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Norris AC, Mansueto AJ, Jimenez M, Yazlovitskaya EM, Jain BK, Graham TR. Flipping the script: Advances in understanding how and why P4-ATPases flip lipid across membranes. Biochim Biophys Acta Mol Cell Res 2024; 1871:119700. [PMID: 38382846 DOI: 10.1016/j.bbamcr.2024.119700] [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] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 11/15/2023] [Accepted: 02/16/2024] [Indexed: 02/23/2024]
Abstract
Type IV P-type ATPases (P4-ATPases) are a family of transmembrane enzymes that translocate lipid substrates from the outer to the inner leaflet of biological membranes and thus create an asymmetrical distribution of lipids within membranes. On the cellular level, this asymmetry is essential for maintaining the integrity and functionality of biological membranes, creating platforms for signaling events and facilitating vesicular trafficking. On the organismal level, this asymmetry has been shown to be important in maintaining blood homeostasis, liver metabolism, neural development, and the immune response. Indeed, dysregulation of P4-ATPases has been linked to several diseases; including anemia, cholestasis, neurological disease, and several cancers. This review will discuss the evolutionary transition of P4-ATPases from cation pumps to lipid flippases, the new lipid substrates that have been discovered, the significant advances that have been achieved in recent years regarding the structural mechanisms underlying the recognition and flipping of specific lipids across biological membranes, and the consequences of P4-ATPase dysfunction on cellular and physiological functions. Additionally, we emphasize the requirement for additional research to comprehensively understand the involvement of flippases in cellular physiology and disease and to explore their potential as targets for therapeutics in treating a variety of illnesses. The discussion in this review will primarily focus on the budding yeast, C. elegans, and mammalian P4-ATPases.
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Affiliation(s)
- Adriana C Norris
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Mariana Jimenez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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2
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Duan HD, Jain BK, Li H, Graham TR, Li H. Structural insight into an Arl1-ArfGEF complex involved in Golgi recruitment of a GRIP-domain golgin. Nat Commun 2024; 15:1942. [PMID: 38431634 PMCID: PMC10908827 DOI: 10.1038/s41467-024-46304-w] [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] [Received: 08/10/2023] [Accepted: 02/20/2024] [Indexed: 03/05/2024] Open
Abstract
Arl1 is an Arf-like (Arl) GTP-binding protein that interacts with the guanine nucleotide exchange factor Gea2 to recruit the golgin Imh1 to the Golgi. The Arl1-Gea2 complex also binds and activates the phosphatidylserine flippase Drs2 and these functions may be related, although the underlying molecular mechanism is unclear. Here we report high-resolution cryo-EM structures of the full-length Gea2 and the Arl1-Gea2 complex. Gea2 is a large protein with 1459 residues and is composed of six domains (DCB, HUS, SEC7, HDS1-3). We show that Gea2 assembles a stable dimer via an extensive interface involving hydrophobic and electrostatic interactions in the DCB and HUS region. Contrary to the previous report on a Gea2 homolog in which Arl1 binds to the dimerization surface of the DCB domain, implying a disrupted dimer upon Arl1 binding, we find that Arl1 binds to the outside surface of the Gea2 DCB domain, leaving the Gea2 dimer intact. The interaction between Arl1 and Gea2 involves the classic FWY aromatic residue triad as well as two Arl1-specific residues. We show that key mutations that disrupt the Arl1-Gea2 interaction abrogate Imh1 Golgi association. This work clarifies the Arl1-Gea2 interaction and improves our understanding of molecular events in the membrane trafficking.
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Affiliation(s)
- H Diessel Duan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Hua Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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Norris AC, Yazlovitskaya EM, Yang TS, Mansueto A, Stafford JM, Graham TR. ATP10A deficiency results in male-specific infertility in mice. Front Cell Dev Biol 2024; 12:1310593. [PMID: 38415274 PMCID: PMC10896839 DOI: 10.3389/fcell.2024.1310593] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/29/2024] [Indexed: 02/29/2024] Open
Abstract
Over 8% of couples worldwide are affected by infertility and nearly half of these cases are due to male-specific issues where the underlying cause is often unknown. Therefore, discovery of new genetic factors contributing to male-specific infertility in model organisms can enhance our understanding of the etiology of this disorder. Here we show that murine ATP10A, a phospholipid flippase, is highly expressed in male reproductive organs, specifically the testes and vas deferens. Therefore, we tested the influence of ATP10A on reproduction by examining fertility of Atp10A knockout mice. Our findings reveal that Atp10A deficiency leads to male-specific infertility, but does not perturb fertility in the females. The Atp10A deficient male mice exhibit smaller testes, reduced sperm count (oligozoospermia) and lower sperm motility (asthenozoospermia). Additionally, Atp10A deficient mice display testes and vas deferens histopathological abnormalities, as well as altered total and relative amounts of hormones associated with the hypothalamic-pituitary-gonadal axis. Surprisingly, circulating testosterone is elevated 2-fold in the Atp10A knockout mice while luteinizing hormone, follicle stimulating hormone, and inhibin B levels were not significantly different from WT littermates. The knockout mice also exhibit elevated levels of gonadotropin receptors and alterations to ERK, p38 MAPK, Akt, and cPLA2-dependent signaling in the testes. Atp10A was knocked out in the C57BL/6J background, which also carries an inactivating nonsense mutation in the closely related lipid flippase, Atp10D. We have corrected the Atp10D nonsense mutation using CRISPR/Cas9 and determined that loss of Atp10A alone is sufficient to cause infertility in male mice. Collectively, these findings highlight the critical role of ATP10A in male fertility in mice and provide valuable insights into the underlying molecular mechanisms.
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Affiliation(s)
- Adriana C Norris
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | | | - Tzushan Sharon Yang
- Division of Comparative Medicine, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Alex Mansueto
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - John M Stafford
- Tennessee Valley Healthcare System, Nashville, TN, United States
- Division of Endocrinology, Diabetes and Metabolism, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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Norris AC, Yazlovitskaya EM, Zhu L, Rose BS, May JC, Gibson-Corley KN, McLean JA, Stafford JM, Graham TR. Deficiency of the lipid flippase ATP10A causes diet-induced dyslipidemia in female mice. Sci Rep 2024; 14:343. [PMID: 38172157 PMCID: PMC10764864 DOI: 10.1038/s41598-023-50360-5] [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] [Received: 08/11/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Genetic association studies have linked ATP10A and closely related type IV P-type ATPases (P4-ATPases) to insulin resistance and vascular complications, such as atherosclerosis. ATP10A translocates phosphatidylcholine and glucosylceramide across cell membranes, and these lipids or their metabolites play important roles in signal transduction pathways regulating metabolism. However, the influence of ATP10A on lipid metabolism in mice has not been explored. Here, we generated gene-specific Atp10A knockout mice and show that Atp10A-/- mice fed a high-fat diet did not gain excess weight relative to wild-type littermates. However, Atp10A-/- mice displayed female-specific dyslipidemia characterized by elevated plasma triglycerides, free fatty acids and cholesterol, as well as altered VLDL and HDL properties. We also observed increased circulating levels of several sphingolipid species along with reduced levels of eicosanoids and bile acids. The Atp10A-/- mice also displayed hepatic insulin resistance without perturbations to whole-body glucose homeostasis. Thus, ATP10A has a sex-specific role in regulating plasma lipid composition and maintaining hepatic liver insulin sensitivity in mice.
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Affiliation(s)
- Adriana C Norris
- Department of Biological Sciences, Vanderbilt University, 465 21St Ave S, Nashville, TN, 37212, USA
| | - Eugenia M Yazlovitskaya
- Department of Biological Sciences, Vanderbilt University, 465 21St Ave S, Nashville, TN, 37212, USA
| | - Lin Zhu
- Division of Endocrinology, Diabetes and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bailey S Rose
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, USA
| | - Jody C May
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, USA
| | - Katherine N Gibson-Corley
- Division of Comparative Medicine, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John A McLean
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, USA
| | - John M Stafford
- Division of Endocrinology, Diabetes and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
- Tennessee Valley Healthcare System, Veterans Affairs, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, 465 21St Ave S, Nashville, TN, 37212, USA.
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Yazlovitskaya EM, Graham TR. Type IV P-Type ATPases: Recent Updates in Cancer Development, Progression, and Treatment. Cancers (Basel) 2023; 15:4327. [PMID: 37686603 PMCID: PMC10486736 DOI: 10.3390/cancers15174327] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/15/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
Adaptations of cancer cells for survival are remarkable. One of the most significant properties of cancer cells to prevent the immune system response and resist chemotherapy is the altered lipid metabolism and resulting irregular cell membrane composition. The phospholipid distribution in the plasma membrane of normal animal cells is distinctly asymmetric. Lipid flippases are a family of enzymes regulating membrane asymmetry, and the main class of flippases are type IV P-type ATPases (P4-ATPases). Alteration in the function of flippases results in changes to membrane organization. For some lipids, such as phosphatidylserine, the changes are so drastic that they are considered cancer biomarkers. This review will analyze and discuss recent publications highlighting the role that P4-ATPases play in the development and progression of various cancer types, as well as prospects of targeting P4-ATPases for anti-cancer treatment.
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Affiliation(s)
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
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6
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Norris AC, Yazlovitskaya EM, Zhu L, Rose BS, May JC, Gibson-Corley KN, McLean JA, Stafford JM, Graham TR. Deficiency of the lipid flippase ATP10A causes diet-induced dyslipidemia in female mice. bioRxiv 2023:2023.06.16.545392. [PMID: 37398141 PMCID: PMC10312798 DOI: 10.1101/2023.06.16.545392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Genetic association studies have linked ATP10A and closely related type IV P-type ATPases (P4-ATPases) to insulin resistance and vascular complications, such as atherosclerosis. ATP10A translocates phosphatidylcholine and glucosylceramide across cell membranes, and these lipids or their metabolites play important roles in signal transduction pathways regulating metabolism. However, the influence of ATP10A on lipid metabolism in mice has not been explored. Here, we generated gene-specific Atp10A knockout mice and show that Atp10A-/- mice fed a high-fat diet did not gain excess weight relative to wild-type littermates. However, Atp10A-/- mice displayed female-specific dyslipidemia characterized by elevated plasma triglycerides, free fatty acids and cholesterol, as well as altered VLDL and HDL properties. We also observed increased circulating levels of several sphingolipid species along with reduced levels of eicosanoids and bile acids. The Atp10A-/- mice also displayed hepatic insulin resistance without perturbations to whole-body glucose homeostasis. Thus, ATP10A has a sex-specific role in regulating plasma lipid composition and maintaining hepatic liver insulin sensitivity in mice.
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Affiliation(s)
- Adriana C. Norris
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Lin Zhu
- Division of Endocrinology, Diabetes and Metabolism, Vanderbilt University Medical Center, USA
| | - Bailey S. Rose
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee, USA
| | - Jody C. May
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee, USA
| | - Katherine N. Gibson-Corley
- Division of Comparative Medicine, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John A. McLean
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee, USA
| | - John M. Stafford
- Division of Endocrinology, Diabetes and Metabolism, Vanderbilt University Medical Center, USA
- Tennessee Valley Healthcare System, Veterans Affairs, Nashville, Tennessee, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Tennessee, USA
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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Pazos I, Puig‐Tintó M, Betancur L, Cordero J, Jiménez‐Menéndez N, Abella M, Hernández AC, Duran AG, Adachi‐Fernández E, Belmonte‐Mateos C, Sabido‐Bozo S, Tosi S, Nezu A, Oliva B, Colombelli J, Graham TR, Yoshimori T, Muñiz M, Hamasaki M, Gallego O. The P4-ATPase Drs2 interacts with and stabilizes the multisubunit tethering complex TRAPPIII in yeast. EMBO Rep 2023; 24:e56134. [PMID: 36929574 PMCID: PMC10157312 DOI: 10.15252/embr.202256134] [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] [Received: 09/16/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 03/17/2023] Open
Abstract
Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are partially understood. Here, we systematically investigate the interactome that regulates MTCs. We report that P4-ATPases, a family of lipid flippases, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We use the P4-ATPase Drs2 as a paradigm to investigate the mechanism and biological relevance of this interplay during transport of Atg9 vesicles. Binding of Trs85, the sole-specific subunit of TRAPPIII, to the N-terminal tail of Drs2 stabilizes TRAPPIII on membranes loaded with Atg9 and is required for Atg9 delivery during selective autophagy, a role that is independent of P4-ATPase canonical functions. This mechanism requires a conserved I(S/R)TTK motif that also mediates the interaction of the P4-ATPases Dnf1 and Dnf2 with MTCs, suggesting a broader role of P4-ATPases in MTC regulation.
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Affiliation(s)
- Irene Pazos
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Marta Puig‐Tintó
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Laura Betancur
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Jorge Cordero
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | | | - Marc Abella
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Altair C Hernández
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Ana G Duran
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Emi Adachi‐Fernández
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Carla Belmonte‐Mateos
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Susana Sabido‐Bozo
- Department of Cell BiologyUniversity of SevilleSevilleSpain
- Instituto de Biomedicina de Sevilla (IBiS)Hospital Universitario Virgen del Rocío/CSIC/Universidad de SevillaSevilleSpain
| | - Sébastien Tosi
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
| | - Akiko Nezu
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Baldomero Oliva
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
- Structural Bioinformatics Lab (GRIB‐IMIM)BarcelonaSpain
| | - Julien Colombelli
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
| | - Todd R Graham
- Department of Biological SciencesVanderbilt UniversityNashvilleTNUSA
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Manuel Muñiz
- Department of Cell BiologyUniversity of SevilleSevilleSpain
- Instituto de Biomedicina de Sevilla (IBiS)Hospital Universitario Virgen del Rocío/CSIC/Universidad de SevillaSevilleSpain
| | - Maho Hamasaki
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Oriol Gallego
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
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Xie B, Guillem C, Date SS, Cohen CI, Jung C, Kendall AK, Best JT, Graham TR, Jackson LP. An interaction between β'-COP and the ArfGAP, Glo3, maintains post-Golgi cargo recycling. J Cell Biol 2023; 222:e202008061. [PMID: 36811888 PMCID: PMC9960064 DOI: 10.1083/jcb.202008061] [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: 08/24/2020] [Revised: 07/14/2022] [Accepted: 01/24/2023] [Indexed: 02/24/2023] Open
Abstract
The essential COPI coat mediates retrieval of transmembrane proteins at the Golgi and endosomes following recruitment by the small GTPase, Arf1. ArfGAP proteins regulate COPI coats, but molecular details for COPI recognition by ArfGAPs remain elusive. Biochemical and biophysical data reveal how β'-COP propeller domains directly engage the yeast ArfGAP, Glo3, with a low micromolar binding affinity. Calorimetry data demonstrate that both β'-COP propeller domains are required to bind Glo3. An acidic patch on β'-COP (D437/D450) interacts with Glo3 lysine residues located within the BoCCS (binding of coatomer, cargo, and SNAREs) region. Targeted point mutations in either Glo3 BoCCS or β'-COP abrogate the interaction in vitro, and loss of the β'-COP/Glo3 interaction drives Ste2 missorting to the vacuole and aberrant Golgi morphology in budding yeast. These data suggest that cells require the β'-COP/Glo3 interaction for cargo recycling via endosomes and the TGN, where β'-COP serves as a molecular platform to coordinate binding to multiple proteins, including Glo3, Arf1, and the COPI F-subcomplex.
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Affiliation(s)
- Boyang Xie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Clara Guillem
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Swapneeta S. Date
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Cameron I. Cohen
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Christian Jung
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Amy K. Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Jordan T. Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lauren P. Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
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Wang Y, Lupashin VV, Graham TR. Correction to: Golgi. Methods Mol Biol 2023; 2557:C1. [PMID: 36763332 DOI: 10.1007/978-1-0716-2639-9_48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
| | - Vladimir V Lupashin
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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Jimenez M, Best JT, Date SS, Graham TR. Quantification of Golgi Protein Mislocalization to the Budding Yeast Vacuole. Methods Mol Biol 2023; 2557:17-28. [PMID: 36512206 DOI: 10.1007/978-1-0716-2639-9_2] [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: 06/17/2023]
Abstract
The localization of proteins to the Golgi complex is a dynamic process requiring sorting signals in the cytosolic domains of resident Golgi proteins and retrograde vesicular trafficking. Disruptions in these signals or in the retrograde pathways often lead to mislocalization of Golgi proteins to the vacuole in budding yeast. The extent of vacuolar mislocalization can be quantified through colocalization of GFP-tagged Golgi proteins with fluorescent dyes that mark either the vacuole limiting membrane or the vacuole lumen. Manders' colocalization coefficient (MCC) is a useful tool for quantifying the degree of colocalization. However, the dilution of fluorescence signal intensity that occurs when GFP-tagged Golgi proteins mislocalize to the much larger vacuole is problematic for thresholding the images prior to calculating the MCC. In this chapter, we describe the use of Multi-Otsu thresholding in ImageJ to quantify the degree of GFP-tagged protein mislocalization to the vacuole. Furthermore, these methods can be applied to other colocalization events within the cell.
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Affiliation(s)
- Mariana Jimenez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Jordan T Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Swapneeta S Date
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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11
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Jain BK, Wagner AS, Reynolds TB, Graham TR. Lipid Transport by Candida albicans Dnf2 Is Required for Hyphal Growth and Virulence. Infect Immun 2022; 90:e0041622. [PMID: 36214556 PMCID: PMC9670988 DOI: 10.1128/iai.00416-22] [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] [Received: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is a common cause of human mucosal yeast infections, and invasive candidiasis can be fatal. Antifungal medications are limited, but those targeting the pathogen cell wall or plasma membrane have been effective. Therefore, virulence factors controlling membrane biogenesis are potential targets for drug development. P4-ATPases contribute to membrane biogenesis by selecting and transporting specific lipids from the extracellular leaflet to the cytoplasmic leaflet of the bilayer to generate lipid asymmetry. A subset of heterodimeric P4-ATPases, including Dnf1-Lem3 and Dnf2-Lem3 from Saccharomyces cerevisiae, transport phosphatidylcholine (PC), phosphatidylethanolamine (PE), and the sphingolipid glucosylceramide (GlcCer). GlcCer is a critical lipid for Candida albicans polarized growth and virulence, but the role of GlcCer transporters in virulence has not been explored. Here, we show that the Candida albicans Dnf2 (CaDnf2) requires association with CaLem3 to form a functional transporter and flip fluorescent derivatives of GlcCer, PC, and PE across the plasma membrane. Mutation of conserved substrate-selective residues in the membrane domain strongly abrogates GlcCer transport and partially disrupts PC transport by CaDnf2. Candida strains harboring dnf2-null alleles (dnf2ΔΔ) or point mutations that disrupt substrate recognition exhibit defects in yeast-to-hypha growth transition, filamentous growth, and virulence in systemically infected mice. The influence of CaDNF1 deletion on the morphological phenotypes is negligible, although the dnf1ΔΔ dnf2ΔΔ strain was less virulent than the dnf2ΔΔ strain. These results indicate that the transport of GlcCer and/or PC by plasma membrane P4-ATPases is important for the pathogenicity of Candida albicans.
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Affiliation(s)
- Bhawik K. Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Andrew S. Wagner
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Todd B. Reynolds
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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12
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Date SS, Xu P, Hepowit NL, Diab NS, Best J, Xie B, Du J, Strieter ER, Jackson LP, MacGurn JA, Graham TR. Ubiquitination drives COPI priming and Golgi SNARE localization. eLife 2022; 11:e80911. [PMID: 35904239 PMCID: PMC9374436 DOI: 10.7554/elife.80911] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/01/2022] [Indexed: 11/15/2022] Open
Abstract
Deciphering mechanisms controlling SNARE localization within the Golgi complex is crucial to understanding protein trafficking patterns within the secretory pathway. SNAREs are also thought to prime coatomer protein I (COPI) assembly to ensure incorporation of these essential cargoes into vesicles, but the regulation of these events is poorly understood. Here, we report roles for ubiquitin recognition by COPI in SNARE trafficking and in stabilizing interactions between Arf, COPI, and Golgi SNAREs in Saccharomyces cerevisiae. The ability of COPI to bind ubiquitin, but not the dilysine motif, through its N-terminal WD repeat domain of β'-COP or through an unrelated ubiquitin-binding domain is essential for the proper localization of Golgi SNAREs Bet1 and Gos1. We find that COPI, the ArfGAP Glo3, and multiple Golgi SNAREs are ubiquitinated. Notably, the binding of Arf and COPI to Gos1 is markedly enhanced by ubiquitination of these components. Glo3 is proposed to prime COPI-SNARE interactions; however, Glo3 is not enriched in the ubiquitin-stabilized SNARE-Arf-COPI complex but is instead enriched with COPI complexes that lack SNAREs. These results support a new model for how posttranslational modifications drive COPI priming events crucial for Golgi SNARE localization.
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Affiliation(s)
- Swapneeta S Date
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Peng Xu
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Nathaniel L Hepowit
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
| | - Nicholas S Diab
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Jordan Best
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Boyang Xie
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Jiale Du
- Department of Chemistry, University of Massachusetts AmherstAmherstUnited States
| | - Eric R Strieter
- Department of Chemistry, University of Massachusetts AmherstAmherstUnited States
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
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13
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Norris AC, Yazlovitskaya E, Zhu L, Rose B, Yu S, McLean JA, Stafford J, Graham TR. ATP10A has a protective and sex‐specific role in lipid metabolism. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l7439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Lin Zhu
- MedicineVanderbilt University Medical CenterNashvilleTN
| | | | - Sophia Yu
- MedicineVanderbilt University Medical CenterNashvilleTN
| | | | - John Stafford
- MedicineVanderbilt University Medical CenterNashvilleTN
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14
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Steenwyk JL, Phillips MA, Yang F, Date SS, Graham TR, Berman J, Hittinger CT, Rokas A. An orthologous gene coevolution network provides insight into eukaryotic cellular and genomic structure and function. Sci Adv 2022; 8:eabn0105. [PMID: 35507651 PMCID: PMC9067921 DOI: 10.1126/sciadv.abn0105] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
The evolutionary rates of functionally related genes often covary. We present a gene coevolution network inferred from examining nearly 3 million orthologous gene pairs from 332 budding yeast species spanning ~400 million years of evolution. Network modules provide insight into cellular and genomic structure and function. Examination of the phenotypic impact of network perturbation using deletion mutant data from the baker's yeast Saccharomyces cerevisiae, which were obtained from previously published studies, suggests that fitness in diverse environments is affected by orthologous gene neighborhood and connectivity. Mapping the network onto the chromosomes of S. cerevisiae and Candida albicans revealed that coevolving orthologous genes are not physically clustered in either species; rather, they are often located on different chromosomes or far apart on the same chromosome. The coevolution network captures the hierarchy of cellular structure and function, provides a roadmap for genotype-to-phenotype discovery, and portrays the genome as a linked ensemble of genes.
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Affiliation(s)
- Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Megan A. Phillips
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Feng Yang
- Shmunis School of Biomedical and Cancer Research, Tel Aviv University, Ramat Aviv, Israel
- Department of Pharmacology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Swapneeta S. Date
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Judith Berman
- Shmunis School of Biomedical and Cancer Research, Tel Aviv University, Ramat Aviv, Israel
| | - Chris Todd Hittinger
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J.F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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15
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Graham TR. AP-3 shows off its flexibility for the cryo-EM camera. J Biol Chem 2021; 298:101491. [PMID: 34902351 PMCID: PMC8801477 DOI: 10.1016/j.jbc.2021.101491] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2021] [Indexed: 11/29/2022] Open
Abstract
The tetrameric adaptor protein AP-3 is critical for the transport of proteins to lysosomes and lysosome-related organelles. The structures of homologous adaptors AP-1 and AP-2 have revealed a closed-to-open conformational change upon membrane recruitment and phosphoinositide binding. Recently, Schoppe et al. reported the first cryo-EM structures of AP-3 from budding yeast and described remarkably flexible solution structures that are all in the open conformation. The apparent lack of a closed conformational state, the first such description in the literature, allows AP-3 to be more reliant on cargo interaction for its initial membrane recruitment compared with AP-1.
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Affiliation(s)
- Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
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16
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Bai L, Jain BK, You Q, Duan HD, Takar M, Graham TR, Li H. Structural basis of the P4B ATPase lipid flippase activity. Nat Commun 2021; 12:5963. [PMID: 34645814 PMCID: PMC8514546 DOI: 10.1038/s41467-021-26273-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/28/2021] [Indexed: 11/23/2022] Open
Abstract
P4 ATPases are lipid flippases that are phylogenetically grouped into P4A, P4B and P4C clades. The P4A ATPases are heterodimers composed of a catalytic α-subunit and accessory β-subunit, and the structures of several heterodimeric flippases have been reported. The S. cerevisiae Neo1 and its orthologs represent the P4B ATPases, which function as monomeric flippases without a β-subunit. It has been unclear whether monomeric flippases retain the architecture and transport mechanism of the dimeric flippases. Here we report the structure of a P4B ATPase, Neo1, in its E1-ATP, E2P-transition, and E2P states. The structure reveals a conserved architecture as well as highly similar functional intermediate states relative to dimeric flippases. Consistently, structure-guided mutagenesis of residues in the proposed substrate translocation path disrupted Neo1’s ability to establish membrane asymmetry. These observations indicate that evolutionarily distant P4 ATPases use a structurally conserved mechanism for substrate transport. The P4 ATPase lipid flippases play a crucial role in membrane biogenesis. Here the authors report the structure of the monomeric P4B ATPase Neo1 in several states, clarifying the mechanism of substrate transport.
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Affiliation(s)
- Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China.
| | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Qinglong You
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - H Diessel Duan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Mehmet Takar
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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17
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Jain BK, Roland BP, Graham TR. Exofacial membrane composition and lipid metabolism regulates plasma membrane P4-ATPase substrate specificity. J Biol Chem 2020; 295:17997-18009. [PMID: 33060204 PMCID: PMC7939387 DOI: 10.1074/jbc.ra120.014794] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/22/2020] [Indexed: 01/21/2023] Open
Abstract
The plasma membrane of a cell is characterized by an asymmetric distribution of lipid species across the exofacial and cytofacial aspects of the bilayer. Regulation of membrane asymmetry is a fundamental characteristic of membrane biology and is crucial for signal transduction, vesicle transport, and cell division. The type IV family of P-ATPases, or P4-ATPases, establishes membrane asymmetry by selection and transfer of a subset of membrane lipids from the lumenal or exofacial leaflet to the cytofacial aspect of the bilayer. It is unclear how P4-ATPases sort through the spectrum of membrane lipids to identify their desired substrate(s) and how the membrane environment modulates this activity. Therefore, we tested how the yeast plasma membrane P4-ATPase, Dnf2, responds to changes in membrane composition induced by perturbation of endogenous lipid biosynthetic pathways or exogenous application of lipid. The primary substrates of Dnf2 are glucosylceramide (GlcCer) and phosphatidylcholine (PC, or their lyso-lipid derivatives), and we find that these substrates compete with each other for transport. Acutely inhibiting sphingolipid synthesis using myriocin attenuates transport of exogenously applied GlcCer without perturbing PC transport. Deletion of genes controlling later steps of glycosphingolipid production also perturb GlcCer transport to a greater extent than PC transport. In contrast, perturbation of ergosterol biosynthesis reduces PC and GlcCer transport equivalently. Surprisingly, application of lipids that are poor transport substrates differentially affects PC and GlcCer transport by Dnf2, thus altering substrate preference. Our data indicate that Dnf2 exhibits exquisite sensitivity to the membrane composition, thus providing feedback onto the function of the P4-ATPases.
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Affiliation(s)
- Bhawik Kumar Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Bartholomew P Roland
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
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18
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Bai L, You Q, Jain BK, Duan HD, Kovach A, Graham TR, Li H. Transport mechanism of P4 ATPase phosphatidylcholine flippases. eLife 2020; 9:62163. [PMID: 33320091 PMCID: PMC7773333 DOI: 10.7554/elife.62163] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
The P4 ATPases use ATP hydrolysis to transport large lipid substrates across lipid bilayers. The structures of the endosome- and Golgi-localized phosphatidylserine flippases—such as the yeast Drs2 and human ATP8A1—have recently been reported. However, a substrate-binding site on the cytosolic side has not been found, and the transport mechanisms of P4 ATPases with other substrates are unknown. Here, we report structures of the S. cerevisiae Dnf1–Lem3 and Dnf2–Lem3 complexes. We captured substrate phosphatidylcholine molecules on both the exoplasmic and cytosolic sides and found that they have similar structures. Unexpectedly, Lem3 contributes to substrate binding. The conformational transitions of these phosphatidylcholine transporters match those of the phosphatidylserine transporters, suggesting a conserved mechanism among P4 ATPases. Dnf1/Dnf2 have a unique P domain helix-turn-helix insertion that is important for function. Therefore, P4 ATPases may have retained an overall transport mechanism while evolving distinct features for different lipid substrates.
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Affiliation(s)
- Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Qinglong You
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - H Diessel Duan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Amanda Kovach
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
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19
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Best JT, Xu P, McGuire JG, Leahy SN, Graham TR. Yeast synaptobrevin, Snc1, engages distinct routes of postendocytic recycling mediated by a sorting nexin, Rcy1-COPI, and retromer. Mol Biol Cell 2020; 31:944-962. [PMID: 32074001 PMCID: PMC7185969 DOI: 10.1091/mbc.e19-05-0290] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 05/31/2019] [Revised: 01/31/2020] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
Abstract
The budding yeast v-SNARE, Snc1, mediates fusion of exocytic vesicles to the plasma membrane (PM) and is subsequently recycled back to the Golgi. Postendocytic recycling of Snc1 requires a phospholipid flippase (Drs2-Cdc50), an F-box protein (Rcy1), a sorting nexin (Snx4-Atg20), and the COPI coat complex. A portion of the endocytic tracer FM4-64 is also recycled back to the PM after internalization. However, the relationship between Snx4, Drs2, Rcy1, and COPI in recycling Snc1 or FM4-64 is unclear. Here we show that rcy1∆ and drs2∆ single mutants, or a COPI mutant deficient in ubiquitin binding, display a defect in recycling FM4-64 while snx4∆ cells recycle FM4-64 normally. The addition of latrunculin A to acutely inhibit endocytosis shows that rcy1∆ and snx4∆ single mutants retain the ability to recycle Snc1, but a snx4∆rcy1∆ mutant substantially blocks export. Additional deletion of a retromer subunit completely eliminates recycling of Snc1 in the triple mutant (snx4∆rcy1∆vps35∆). A minor role for retromer in Snc1 recycling can also be observed in single and double mutants harboring vps35∆. These data support the existence of three distinct and parallel recycling pathways mediated by Drs2/Rcy1/COPI, Snx4-Atg20, and retromer that retrieve an exocytic v-SNARE from the endocytic pathway to the Golgi.
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Affiliation(s)
- Jordan T. Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Jack G. McGuire
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
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20
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Takar M, Huang Y, Graham TR. The PQ-loop protein Any1 segregates Drs2 and Neo1 functions required for viability and plasma membrane phospholipid asymmetry. J Lipid Res 2019; 60:1032-1042. [PMID: 30824614 PMCID: PMC6495175 DOI: 10.1194/jlr.m093526] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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] [Received: 02/22/2019] [Indexed: 02/06/2023] Open
Abstract
Membrane asymmetry is a key organizational feature of the plasma membrane. Type IV P-type ATPases (P4-ATPases) are phospholipid flippases that establish membrane asymmetry by translocating phospholipids, such as phosphatidylserine (PS) and phospatidylethanolamine, from the exofacial leaflet to the cytosolic leaflet. Saccharomyces cerevisiae expresses five P4-ATPases: Drs2, Neo1, Dnf1, Dnf2, and Dnf3. The inactivation of Neo1 is lethal, suggesting Neo1 mediates an essential function not exerted by the other P4-ATPases. However, the disruption of ANY1, which encodes a PQ-loop membrane protein, allows the growth of neo1Δ and reveals functional redundancy between Golgi-localized Neo1 and Drs2. Here we show Drs2 PS flippase activity is required to support neo1Δ any1Δ viability. Additionally, a Dnf1 variant with enhanced PS flipping ability can replace Drs2 and Neo1 function in any1Δ cells. any1Δ also suppresses drs2Δ growth defects but not the loss of membrane asymmetry. Any1 overexpression perturbs the growth of cells but does not disrupt membrane asymmetry. Any1 coimmunoprecipitates with Neo1, an association prevented by the Any1-inactivating mutation D84G. These results indicate a critical role for PS flippase activity in Golgi membranes to sustain viability and suggests Any1 regulates Golgi membrane remodeling through protein-protein interactions rather than a previously proposed scramblase activity.
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Affiliation(s)
- Mehmet Takar
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Yannan Huang
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235.
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21
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Best JT, Xu P, Graham TR. Phospholipid flippases in membrane remodeling and transport carrier biogenesis. Curr Opin Cell Biol 2019; 59:8-15. [PMID: 30897446 DOI: 10.1016/j.ceb.2019.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 12/21/2022]
Abstract
Molecular mechanisms underlying the formation of multiple classes of transport carriers or vesicles from Golgi and endosomal membranes remain poorly understood. However, one theme that has emerged over three decades is the dramatic influence of membrane lipid remodeling on transport mechanisms. A large cohort of lipid transfer proteins, lipid transporters, and lipid modifying enzymes are linked to protein sorting, carrier formation and SNARE-mediated fusion events. Here, we focus on one type of lipid transporter, phospholipid flippases in the type IV P-type ATPase (P4-ATPase) family, and discuss recent advances in defining P4-ATPase influences on membrane remodeling and vesicular transport.
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Affiliation(s)
- Jordan T Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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22
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Roland BP, Naito T, Best JT, Arnaiz-Yépez C, Takatsu H, Yu RJ, Shin HW, Graham TR. Yeast and human P4-ATPases transport glycosphingolipids using conserved structural motifs. J Biol Chem 2018; 294:1794-1806. [PMID: 30530492 DOI: 10.1074/jbc.ra118.005876] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/29/2018] [Indexed: 12/21/2022] Open
Abstract
Lipid transport is an essential process with manifest importance to human health and disease. Phospholipid flippases (P4-ATPases) transport lipids across the membrane bilayer and are involved in signal transduction, cell division, and vesicular transport. Mutations in flippase genes cause or contribute to a host of diseases, such as cholestasis, neurological deficits, immunological dysfunction, and metabolic disorders. Genome-wide association studies have shown that ATP10A and ATP10D variants are associated with an increased risk of diabetes, obesity, myocardial infarction, and atherosclerosis. Moreover, ATP10D SNPs are associated with elevated levels of glucosylceramide (GlcCer) in plasma from diverse European populations. Although sphingolipids strongly contribute to metabolic disease, little is known about how GlcCer is transported across cell membranes. Here, we identify a conserved clade of P4-ATPases from Saccharomyces cerevisiae (Dnf1, Dnf2), Schizosaccharomyces pombe (Dnf2), and Homo sapiens (ATP10A, ATP10D) that transport GlcCer bearing an sn2 acyl-linked fluorescent tag. Further, we establish structural determinants necessary for recognition of this sphingolipid substrate. Using enzyme chimeras and site-directed mutagenesis, we observed that residues in transmembrane (TM) segments 1, 4, and 6 contribute to GlcCer selection, with a conserved glutamine in the center of TM4 playing an essential role. Our molecular observations help refine models for substrate translocation by P4-ATPases, clarify the relationship between these flippases and human disease, and have fundamental implications for membrane organization and sphingolipid homeostasis.
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Affiliation(s)
- Bartholomew P Roland
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Tomoki Naito
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Jordan T Best
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Cayetana Arnaiz-Yépez
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Hiroyuki Takatsu
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Roger J Yu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Hye-Won Shin
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Todd R Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
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23
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Xu P, Hankins HM, MacDonald C, Erlinger SJ, Frazier MN, Diab NS, Piper RC, Jackson LP, MacGurn JA, Graham TR. COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal. eLife 2017; 6:28342. [PMID: 29058666 PMCID: PMC5663479 DOI: 10.7554/elife.28342] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 10/22/2017] [Indexed: 11/17/2022] Open
Abstract
The COPI coat forms transport vesicles from the Golgi complex and plays a poorly defined role in endocytic trafficking. Here we show that COPI binds K63-linked polyubiquitin and this interaction is crucial for trafficking of a ubiquitinated yeast SNARE (Snc1). Snc1 is a v-SNARE that drives fusion of exocytic vesicles with the plasma membrane, and then recycles through the endocytic pathway to the Golgi for reuse in exocytosis. Removal of ubiquitin from Snc1, or deletion of a β'-COP subunit propeller domain that binds K63-linked polyubiquitin, disrupts Snc1 recycling causing aberrant accumulation in internal compartments. Moreover, replacement of the β'-COP propeller domain with unrelated ubiquitin-binding domains restores Snc1 recycling. These results indicate that ubiquitination, a modification well known to target membrane proteins to the lysosome or vacuole for degradation, can also function as recycling signal to sort a SNARE into COPI vesicles in a non-degradative pathway.
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Affiliation(s)
- Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Hannah M Hankins
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Chris MacDonald
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States
| | - Samuel J Erlinger
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Meredith N Frazier
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Nicholas S Diab
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
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24
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van Leeuwen J, Pons C, Mellor JC, Yamaguchi TN, Friesen H, Koschwanez J, Ušaj MM, Pechlaner M, Takar M, Ušaj M, VanderSluis B, Andrusiak K, Bansal P, Baryshnikova A, Boone CE, Cao J, Cote A, Gebbia M, Horecka G, Horecka I, Kuzmin E, Legro N, Liang W, van Lieshout N, McNee M, San Luis BJ, Shaeri F, Shuteriqi E, Sun S, Yang L, Youn JY, Yuen M, Costanzo M, Gingras AC, Aloy P, Oostenbrink C, Murray A, Graham TR, Myers CL, Andrews BJ, Roth FP, Boone C. Exploring genetic suppression interactions on a global scale. Science 2017; 354:354/6312/aag0839. [PMID: 27811238 DOI: 10.1126/science.aag0839] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 10/04/2016] [Indexed: 12/21/2022]
Abstract
Genetic suppression occurs when the phenotypic defects caused by a mutation in a particular gene are rescued by a mutation in a second gene. To explore the principles of genetic suppression, we examined both literature-curated and unbiased experimental data, involving systematic genetic mapping and whole-genome sequencing, to generate a large-scale suppression network among yeast genes. Most suppression pairs identified novel relationships among functionally related genes, providing new insights into the functional wiring diagram of the cell. In addition to suppressor mutations, we identified frequent secondary mutations,in a subset of genes, that likely cause a delay in the onset of stationary phase, which appears to promote their enrichment within a propagating population. These findings allow us to formulate and quantify general mechanisms of genetic suppression.
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Affiliation(s)
- Jolanda van Leeuwen
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Carles Pons
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA.,Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute for Science and Technology, Barcelona, Catalonia, Spain
| | - Joseph C Mellor
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Takafumi N Yamaguchi
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Helena Friesen
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - John Koschwanez
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Mojca Mattiazzi Ušaj
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Maria Pechlaner
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Mehmet Takar
- Department of Biological Sciences, Vanderbilt University, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Matej Ušaj
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Benjamin VanderSluis
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Kerry Andrusiak
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Pritpal Bansal
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Anastasia Baryshnikova
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Claire E Boone
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Jessica Cao
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Atina Cote
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Marinella Gebbia
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Gene Horecka
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Ira Horecka
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Elena Kuzmin
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Nicole Legro
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Wendy Liang
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Natascha van Lieshout
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Margaret McNee
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Bryan-Joseph San Luis
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Fatemeh Shaeri
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Ermira Shuteriqi
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Song Sun
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Lu Yang
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Ji-Young Youn
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Michael Yuen
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Michael Costanzo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Patrick Aloy
- Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute for Science and Technology, Barcelona, Catalonia, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia, Spain
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Andrew Murray
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA. .,Canadian Institute for Advanced Research, 180 Dundas Street West, Toronto, Ontario M5G 1Z8, Canada
| | - Brenda J Andrews
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada. .,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Frederick P Roth
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada. .,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Canadian Institute for Advanced Research, 180 Dundas Street West, Toronto, Ontario M5G 1Z8, Canada.,Department of Computer Science, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Charles Boone
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada. .,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Canadian Institute for Advanced Research, 180 Dundas Street West, Toronto, Ontario M5G 1Z8, Canada
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25
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Senanayake EL, Smith GD, Rooney SJ, Graham TR, Greaves I. Chest drains – An overview. Trauma 2017. [DOI: 10.1177/1460408616676505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chest drains are used in a number of circumstances for the treatment of specific conditions and also for symptomatic relief, and hence insertion of a chest drain can be a life-saving intervention. Therefore, it is imperative that every hospital doctor is familiar with the indications and the principles of safe chest drain insertion. The knowledge of chest drain management following insertion is equally essential. Appropriate chest drain insertion and management underpins the management of chest trauma. Appropriate chest drain management will allow for resolution and management of the underlying clinical condition. This review article outlines the indications, contraindications, and principles of chest drain insertion. Furthermore, it provides an overview of chest drain management and associated complications. Although this review refers to a surgically placed chest drain, the same principles can be applied to a chest drain that is inserted percutaneously.
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Affiliation(s)
- EL Senanayake
- Department of Cardiac Surgery, University Hospitals Birmingham, Birmingham, UK
- Department of Cardiovascular Medicine, University of Birmingham, UK
| | - GD Smith
- Department of Academic Emergency Medicine, James Cook University Hospital Middlesbrough, UK
| | - SJ Rooney
- Department of Cardiovascular Medicine, University of Birmingham, UK
| | - TR Graham
- Department of Cardiovascular Medicine, University of Birmingham, UK
| | - I Greaves
- Department of Academic Emergency Medicine, James Cook University Hospital Middlesbrough, UK
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26
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Abstract
Cellular membranes display a diversity of functions that are conferred by the unique composition and organization of their proteins and lipids. One important aspect of lipid organization is the asymmetric distribution of phospholipids (PLs) across the plasma membrane. The unequal distribution of key PLs between the cytofacial and exofacial leaflets of the bilayer creates physical surface tension that can be used to bend the membrane; and like Ca2+, a chemical gradient that can be used to transduce biochemical signals. PL flippases in the type IV P-type ATPase (P4-ATPase) family are the principle transporters used to set and repair this PL gradient and the asymmetric organization of these membranes are encoded by the substrate specificity of these enzymes. Thus, understanding the mechanisms of P4-ATPase substrate specificity will help reveal their role in membrane organization and cell biology. Further, decoding the structural determinants of substrate specificity provides investigators the opportunity to mutationally tune this specificity to explore the role of particular PL substrates in P4-ATPase cellular functions. This work reviews the role of P4-ATPases in membrane biology, presents our current understanding of P4-ATPase substrate specificity, and discusses how these fundamental aspects of P4-ATPase enzymology may be used to enhance our knowledge of cellular membrane biology.
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Affiliation(s)
- Bartholomew P. Roland
- Vanderbilt University, Department of Biological Sciences, 1161 21st Ave South, Nashville, TN 37235
| | - Todd R. Graham
- Vanderbilt University, Department of Biological Sciences, 1161 21st Ave South, Nashville, TN 37235
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27
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Abstract
Myocardial contusion can be a difficult diagnosis to make. There is currently no gold standard of investigation that allows its accurate diagnosis in the clinical setting. Trauma surgeons need to have a high degree of clinical suspicion when dealing with patients who have received blunt thoracic injuries in order that the diagnosis of myocardial contusion may be made. In this article we discuss the diagnosis, potential complications and investigation of patients with suspected myocardial contusion and also present a fl ow diagram for the possible management of patients with trauma who may have suspected myocardial contusion.
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Affiliation(s)
- AM Ranasinghe
- Department of Cardiothoracic Surgery, University Hospital Birmingham NHS Trust, Birmingham, UK
| | - ME Lewis
- Department of Cardiothoracic Surgery, University Hospital Birmingham NHS Trust, Birmingham, UK
| | - TR Graham
- Department of Cardiothoracic Surgery, University Hospital Birmingham NHS Trust, Birmingham, UK,
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28
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Wu Y, Takar M, Cuentas-Condori AA, Graham TR. Neo1 and phosphatidylethanolamine contribute to vacuole membrane fusion in Saccharomyces cerevisiae. Cell Logist 2016; 6:e1228791. [PMID: 27738552 PMCID: PMC5058351 DOI: 10.1080/21592799.2016.1228791] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/05/2016] [Accepted: 08/19/2016] [Indexed: 02/04/2023]
Abstract
NEO1 is an essential gene in budding yeast and belongs to a highly conserved subfamily of P-type ATPase genes that encode phospholipid flippases. Inactivation of temperature sensitive neo1ts alleles produces pleiomorphic defects in the secretory and endocytic pathways, including fragmented vacuoles. A screen for multicopy suppressors of neo1-2ts growth defects yielded YPT7, which encodes a Rab7 homolog involved in SNARE-dependent vacuolar fusion. YPT7 suppressed the vacuole fragmentation phenotype of neo1-2, but did not suppress Golgi-associated protein trafficking defects. Neo1 localizes to Golgi and endosomal membranes and was only observed in the vacuole membrane, where Ypt7 localizes, in retromer mutants or when highly overexpressed in wild-type cells. Phosphatidylethanolamine (PE) has been implicated in Ypt7-dependent vacuolar membrane fusion in vitro and is a potential transport substrate of Neo1. Strains deficient in PE synthesis (psd1Δ psd2Δ) displayed fragmented vacuoles and the neo1-2 fragmented vacuole phenotype was also suppressed by overexpression of PSD2, encoding a phosphatidylserine decarboxylase that produces PE at endosomes. In contrast, neo1-2 was not suppressed by overexpression of VPS39, an effector of Ypt7 that forms a membrane contact site potentially involved in PE transfer between vacuoles and mitochondria. These results support the crucial role of PE in vacuole membrane fusion and implicate Neo1 in concentrating PE in the cytosolic leaflet of Golgi and endosomes, and ultimately the vacuole membrane.
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Affiliation(s)
- Yuantai Wu
- Department of Biological Sciences, Vanderbilt University , Nashville, TN, USA
| | - Mehmet Takar
- Department of Biological Sciences, Vanderbilt University , Nashville, TN, USA
| | | | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University , Nashville, TN, USA
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29
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Abstract
The majority of thoracic injuries encountered in the UK are secondary to blunt trauma following motor vehicle accidents. Rib fractures account for more than half of these injuries. Sternal fractures, although less common, have an increased incidence following the implementation of seat belt legislation. Both rib and sternal fractures may compromise ventilation by a variety of mechanisms. Pain leads to a reduction in lung expansion and sputum retention. Fractured ribs may cause penetrating injury resulting in a haemopneumothorax. There may also be asso ciated pulmonary contusion and flail chest, which further compromises ventilation. Sternal and rib fractures are managed by a number of specialties including accident and emergency staff, cardiothoracic and trauma surgeons, as well as anaesthetists and intensivists. The management of rib and sternal fractures principally consists of the identification and treatment of associated injuries, appropriate respiratory care and symptomatic relief. This article reviews the literature on the investigations and management of the patient with rib and sternal fractures.
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Affiliation(s)
- NJ Howell
- Department of Cardiothoracic Surgery, University Hospital NHS Trust, Birmingham, UK
| | - AM Ranasinghe
- Department of Cardiothoracic Surgery, University Hospital NHS Trust, Birmingham, UK
| | - TR Graham
- Department of Cardiothoracic Surgery, University Hospital NHS Trust, Birmingham, UK
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30
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Abstract
The postperfusion syndrome, haemolytic anaemia and thrombocytopenic purpura following open heart surgery have all been attributed to acute cytomegalovirus (CMV) infection,'-3 usually acquired from perioperative transfusions of whole blood. Increased susceptibility of bacterial infections has been described,4 but only in patients who have undergone cardiac transplantation and consequently received immunosuppressive therapy. Studies have shown that CMV can suppress cell-mediated immunity in vivo and in vitro5 and impairment of neutrophil migration has been demonstrated in CMV infected mice.6 We describe a patient with impaired polymorph function associated with an acute CMV infection following aortic valve replacement.
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Affiliation(s)
- FK Gould
- Freeman Hospital, Newcastle-upon-Tyne
| | - TR Graham
- Freeman Hospital, Newcastle-upon-Tyne
| | | | - MP Holden
- Freeman Hospital, Newcastle-upon-Tyne
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31
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Abstract
'For many reasons clinicians hesitate to employ mechanical devices of unproved efficacy except in the most critically ill patients and then only as a desperate measure. These approaches accounted for a substantial lag time between intra-aortic balloon pump availability and widespread utilization. Ventricular assist devices, recently approved for initial clinical trials, face the same dilemmas'. Norman, 1977.1
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Affiliation(s)
- Jac Chalmers
- Department of Cardiothoracic Surgery, The London Hospital
| | - TR Graham
- Department of Cardiothoracic Surgery, The London Hospital
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32
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Takar M, Wu Y, Graham TR. The Essential Neo1 Protein from Budding Yeast Plays a Role in Establishing Aminophospholipid Asymmetry of the Plasma Membrane. J Biol Chem 2016; 291:15727-39. [PMID: 27235400 DOI: 10.1074/jbc.m115.686253] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic organisms typically express multiple type IV P-type ATPases (P4-ATPases), which establish plasma membrane asymmetry by flipping specific phospholipids from the exofacial to the cytosolic leaflet. Saccharomyces cerevisiae, for example, expresses five P4-ATPases, including Neo1, Drs2, Dnf1, Dnf2, and Dnf3. Neo1 is thought to be a phospholipid flippase, although there is currently no experimental evidence that Neo1 catalyzes this activity or helps establish membrane asymmetry. Here, we use temperature-conditional alleles (neo1(ts)) to test whether Neo1 deficiency leads to loss of plasma membrane asymmetry. Wild-type (WT) yeast normally restrict most of the phosphatidylserine (PS) and phosphatidylethanolamine (PE) to the inner cytosolic leaflet of the plasma membrane. However, the neo1-1(ts) and neo1-2(ts) mutants display a loss of PS and PE asymmetry at permissive growth temperatures as measured by hypersensitivity to pore-forming toxins that target PS (papuamide A) or PE (duramycin) exposed in the extracellular leaflet. When shifted to a semi-permissive growth temperature, the neo1-1(ts) mutant became extremely hypersensitive to duramycin, although the sensitivity to papuamide A was unchanged, indicating preferential exposure of PE. This loss of asymmetry occurs despite the presence of other flippases that flip PS and/or PE. Even when overexpressed, Drs2 and Dnf1 were unable to correct the loss of asymmetry caused by neo1(ts) However, modest overexpression of Neo1 weakly suppressed loss of membrane asymmetry caused by drs2Δ with a more significant correction of PE asymmetry than PS. These results indicate that Neo1 plays an important role in establishing PS and PE plasma membrane asymmetry in budding yeast.
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Affiliation(s)
- Mehmet Takar
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Yuantai Wu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Todd R Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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33
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Hankins HM, Sere YY, Diab NS, Menon AK, Graham TR. Phosphatidylserine translocation at the yeast trans-Golgi network regulates protein sorting into exocytic vesicles. Mol Biol Cell 2015; 26:4674-85. [PMID: 26466678 PMCID: PMC4678023 DOI: 10.1091/mbc.e15-07-0487] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/06/2015] [Indexed: 11/16/2022] Open
Abstract
Protein sorting into exocytic vesicles at the yeast trans-Golgi network is believed to be mediated by their coalescence with specific lipids, but how this event is regulated is poorly understood. It is shown that phosphatidylserine flip by Drs2 is required for efficient sorting of the plasma membrane proteins Pma1 and Can1 into exocytic vesicles. Sorting of plasma membrane proteins into exocytic vesicles at the yeast trans-Golgi network (TGN) is believed to be mediated by their coalescence with specific lipids, but how these membrane-remodeling events are regulated is poorly understood. Here we show that the ATP-dependent phospholipid flippase Drs2 is required for efficient segregation of cargo into exocytic vesicles. The plasma membrane proteins Pma1 and Can1 are missorted from the TGN to the vacuole in drs2∆ cells. We also used a combination of flippase mutants that either gain or lose the ability to flip phosphatidylserine (PS) to determine that PS flip by Drs2 is its critical function in this sorting event. The primary role of PS flip at the TGN appears to be to control the oxysterol-binding protein homologue Kes1/Osh4 and regulate ergosterol subcellular distribution. Deletion of KES1 suppresses plasma membrane–missorting defects and the accumulation of intracellular ergosterol in drs2 mutants. We propose that PS flip is part of a homeostatic mechanism that controls sterol loading and lateral segregation of protein and lipid domains at the TGN.
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Affiliation(s)
- Hannah M Hankins
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Yves Y Sere
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Nicholas S Diab
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
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34
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Graham TR. Control of Membrane Asymmetry by P4-ATPases. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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35
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Hankins HM, Baldridge RD, Xu P, Graham TR. Role of flippases, scramblases and transfer proteins in phosphatidylserine subcellular distribution. Traffic 2014; 16:35-47. [PMID: 25284293 DOI: 10.1111/tra.12233] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 12/11/2022]
Abstract
It is well known that lipids are heterogeneously distributed throughout the cell. Most lipid species are synthesized in the endoplasmic reticulum (ER) and then distributed to different cellular locations in order to create the distinct membrane compositions observed in eukaryotes. However, the mechanisms by which specific lipid species are trafficked to and maintained in specific areas of the cell are poorly understood and constitute an active area of research. Of particular interest is the distribution of phosphatidylserine (PS), an anionic lipid that is enriched in the cytosolic leaflet of the plasma membrane. PS transport occurs by both vesicular and non-vesicular routes, with members of the oxysterol-binding protein family (Osh6 and Osh7) recently implicated in the latter route. In addition, the flippase activity of P4-ATPases helps build PS membrane asymmetry by preferentially translocating PS to the cytosolic leaflet. This asymmetric PS distribution can be used as a signaling device by the regulated activation of scramblases, which rapidly expose PS on the extracellular leaflet and play important roles in blood clotting and apoptosis. This review will discuss recent advances made in the study of phospholipid flippases, scramblases and PS-specific lipid transfer proteins, as well as how these proteins contribute to subcellular PS distribution.
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Affiliation(s)
- Hannah M Hankins
- Department of Biological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
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36
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Abstract
Drs2p, a yeast type IV P-type ATPase (P4-ATPase), or flippase, couples ATP hydrolysis to phosphatidylserine translocation and the establishment of membrane asymmetry. A previous study has shown that affinity-purified Drs2p, possessing an N-terminal tandem affinity purification tag (TAPN-Drs2), retains ATPase and translocase activity, but Drs2p purified using a C-terminal tag (Drs2-TAPC) was inactive. In this study, we show that the ATPase activity of N-terminally purified Drs2p associates primarily with a proteolyzed form of Drs2p lacking the C-terminal cytosolic tail. Truncation of most of the Drs2p C-terminal tail sequence activates its ATPase activity by ∼4-fold. These observations are consistent with the hypothesis that the C-terminal tail of Drs2p is auto-inhibitory to Drs2p activity. Phosphatidylinositol 4-phosphate (PI(4)P) has been shown to positively regulate Drs2p activity in isolated Golgi membranes through interaction with the C-terminal tail. In proteoliposomes reconstituted with purified, N-terminally TAP-tagged Drs2p, both ATPase and flippase activity were significantly higher in the presence of PI(4)P. In contrast, PI(4)P had no significant effect on the activity of a truncated form of Drs2p, which lacked the C-terminal tail. This work provides the first direct evidence, in a purified system, that a phospholipid flippase is subject to auto-inhibition by its C-terminal tail, which can be relieved by a phosphoinositide to stimulate flippase activity.
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Affiliation(s)
- Xiaoming Zhou
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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37
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Xu P, Baldridge RD, Chi RJ, Burd CG, Graham TR. Phosphatidylserine flipping enhances membrane curvature and negative charge required for vesicular transport. ACTA ACUST UNITED AC 2013; 202:875-86. [PMID: 24019533 PMCID: PMC3776346 DOI: 10.1083/jcb.201305094] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Drs2 flippase increases membrane curvature and anionic phospholipid composition of the membrane by flipping phosphatidylserine, which is critical for vesicular transport between the trans-Golgi network and early endosomes. Vesicle-mediated protein transport between organelles of the secretory and endocytic pathways is strongly influenced by the composition and organization of membrane lipids. In budding yeast, protein transport between the trans-Golgi network (TGN) and early endosome (EE) requires Drs2, a phospholipid translocase in the type IV P-type ATPase family. However, downstream effectors of Drs2 and specific phospholipid substrate requirements for protein transport in this pathway are unknown. Here, we show that the Arf GTPase-activating protein (ArfGAP) Gcs1 is a Drs2 effector that requires a variant of the ArfGAP lipid packing sensor (+ALPS) motif for localization to TGN/EE membranes. Drs2 increases membrane curvature and anionic phospholipid composition of the cytosolic leaflet, both of which are sensed by the +ALPS motif. Using mutant forms of Drs2 and the related protein Dnf1, which alter their ability to recognize phosphatidylserine, we show that translocation of this substrate to the cytosolic leaflet is essential for +ALPS binding and vesicular transport between the EE and the TGN.
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Affiliation(s)
- Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
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38
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Baldridge RD, Xu P, Graham TR. Type IV P-type ATPases distinguish mono- versus diacyl phosphatidylserine using a cytofacial exit gate in the membrane domain. J Biol Chem 2013; 288:19516-27. [PMID: 23709217 PMCID: PMC3707653 DOI: 10.1074/jbc.m113.476911] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [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] [Received: 04/17/2013] [Revised: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
Type IV P-type ATPases (P4-ATPases) use the energy from ATP to "flip" phospholipid across a lipid bilayer, facilitating membrane trafficking events and maintaining the characteristic plasma membrane phospholipid asymmetry. Preferred translocation substrates for the budding yeast P4-ATPases Dnf1 and Dnf2 include lysophosphatidylcholine, lysophosphatidylethanolamine, derivatives of phosphatidylcholine and phosphatidylethanolamine containing a 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD) group on the sn-2 C6 position, and were presumed to include phosphatidylcholine and phosphatidylethanolamine species with two intact acyl chains. We previously identified several mutations in Dnf1 transmembrane (TM) segments 1 through 4 that greatly enhance recognition and transport of NBD phosphatidylserine (NBD-PS). Here we show that most of these Dnf1 mutants cannot flip diacylated PS to the cytosolic leaflet to establish PS asymmetry. However, mutation of a highly conserved asparagine (Asn-550) in TM3 allowed Dnf1 to restore plasma membrane PS asymmetry in a strain deficient for the P4-ATPase Drs2, the primary PS flippase. Moreover, Dnf1 N550 mutants could replace the Drs2 requirement for growth at low temperature. A screen for additional Dnf1 mutants capable of replacing Drs2 function identified substitutions of TM1 and 2 residues, within a region called the exit gate, that permit recognition of dually acylated PS. These TM1, 2, and 3 residues coordinate with the "proline + 4" residue within TM4 to determine substrate preference at the exit gate. Moreover, residues from Atp8a1, a mammalian ortholog of Drs2, in these positions allow PS recognition by Dnf1. These studies indicate that Dnf1 poorly recognizes diacylated phospholipid and define key substitutions enabling recognition of endogenous PS.
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Affiliation(s)
- Ryan D. Baldridge
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Peng Xu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Todd R. Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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Khan JN, Tapp LD, Glancy JM, Prasad N, Bailey MS, Graham TR. Successful surgical treatment of Q fever endocarditis with mitral valve repair. J ROY ARMY MED CORPS 2012; 158:132-4. [PMID: 22860505 DOI: 10.1136/jramc-158-02-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We report a case of successful surgical treatment of Q fever endocarditis with mitral valve repair in a 66-year old retired British soldier. Valve replacement is invariably undertaken in Q fever endocarditis due to the degree of valvular damage and concerns about eradicating the organism, Coxiella burnetii. Our unique case allowed valve repair since pre-existing myxomatous degeneration and subsequent posterior mitral valve leaflet prolapse resulted in significant excess valve tissue, allowing quadrangular resection of the damaged and perforated P2 portion of this leaflet. Follow-up at four years (including three years of antibiotic treatment) has confirmed excellent valve repair, with no echocardiographic, clinical or microbiological evidence of recurrence. We are only the second group to describe valve repair in a patient with chronic Q fever endocarditis. Valve repair is preferable to valve replacement for Q fever endocarditis, if technically possible.
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Affiliation(s)
- J N Khan
- Hereford County Hospital, Wye Valley NHS Trust, Hereford, England, UK
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Sebastian TT, Baldridge RD, Xu P, Graham TR. Phospholipid flippases: building asymmetric membranes and transport vesicles. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:1068-77. [PMID: 22234261 DOI: 10.1016/j.bbalip.2011.12.007] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/14/2011] [Accepted: 12/16/2011] [Indexed: 01/25/2023]
Abstract
Phospholipid flippases in the type IV P-type ATPase family (P4-ATPases) are essential components of the Golgi, plasma membrane and endosomal system that play critical roles in membrane biogenesis. These pumps flip phospholipid across the bilayer to create an asymmetric membrane structure with substrate phospholipids, such as phosphatidylserine and phosphatidylethanolamine, enriched within the cytosolic leaflet. The P4-ATPases also help form transport vesicles that bud from Golgi and endosomal membranes, thereby impacting the sorting and localization of many different proteins in the secretory and endocytic pathways. At the organismal level, P4-ATPase deficiencies are linked to liver disease, obesity, diabetes, hearing loss, neurological deficits, immune deficiency and reduced fertility. Here, we review the biochemical, cellular and physiological functions of P4-ATPases, with an emphasis on their roles in vesicle-mediated protein transport. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
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Affiliation(s)
- Tessy T Sebastian
- Department of Biological Sciences, Vanderbilt University, Nashville TN 37235, USA
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41
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Graham TR, Burd CG. Coordination of Golgi functions by phosphatidylinositol 4-kinases. Trends Cell Biol 2010; 21:113-21. [PMID: 21282087 DOI: 10.1016/j.tcb.2010.10.002] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/04/2010] [Accepted: 10/05/2010] [Indexed: 12/14/2022]
Abstract
Phosphatidylinositol 4-kinases (PI4Ks) regulate vesicle-mediated export from the Golgi apparatus via phosphatidylinositol 4-phosphate (PtdIns4P) binding effector proteins that control vesicle budding reactions and regulate membrane dynamics. Evidence has emerged from the characterization of Golgi PI4K effectors that vesicle budding and lipid dynamics are tightly coupled via a regulatory network that ensures that the appropriate membrane composition is established before a transport vesicle buds from the Golgi. An important hub of this network is protein kinase D, which regulates the activity of PI4K and several PtdIns4P effectors that control sphingolipid and sterol content of Golgi membranes. Other newly identified PtdIns4P effectors include Vps74/GOLPH3, a phospholipid flippase called Drs2 and Sec2, a Rab guanine nucleotide exchange factor (GEF). These effectors orchestrate membrane transformation events facilitating vesicle formation and targeting. In this review, we discuss how PtdIns4P signaling is integrated with membrane biosynthetic and vesicle budding machineries to potentially coordinate these crucial functions of the Golgi apparatus.
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Affiliation(s)
- Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
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42
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Graham TR, Kozlov MM. Interplay of proteins and lipids in generating membrane curvature. Curr Opin Cell Biol 2010; 22:430-6. [PMID: 20605711 DOI: 10.1016/j.ceb.2010.05.002] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/09/2010] [Accepted: 05/03/2010] [Indexed: 01/14/2023]
Abstract
The majority of intracellular membranes have strongly bent shapes with radii of curvature ranging from 20 to 50 nm. Many different proteins provide the substantial energy needed to generate and sustain this curvature. One of the most effective mechanisms of curvature creation is based on asymmetry of membrane monolayers. Proteins generate this asymmetry by flipping phospholipid across the membrane, modifying lipid molecules, or embedding their hydrophobic domains into the membrane matrix. We review the physical principles of these mechanisms of membrane bending and highlight the action of specific proteins driving vesicle-mediated transport. A model of clathrin-mediated vesicle budding from the trans-Golgi network is described to illustrate the interplay and mutual reinforcement of different mechanisms for generating membrane curvature.
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Affiliation(s)
- Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
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Muthusamy BP, Raychaudhuri S, Natarajan P, Abe F, Liu K, Prinz WA, Graham TR. Control of protein and sterol trafficking by antagonistic activities of a type IV P-type ATPase and oxysterol binding protein homologue. Mol Biol Cell 2009; 20:2920-31. [PMID: 19403696 DOI: 10.1091/mbc.e08-10-1036] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The oxysterol binding protein homologue Kes1p has been implicated in nonvesicular sterol transport in Saccharomyces cerevisiae. Kes1p also represses formation of protein transport vesicles from the trans-Golgi network (TGN) through an unknown mechanism. Here, we show that potential phospholipid translocases in the Drs2/Dnf family (type IV P-type ATPases [P4-ATPases]) are downstream targets of Kes1p repression. Disruption of KES1 suppresses the cold-sensitive (cs) growth defect of drs2Delta, which correlates with an enhanced ability of Dnf P4-ATPases to functionally substitute for Drs2p. Loss of Kes1p also suppresses a drs2-ts allele in a strain deficient for Dnf P4-ATPases, suggesting that Kes1p antagonizes Drs2p activity in vivo. Indeed, Drs2-dependent phosphatidylserine translocase (flippase) activity is hyperactive in TGN membranes from kes1Delta cells and is potently attenuated by addition of recombinant Kes1p. Surprisingly, Drs2p also antagonizes Kes1p activity in vivo. Drs2p deficiency causes a markedly increased rate of cholesterol transport from the plasma membrane to the endoplasmic reticulum (ER) and redistribution of endogenous ergosterol to intracellular membranes, phenotypes that are Kes1p dependent. These data suggest a homeostatic feedback mechanism in which appropriately regulated flippase activity in the Golgi complex helps establish a plasma membrane phospholipid organization that resists sterol extraction by a sterol binding protein.
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Zhou X, Graham TR. Purification and characterization of Drs2p, a P4‐ATPase and potential flippase in yeast. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.873.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xiaoming Zhou
- Department of Biological SciencesVanderbilt UniversityNashvilleTN
| | - Todd R. Graham
- Department of Biological SciencesVanderbilt UniversityNashvilleTN
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Muthusamy BP, Natarajan P, Zhou X, Graham TR. Linking phospholipid flippases to vesicle-mediated protein transport. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:612-9. [PMID: 19286470 DOI: 10.1016/j.bbalip.2009.03.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 03/03/2009] [Accepted: 03/04/2009] [Indexed: 11/16/2022]
Abstract
Type IV P-type ATPases (P4-ATPases) are a large family of putative phospholipid translocases (flippases) implicated in the generation of phospholipid asymmetry in biological membranes. P4-ATPases are typically the largest P-type ATPase subgroup found in eukaryotic cells, with five members in Saccharomyces cerevisiae, six members in Caenorhabditis elegans, 12 members in Arabidopsis thaliana and 14 members in humans. In addition, many of the P4-ATPases require interaction with a noncatalytic subunit from the CDC50 gene family for their transport out of the endoplasmic reticulum (ER). Deficiency of a P4-ATPase (Atp8b1) causes liver disease in humans, and studies in a variety of model systems indicate that P4-ATPases play diverse and essential roles in membrane biogenesis. In addition to their proposed role in establishing and maintaining plasma membrane asymmetry, P4-ATPases are linked to vesicle-mediated protein transport in the exocytic and endocytic pathways. Recent studies have also suggested a role for P4-ATPases in the nonvesicular intracellular trafficking of sterols. Here, we discuss the physiological requirements for yeast P4-ATPases in phospholipid translocase activity, transport vesicle budding and ergosterol metabolism, with an emphasis on Drs2p and its noncatalytic subunit, Cdc50p.
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46
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Owens CM, Hamon MD, Graham TR, Wood AJ, Newland AC. Bronchopericardial fistula and pneumopericardium complicating invasive pulmonary aspergillosis. Clin Lab Haematol 2008; 12:351-4. [PMID: 2272163 DOI: 10.1111/j.1365-2257.1990.tb00045.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- C M Owens
- Department of Haematology, London Hospital, Whitechapel, UK
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47
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Liu K, Surendhran K, Nothwehr SF, Graham TR. P4-ATPase requirement for AP-1/clathrin function in protein transport from the trans-Golgi network and early endosomes. Mol Biol Cell 2008; 19:3526-35. [PMID: 18508916 DOI: 10.1091/mbc.e08-01-0025] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Drs2p is a resident type 4 P-type ATPase (P4-ATPase) and potential phospholipid translocase of the trans-Golgi network (TGN) where it has been implicated in clathrin function. However, precise protein transport pathways requiring Drs2p and how it contributes to clathrin-coated vesicle budding remain unclear. Here we show a functional codependence between Drs2p and the AP-1 clathrin adaptor in protein sorting at the TGN and early endosomes of Saccharomyces cerevisiae. Genetic criteria indicate that Drs2p and AP-1 operate in the same pathway and that AP-1 requires Drs2p for function. In addition, we show that loss of AP-1 markedly increases Drs2p trafficking to the plasma membrane, but does not perturb retrieval of Drs2p from the early endosome back to the TGN. Thus AP-1 is required at the TGN to sort Drs2p out of the exocytic pathway, presumably for delivery to the early endosome. Moreover, a conditional allele that inactivates Drs2p phospholipid translocase (flippase) activity disrupts its own transport in this AP-1 pathway. Drs2p physically interacts with AP-1; however, AP-1 and clathrin are both recruited normally to the TGN in drs2Delta cells. These results imply that Drs2p acts independently of coat recruitment to facilitate AP-1/clathrin-coated vesicle budding from the TGN.
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Affiliation(s)
- Ke Liu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA
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48
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Abstract
The proteins of Saccharomyces cervsiae can be metabolically labeled, as described here, with (35)methionine and (35)cysteine or a hydrolysate of E. coli labeled with (35)O4(2-). After the labeling, protocols are provided for the mechanical disruption of the yeast cells or conversion to spheroplasts, with subsequent lysis before immunoprecipitation of the proteins.
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Affiliation(s)
- T R Graham
- Vanderbilt University, Nashville, Tennessee, USA
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49
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Fei W, Alfaro G, Muthusamy BP, Klaassen Z, Graham TR, Yang H, Beh CT. Genome-wide analysis of sterol-lipid storage and trafficking in Saccharomyces cerevisiae. Eukaryot Cell 2008; 7:401-14. [PMID: 18156287 PMCID: PMC2238164 DOI: 10.1128/ec.00386-07] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 12/14/2007] [Indexed: 12/15/2022]
Abstract
The pandemic of lipid-related disease necessitates a determination of how cholesterol and other lipids are transported and stored within cells. The first step in this determination is the identification of the genes involved in these transport and storage processes. Using genome-wide screens, we identified 56 yeast (Saccharomyces cerevisiae) genes involved in sterol-lipid biosynthesis, intracellular trafficking, and/or neutral-lipid storage. Direct biochemical and cytological examination of mutant cells revealed an unanticipated link between secretory protein glycosylation and triacylglycerol (TAG)/steryl ester (SE) synthesis for the storage of lipids. Together with the analysis of other deletion mutants, these results suggested at least two distinct events for the biogenesis of lipid storage particles: a step affecting neutral-lipid synthesis, generating the lipid core of storage particles, and another step for particle assembly. In addition to the lipid storage mutants, we identified mutations that affect the localization of unesterified sterols, which are normally concentrated in the plasma membrane. These findings implicated phospholipase C and the protein phosphatase Ptc1p in the regulation of sterol distribution within cells. This study identified novel sterol-related genes that define several distinct processes maintaining sterol homeostasis.
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Affiliation(s)
- Weihua Fei
- Department of Biochemistry, National University of Singapore, Republic of Singapore
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Abstract
Drs2p family P-type ATPases (P4-ATPases) are required in multiple vesicle-mediated protein transport steps and are proposed to be phospholipid translocases (flippases). The P4-ATPases Drs2p and Dnf1p cycle between the exocytic and endocytic pathways, and here we define endocytosis signals required by these proteins to maintain a steady-state localization to internal organelles. Internalization of Dnf1p from the plasma membrane uses an NPFXD endocytosis signal and its recognition by Sla1p, part of an endocytic coat/adaptor complex with clathrin, Pan1p, Sla2p/End4p, and End3p. Drs2p has multiple endocytosis signals, including two NPFXDs near the C terminus and PEST-like sequences near the N terminus that may mediate ubiquitin (Ub)-dependent endocytosis. Drs2p localizes to the trans-Golgi network in wild-type cells and accumulates on the plasma membrane when both the Ub- and NPFXD-dependent endocytic mechanisms are inactivated. Surprisingly, the pan1-20 temperature-sensitive mutant is constitutively defective for Ub-dependent endocytosis but is not defective for NPFXD-dependent endocytosis at the permissive growth temperature. To sustain viability of pan1-20, Drs2p must be endocytosed through the NPFXD/Sla1p pathway. Thus, Drs2p is an essential endocytic cargo in cells compromised for Ub-dependent endocytosis. These results demonstrate an essential role for endocytosis in retrieving proteins back to the Golgi, and they define critical cargos of the NPFXD/Sla1p system.
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Affiliation(s)
- Ke Liu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
| | - Zhaolin Hua
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
| | - Joshua A. Nepute
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
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