1
|
Gewering T, Waghray D, Parey K, Jung H, Tran NNB, Zapata J, Zhao P, Chen H, Januliene D, Hummer G, Urbatsch I, Moeller A, Zhang Q. Tracing the substrate translocation mechanism in P-glycoprotein. eLife 2024; 12:RP90174. [PMID: 38259172 PMCID: PMC10945689 DOI: 10.7554/elife.90174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024] Open
Abstract
P-glycoprotein (Pgp) is a prototypical ATP-binding cassette (ABC) transporter of great biological and clinical significance.Pgp confers cancer multidrug resistance and mediates the bioavailability and pharmacokinetics of many drugs (Juliano and Ling, 1976; Ueda et al., 1986; Sharom, 2011). Decades of structural and biochemical studies have provided insights into how Pgp binds diverse compounds (Loo and Clarke, 2000; Loo et al., 2009; Aller et al., 2009; Alam et al., 2019; Nosol et al., 2020; Chufan et al., 2015), but how they are translocated through the membrane has remained elusive. Here, we covalently attached a cyclic substrate to discrete sites of Pgp and determined multiple complex structures in inward- and outward-facing states by cryoEM. In conjunction with molecular dynamics simulations, our structures trace the substrate passage across the membrane and identify conformational changes in transmembrane helix 1 (TM1) as regulators of substrate transport. In mid-transport conformations, TM1 breaks at glycine 72. Mutation of this residue significantly impairs drug transport of Pgp in vivo, corroborating the importance of its regulatory role. Importantly, our data suggest that the cyclic substrate can exit Pgp without the requirement of a wide-open outward-facing conformation, diverting from the common efflux model for Pgp and other ABC exporters. The substrate transport mechanism of Pgp revealed here pinpoints critical targets for future drug discovery studies of this medically relevant system.
Collapse
Affiliation(s)
- Theresa Gewering
- Osnabrück University, Department of Biology/Chemistry, Structural Biology SectionOsnabrückGermany
- Department of Structural Biology, Max Planck Institute of BiophysicsFrankfurtGermany
| | - Deepali Waghray
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Kristian Parey
- Osnabrück University, Department of Biology/Chemistry, Structural Biology SectionOsnabrückGermany
- Department of Structural Biology, Max Planck Institute of BiophysicsFrankfurtGermany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs)OsnabrückGermany
| | - Hendrik Jung
- Department of Theoretical Biophysics, Max Planck Institute of BiophysicsFrankfurtGermany
| | - Nghi NB Tran
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbockUnited States
| | - Joel Zapata
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbockUnited States
| | - Pengyi Zhao
- Department of Chemistry & Environmental Science, New Jersey Institute of TechnologyNewarkUnited States
| | - Hao Chen
- Department of Chemistry & Environmental Science, New Jersey Institute of TechnologyNewarkUnited States
| | - Dovile Januliene
- Osnabrück University, Department of Biology/Chemistry, Structural Biology SectionOsnabrückGermany
- Department of Structural Biology, Max Planck Institute of BiophysicsFrankfurtGermany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs)OsnabrückGermany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of BiophysicsFrankfurtGermany
- Institute for Biophysics, Goethe University FrankfurtFrankfurtGermany
| | - Ina Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbockUnited States
| | - Arne Moeller
- Osnabrück University, Department of Biology/Chemistry, Structural Biology SectionOsnabrückGermany
- Department of Structural Biology, Max Planck Institute of BiophysicsFrankfurtGermany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs)OsnabrückGermany
| | - Qinghai Zhang
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| |
Collapse
|
2
|
Kaur G, Helmer RA, Martinez-Marin D, Sennoune SR, Washburn RL, Martinez-Zaguilan R, Dufour JM, Chilton BS. Helicase-like transcription factor (Hltf)-deletion activates Hmgb1-Rage axis and granzyme A-mediated killing of pancreatic β cells resulting in neonatal lethality. PLoS One 2023; 18:e0286109. [PMID: 37624843 PMCID: PMC10456192 DOI: 10.1371/journal.pone.0286109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 05/09/2023] [Indexed: 08/27/2023] Open
Abstract
Epigenetic mechanisms are integral to pancreatic β cell function. Promoter hypermethylation of the helicase like-transcription factor (HLTF) gene-a component of the cellular DNA damage response that contributes to genome stability-has been implicated in age-associated changes in β cells. To study HLTF, we generated global and β cell-specific (β) Hltf knockout (KO) immune competent (IC) and immune deficient (ID) Rag2-/IL2- mice. IC global and β Hltf KO mice were neonatal lethal whereas ID global and β Hltf KO newborn mice had normal survival. This focused our investigation on the effects of Rag2 interruption with common gamma chain interruption on β cell function/survival. Three-way transcriptomic (RNAseq) analyses of whole pancreata from IC and ID newborn β Hltf KO and wild type (Hltf +/+) controls combined with spatially resolved transcriptomic analysis of formalin fixed paraffin embedded tissue, immunohistochemistry and laser scanning confocal microscopy showed DNA damage caused by β Hltf KO in IC mice upregulated the Hmgb1-Rage axis and a gene signature for innate immune cells. Perforin-delivered granzyme A (GzmA) activation of DNase, Nme1, showed damaged nuclear single-stranded DNA (γH2AX immunostaining). This caspase-independent method of cell death was supported by transcriptional downregulation of Serpinc1 gene that encodes a serine protease inhibitor of GzmA. Increased transcriptional availability of complement receptors C3ar1 and C5ar1 likely invited crosstalk with Hmgb1 to amplify inflammation. This study explores the complex dialog between β cells and immune cells during development. It has implications for the initiation of type I diabetes in utero when altered gene expression that compromises genome stability invokes a localized inflammatory response.
Collapse
Affiliation(s)
- Gurvinder Kaur
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Rebecca A. Helmer
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Dalia Martinez-Marin
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
- Department of Immunology and Molecular Microbiology, Texas Tech University-Health Sciences Center, Lubbock, Texas, United States of America
| | - Souad R. Sennoune
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Rachel L. Washburn
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Raul Martinez-Zaguilan
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jannette M. Dufour
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Beverly S. Chilton
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| |
Collapse
|
3
|
Holcomb MC, Gao GJJ, Servati M, Schneider D, McNeely PK, Thomas JH, Blawzdziewicz J. Mechanical feedback and robustness of apical constrictions in Drosophila embryo ventral furrow formation. PLoS Comput Biol 2021; 17:e1009173. [PMID: 34228708 PMCID: PMC8284804 DOI: 10.1371/journal.pcbi.1009173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 07/16/2021] [Accepted: 06/10/2021] [Indexed: 11/19/2022] Open
Abstract
Formation of the ventral furrow in the Drosophila embryo relies on the apical constriction of cells in the ventral region to produce bending forces that drive tissue invagination. In our recent paper we observed that apical constrictions during the initial phase of ventral furrow formation produce elongated patterns of cellular constriction chains prior to invagination and argued that these are indicative of tensile stress feedback. Here, we quantitatively analyze the constriction patterns preceding ventral furrow formation and find that they are consistent with the predictions of our active-granular-fluid model of a monolayer of mechanically coupled stress-sensitive constricting particles. Our model shows that tensile feedback causes constriction chains to develop along underlying precursor tensile stress chains that gradually strengthen with subsequent cellular constrictions. As seen in both our model and available optogenetic experiments, this mechanism allows constriction chains to penetrate or circumvent zones of reduced cell contractility, thus increasing the robustness of ventral furrow formation to spatial variation of cell contractility by rescuing cellular constrictions in the disrupted regions.
Collapse
Affiliation(s)
- Michael C. Holcomb
- Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas, United States of America
| | - Guo-Jie Jason Gao
- Department of Mathematical and Systems Engineering, Shizuoka University, Hamamatsu, Japan
| | - Mahsa Servati
- Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas, United States of America
| | - Dylan Schneider
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, United States of America
| | - Presley K. McNeely
- Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas, United States of America
| | - Jeffrey H. Thomas
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jerzy Blawzdziewicz
- Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas, United States of America
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, United States of America
| |
Collapse
|
4
|
Kaur G, Helmer RA, Smith LA, Martinez-Zaguilan R, Dufour JM, Chilton BS. Alternative splicing of helicase-like transcription factor (Hltf): Intron retention-dependent activation of immune tolerance at the feto-maternal interface. PLoS One 2018; 13:e0200211. [PMID: 29975766 PMCID: PMC6033450 DOI: 10.1371/journal.pone.0200211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/21/2018] [Indexed: 12/21/2022] Open
Abstract
Hltf is regulated by intron retention, and global Hltf-deletion causes perinatal lethality from hypoglycemia. In heart, full-length Hltf is a transcriptional regulator of Hif-1α that controls transport systems. Thus, we tested the hypothesis that Hltf deletion from placenta caused or exacerbated neonatal hypoglycemia via Hif-1α regulation of nutrient transporters. RNA-seq data analyses identified significant changes in transcript expression and alternative splicing (AS) in E18.5 placentome. iPathwayGuide was used for gene ontology (GO) analysis of biological processes, molecular functions and cellular components. Elim pruning algorithm identified hierarchical relationships. The methylome was interrogated by Methyl-MiniSeq Epiquest analysis. GO analysis identified gene enrichment within biological processes. Protein expression was visualized with immunohistochemistry. Although two Hltf mRNA isoforms are quantifiable in most murine tissues, only the truncated Hltf isoform is expressed in placenta. The responsible intron retention event occurs in the absence of DNA methylation. iPathwayGuide analysis identified 157 target genes of 11,538 total genes with measured expression. These were obtained using a threshold of 0.05 for statistical significance (p-value) and a long fold change of expression with absolute value of at least 0.6. Hltf deletion altered transcription of trophoblast lineage-specific genes, and increased transcription of the Cxcr7 (p = 0.004) gene whose protein product is a co-receptor for human and simian immunodeficiency viruses. Concomitant increased Cxcr7 protein was identified with immunolabeling. Hltf deletion had no effect on transcription or site-specific methylation patterns of Hif-1α, the major glucose transporters, or System A amino acid transporters. There was no measureable evidence of uteroplacental dysfunction or fetal compromise. iPathGuide analysis revealed Hltf suppresses cytolysis (10/21 genes; p-value 1.900e-12; p-value correction: Elim pruning; GO:019835) including the perforin-granzyme pathway in uterine natural killer cells. Our findings 1) prove the truncated Hltf protein isoform is a transcription factor, 2) establish a functional link between AS of Hltf and immunosuppression at the feto-maternal interface, 3) correlate intron retention with the absence of DNA methylation, and 4) underscore the importance of differential splicing analysis to identify Hltf's functional diversity.
Collapse
Affiliation(s)
- Gurvinder Kaur
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Rebecca A. Helmer
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Lisa A. Smith
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Raul Martinez-Zaguilan
- Department of Cell Physiology & Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jannette M. Dufour
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Beverly S. Chilton
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| |
Collapse
|