscopy (cryo-EM) and hydrogen/deuterium exchange mass spectrometry (HDX-MS) mean that the two methods are being more frequently used together to tackle complex problems in structural biology. There are many benefits to this combination, including for the analysis of low-resolution density, for structural validation, in the analysis of individual proteins versus the same proteins in large complexes, studies of allostery, protein quality control during cryo-EM construct optimization, and in the study of protein movements/dynamics during function. As will be highlighted in this review, through careful considerations of potential sample and conformational heterogeneity, many joint studies have recently been demonstrated, and many future studies using this combination are anticipated.
Collapse
Affiliation(s)
- John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
22
|
Cianfrocco MA, Kellogg EH. What Could Go Wrong? A Practical Guide to Single-Particle Cryo-EM: From Biochemistry to Atomic Models. J Chem Inf Model 2020; 60:2458-2469. [PMID: 32078321 DOI: 10.1021/acs.jcim.9b01178] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cryo-electron microscopy (cryo-EM) has enjoyed explosive recent growth due to revolutionary advances in hardware and software, resulting in a steady stream of long-awaited, high-resolution structures with unprecedented atomic detail. With this comes an increased number of microscopes, cryo-EM facilities, and scientists eager to leverage the ability to determine protein structures without crystallization. However, numerous pitfalls and considerations beset the path toward high-resolution structures and are not necessarily obvious from literature surveys. Here, we detail the most common misconceptions when initiating a cryo-EM project and common technical hurdles, as well as their solutions, and we conclude with a vision for the future of this exciting field.
Collapse
Affiliation(s)
- Michael A Cianfrocco
- Life Sciences Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Elizabeth H Kellogg
- Department of Molecular Biology and Genetics,Cornell University, Ithaca, New York 14850, United States
| |
Collapse
|
23
|
The Rho guanine nucleotide exchange factor P-Rex1 as a potential drug target for cancer metastasis and inflammatory diseases. Pharmacol Res 2020; 153:104676. [PMID: 32006571 DOI: 10.1016/j.phrs.2020.104676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/12/2020] [Accepted: 01/27/2020] [Indexed: 12/13/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1) is a guanine nucleotide exchange factor (GEF) for Rac small GTPases and the Rac-related GTPase RhoG. P-Rex1 plays an important role in cell migration and relays intracellular signals generated through activation of G protein-coupled receptors and receptor tyrosine kinases. Studies of mouse models have found that P-Rex1 expression and activation is associated with tumor cell migration, brain development and pathological changes such as lung edema. Since its initial discovery, P-Rex1 has been known for its large size and multiple activation mechanisms that involve not only PIP3 but also the βγ subunits of heterotrimeric G proteins and a regulatory subunit of cyclic AMP-dependent kinase, PKA RIα. At the core of the GEF activity is the tandem Dbl homology domain and the pleckstrin homology domain (DH/PH domains) that are masked until activation signals unwind the P-Rex1 structure. Understanding the activation mechanisms will help designing therapeutics that target P-Rex1 for cancer and other diseases.
Collapse
|