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Plank M, Carmiol N, Mitri B, Lipinski AA, Langlais PR, Capaldi AP. Systems level analysis of time and stimuli specific signaling through PKA. Mol Biol Cell 2024; 35:ar60. [PMID: 38446618 PMCID: PMC11064662 DOI: 10.1091/mbc.e23-02-0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 02/13/2024] [Accepted: 03/01/2024] [Indexed: 03/08/2024] Open
Abstract
It is well known that eukaryotic cells create gradients of cAMP across space and time to regulate the cAMP dependent protein kinase (PKA) and, in turn, growth and metabolism. However, it is unclear how PKA responds to different concentrations of cAMP. Here, to address this question, we examine PKA signaling in Saccharomyces cerevisiae in different conditions, timepoints, and concentrations of the chemical inhibitor 1-NM-PP1, using phosphoproteomics. These experiments show that there are numerous proteins that are only phosphorylated when cAMP and PKA activity are at/near their maximum level, while other proteins are phosphorylated even when cAMP levels and PKA activity are low. The data also show that PKA drives cells into distinct growth states by acting on proteins with different thresholds for phosphorylation in different conditions. Analysis of the sequences surrounding the 118 PKA-dependent phosphosites suggests that the phosphorylation thresholds are set, at least in part, by the affinity of PKA for each site.
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Affiliation(s)
- Michael Plank
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
- The Bio5 Institute, University of Arizona, Tucson, AZ 85721
| | - Nicole Carmiol
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - Bassam Mitri
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | | | - Paul R. Langlais
- The Department of Medicine, University of Arizona, Tucson, AZ 85721
| | - Andrew P. Capaldi
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
- The Bio5 Institute, University of Arizona, Tucson, AZ 85721
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2
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Dibyachintan S, Dube AK, Bradley D, Lemieux P, Dionne U, Landry CR. Cryptic genetic variation shapes the fate of gene duplicates in a protein interaction network. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.23.581840. [PMID: 38464075 PMCID: PMC10925128 DOI: 10.1101/2024.02.23.581840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Paralogous genes are often redundant for long periods of time before they diverge in function. While their functions are preserved, paralogous proteins can accumulate mutations that, through epistasis, could impact their fate in the future. By quantifying the impact of all single-amino acid substitutions on the binding of two myosin proteins to their interaction partners, we find that the future evolution of these proteins is highly contingent on their regulatory divergence and the mutations that have silently accumulated in their protein binding domains. Differences in the promoter strength of the two paralogs amplify the impact of mutations on binding in the lowly expressed one. While some mutations would be sufficient to non-functionalize one paralog, they would have minimal impact on the other. Our results reveal how functionally equivalent protein domains could be destined to specific fates by regulatory and cryptic coding sequence changes that currently have little to no functional impact.
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Affiliation(s)
- Soham Dibyachintan
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
| | - Alexandre K Dube
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
| | - David Bradley
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
| | - Pascale Lemieux
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
| | - Ugo Dionne
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Current affiliation: Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Christian R Landry
- PROTEO-Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
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3
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Lemieux P, Bradley D, Dubé AK, Dionne U, Landry CR. Dissection of the role of a Src homology 3 domain in the evolution of binding preference of paralogous proteins. Genetics 2024; 226:iyad175. [PMID: 37793087 PMCID: PMC10763533 DOI: 10.1093/genetics/iyad175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/07/2023] [Accepted: 08/07/2023] [Indexed: 10/06/2023] Open
Abstract
Protein-protein interactions (PPIs) drive many cellular processes. Some interactions are directed by Src homology 3 (SH3) domains that bind proline-rich motifs on other proteins. The evolution of the binding specificity of SH3 domains is not completely understood, particularly following gene duplication. Paralogous genes accumulate mutations that can modify protein functions and, for SH3 domains, their binding preferences. Here, we examined how the binding of the SH3 domains of 2 paralogous yeast type I myosins, Myo3 and Myo5, evolved following duplication. We found that the paralogs have subtly different SH3-dependent interaction profiles. However, by swapping SH3 domains between the paralogs and characterizing the SH3 domains freed from their protein context, we find that very few of the differences in interactions, if any, depend on the SH3 domains themselves. We used ancestral sequence reconstruction to resurrect the preduplication SH3 domains and examined, moving back in time, how the binding preference changed. Although the most recent ancestor of the 2 domains had a very similar binding preference as the extant ones, older ancestral domains displayed a gradual loss of interaction with the modern interaction partners when inserted in the extant paralogs. Molecular docking and experimental characterization of the free ancestral domains showed that their affinity with the proline motifs is likely not the cause for this loss of binding. Taken together, our results suggest that a SH3 and its host protein could create intramolecular or allosteric interactions essential for the SH3-dependent PPIs, making domains not functionally equivalent even when they have the same binding specificity.
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Affiliation(s)
- Pascale Lemieux
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Regroupement Québécois de Recherche sur la Fonction, l’Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Centre de recherche en données massives (CRDM), Université Laval, 1065, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biochimie, microbiologie et bio-informatique, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
| | - David Bradley
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Regroupement Québécois de Recherche sur la Fonction, l’Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Centre de recherche en données massives (CRDM), Université Laval, 1065, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biochimie, microbiologie et bio-informatique, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
| | - Alexandre K Dubé
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Regroupement Québécois de Recherche sur la Fonction, l’Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Centre de recherche en données massives (CRDM), Université Laval, 1065, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biochimie, microbiologie et bio-informatique, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
| | - Ugo Dionne
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Regroupement Québécois de Recherche sur la Fonction, l’Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Centre de Recherche du Centre Hospitalier Universitaire (CHU) de Québec, Université Laval, Québec, QC, Canada G1R 2J6
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada M5G 1X5
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Regroupement Québécois de Recherche sur la Fonction, l’Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Centre de recherche en données massives (CRDM), Université Laval, 1065, Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biochimie, microbiologie et bio-informatique, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
- Département de biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, Canada G1V 0A6
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4
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Hummel DR, Kaksonen M. Spatio-temporal regulation of endocytic protein assembly by SH3 domains in yeast. Mol Biol Cell 2023; 34:ar19. [PMID: 36696224 PMCID: PMC10011730 DOI: 10.1091/mbc.e22-09-0406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Clathrin-mediated endocytosis is a conserved eukaryotic membrane trafficking pathway that is driven by a sequentially assembled molecular machinery that contains over 60 different proteins. SH3 domains are the most abundant protein-protein interaction domain in this process, but the function of most SH3 domains in protein dynamics remains elusive. Using mutagenesis and live-cell fluorescence microscopy in the budding yeast Saccharomyces cerevisiae, we dissected SH3-mediated regulation of the endocytic pathway. Our data suggest that multiple SH3 domains regulate the actin nucleation-promoting Las17-Vrp1 complex, and that the network of SH3 interactions coordinates both Las17-Vrp1 assembly and dissociation. Furthermore, most endocytic SH3 domain proteins use the SH3 domain for their own recruitment, while a minority use the SH3 domain to recruit other proteins and not themselves. Our results provide a dynamic map of SH3 functions in yeast endocytosis and a framework for SH3 interaction network studies across biology.
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Affiliation(s)
- Daniel R Hummel
- Department of Biochemistry, University of Geneva, Department of Biochemistry, 1205 Genève, Switzerland
| | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, Department of Biochemistry, 1205 Genève, Switzerland
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5
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Aimvijarn P, Payuhakrit W, Charoenchon N, Okada S, Suwannalert P. Riceberry Rice Germination and UVB Radiation Enhance Protocatechuic Acid and Vanillic Acid to Reduce Cellular Oxidative Stress and Suppress B16F10 Melanogenesis Relating to F-Actin Rearrangement. PLANTS (BASEL, SWITZERLAND) 2023; 12:484. [PMID: 36771569 PMCID: PMC9920603 DOI: 10.3390/plants12030484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/12/2023] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Ultraviolet type B (UVB) radiation plays an important role in hyperpigmentation disorder, which induces cellular oxidative stress and causes abnormal melanin production and secretion. The stress condition plays an essential role in actin polymerization relating to F-actin rearrangement and forms dendrite to send melanin pigment to the uppermost layer of the skin. Phenolic compounds are secondary metabolites that mainly synthesize under stress conditions to protect plants from harmful environments and have been reported as effective agents in anti-oxidant and anti-melanogenesis. However, the influence of phenolic compounds on F-actin rearrangement-associated dendrite formation has not been studied so far. Hence, this study aimed to investigate the enhancing phytophenolic targets in riceberry rice (Oryza sativa L.) germination and UVB radiation (RR-GR) to suppress melanogenesis relating to F-rearrangement. As a result, the RR-GR had the potential to enhance phenolic acids such as protocatechuic and vanillic acid, which have been proven to possess anti-oxidant activity and anti-tyrosinase properties. Riceberry rice's modification showed the potential to reduce cellular oxidative stress and suppress B16F10 melanogenesis relating to F-actin rearrangement that is associated with dendrite formation.
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Affiliation(s)
- Parichaya Aimvijarn
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Witchuda Payuhakrit
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Pathobiology Information and Learning Center, Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Nisamanee Charoenchon
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Seiji Okada
- Division of Hematopoiesis, Joint Research Center for Human Retrovirus Infection, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan
| | - Prasit Suwannalert
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Pathobiology Information and Learning Center, Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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6
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MacQuarrie CD, Mangione MC, Carroll R, James M, Gould KL, Sirotkin V. The S. pombe adaptor protein Bbc1 regulates localization of Wsp1 and Vrp1 during endocytic actin patch assembly. J Cell Sci 2019; 132:jcs233502. [PMID: 31391237 PMCID: PMC6771142 DOI: 10.1242/jcs.233502] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/24/2019] [Indexed: 01/01/2023] Open
Abstract
Arp2/3 complex-nucleated branched actin networks provide the key force necessary for endocytosis. The Arp2/3 complex is activated by nucleation-promoting factors including the Schizosaccharomyces pombe Wiskott-Aldrich syndrome protein (Wsp1) and myosin-1 (Myo1). There are >40 known yeast endocytic proteins with distinct spatial and temporal localizations and functions; however, it is still unclear how these proteins work together to drive endocytosis. Here, we used quantitative live-cell imaging to determine the function of the uncharacterized S. pombe protein Bbc1. We discovered that Myo1 interacts with and recruits Bbc1 to sites of endocytosis. Bbc1 competes with the verprolin Vrp1 for localization to patches and association with Myo1, thus releasing Vrp1 and its binding partner Wsp1 from Myo1. Normally Myo1 remains at the base of the endocytic invagination and Vrp1-Wsp1 internalizes with the endocytic vesicle. However, in the absence of Bbc1, a portion of Vrp1-Wsp1 remains with Myo1 at the base of the invagination, and endocytic structures internalize twice as far. We propose that Bbc1 disrupts a transient interaction of Myo1 with Vrp1 and Wsp1 and thereby limits Arp2/3 complex-mediated nucleation of actin branches at the plasma membrane.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Cameron Dale MacQuarrie
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - MariaSanta C Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert Carroll
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Michael James
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Vladimir Sirotkin
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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7
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Manenschijn HE, Picco A, Mund M, Rivier-Cordey AS, Ries J, Kaksonen M. Type-I myosins promote actin polymerization to drive membrane bending in endocytosis. eLife 2019; 8:44215. [PMID: 31385806 PMCID: PMC6684269 DOI: 10.7554/elife.44215] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/23/2019] [Indexed: 12/24/2022] Open
Abstract
Clathrin-mediated endocytosis in budding yeast requires the formation of a dynamic actin network that produces the force to invaginate the plasma membrane against the intracellular turgor pressure. The type-I myosins Myo3 and Myo5 are important for endocytic membrane reshaping, but mechanistic details of their function remain scarce. Here, we studied the function of Myo3 and Myo5 during endocytosis using quantitative live-cell imaging and genetic perturbations. We show that the type-I myosins promote, in a dose-dependent way, the growth and expansion of the actin network, which controls the speed of membrane and coat internalization. We found that this myosin-activity is independent of the actin nucleation promoting activity of myosins, and cannot be compensated for by increasing actin nucleation. Our results suggest a new mechanism for type-I myosins to produce force by promoting actin filament polymerization.
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Affiliation(s)
- Hetty E Manenschijn
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andrea Picco
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Markus Mund
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Jonas Ries
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
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8
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Sidhu N, Dawson JF. A crosslinked and ribosylated actin trimer does not interact productively with myosin. Biochem Cell Biol 2019; 97:140-147. [DOI: 10.1139/bcb-2018-0082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A purified F-actin-derived actin trimer that interacts with end-binding proteins did not activate or bind the side-binding protein myosin under rigor conditions. Remodeling of the actin trimer by the binding of gelsolin did not rescue myosin binding, nor did the use of different means of inhibiting the polymerization of the trimer. Our results demonstrate that ADP-ribosylation on all actin subunits of an F-actin-derived trimer inhibits myosin binding and that the binding of DNase-I to the pointed end subunits of a crosslinked trimer also remodels the myosin binding site. Taken together, this work highlights the need for a careful balance between modification of actin subunits and maintaining protein–protein interactions to produce a physiologically relevant short F-actin complex.
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Affiliation(s)
- Navneet Sidhu
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - John F. Dawson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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9
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Xu Q, Huff LP, Fujii M, Griendling KK. Redox regulation of the actin cytoskeleton and its role in the vascular system. Free Radic Biol Med 2017; 109:84-107. [PMID: 28285002 PMCID: PMC5497502 DOI: 10.1016/j.freeradbiomed.2017.03.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/17/2017] [Accepted: 03/06/2017] [Indexed: 12/17/2022]
Abstract
The actin cytoskeleton is critical for form and function of vascular cells, serving mechanical, organizational and signaling roles. Because many cytoskeletal proteins are sensitive to reactive oxygen species, redox regulation has emerged as a pivotal modulator of the actin cytoskeleton and its associated proteins. Here, we summarize work implicating oxidants in altering actin cytoskeletal proteins and focus on how these alterations affect cell migration, proliferation and contraction of vascular cells. Finally, we discuss the role of oxidative modification of the actin cytoskeleton in vivo and highlight its importance for vascular diseases.
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Affiliation(s)
- Qian Xu
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308a WMB, Atlanta, GA 30322, United States; Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Lauren P Huff
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308a WMB, Atlanta, GA 30322, United States
| | - Masakazu Fujii
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Japan
| | - Kathy K Griendling
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308a WMB, Atlanta, GA 30322, United States.
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10
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Whitworth K, Bradford MK, Camara N, Wendland B. Targeted disruption of an EH-domain protein endocytic complex, Pan1-End3. Traffic 2013; 15:43-59. [PMID: 24118836 DOI: 10.1111/tra.12125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/23/2013] [Accepted: 09/30/2013] [Indexed: 02/04/2023]
Abstract
Pan1 is a multi-domain scaffold that enables dynamic interactions with both structural and regulatory components of the endocytic pathway. Pan1 is composed of Eps15 Homology (EH) domains which interact with adaptor proteins, a central region that is responsible for its oligomerization and C-terminal binding sites for Arp2/3, F-actin, and type-I myosin motors. In this study, we have characterized the binding sites between Pan1 and its constitutive binding partner End3, another EH domain containing endocytic protein. The C-terminal End3 Repeats of End3 associate with the N-terminal part of Pan1's central coiled-coil region. These repeats appear to act independently of one another as tandem, redundant binding sites for Pan1. The end3-1 allele was sequenced, and corresponds to a C-terminal truncation lacking the End3 Repeats. Mutations of the End3 Repeats highlight that those residues which are identical between these repeats serve as contact sites for the interaction with Pan1.
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Affiliation(s)
- Karen Whitworth
- Department of Biology, The Johns Hopkins University, Baltimore, MD, 21218, USA
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11
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Knabe N, Jung EM, Freihorst D, Hennicke F, Horton JS, Kothe E. A central role for Ras1 in morphogenesis of the basidiomycete Schizophyllum commune. EUKARYOTIC CELL 2013; 12:941-52. [PMID: 23606288 PMCID: PMC3675993 DOI: 10.1128/ec.00355-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/17/2013] [Indexed: 11/20/2022]
Abstract
Fungi have been used as model systems to define general processes in eukaryotes, for example, the one gene-one enzyme hypothesis, as well as to study polar growth or pathogenesis. Here, we show a central role for the regulator protein Ras in a mushroom-forming, filamentous basidiomycete linking growth, pheromone signaling, sexual development, and meiosis to different signal transduction pathways. ras1 and Ras-specific gap1 mutants were generated and used to modify the intracellular activation state of the Ras module. Transformants containing constitutive ras1 alleles (ras1(G12V) and ras1(Q61L)), as well as their compatible mating interactions, did show strong phenotypes for growth (associated with Cdc42 signaling) and mating (associated with mitogen-activated protein kinase signaling). Normal fruiting bodies with abnormal spores exhibiting a reduced germination rate were produced by outcrossing of these mutant strains. Homozygous Δgap1 primordia, expected to experience increased Ras signaling, showed overlapping phenotypes with a block in basidium development and meiosis. Investigation of cyclic AMP (cAMP)-dependent protein kinase A indicated that constitutively active ras1, as well as Δgap1 mutant strains, exhibit a strong increase in Tpk activity. Ras1-dependent, cAMP-mediated signal transduction is, in addition to the known signaling pathways, involved in fruiting body formation in Schizophyllum commune. To integrate these analyses of Ras signaling, microarray studies were performed. Mutant strains containing constitutively active Ras1, deletion of RasGap1, or constitutively active Cdc42 were characterized and compared. At the transcriptome level, specific regulation highlighting the phenotypic differences of the mutants is clearly visible.
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Affiliation(s)
- Nicole Knabe
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Elke-Martina Jung
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Daniela Freihorst
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Florian Hennicke
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Junior Research Group Fundamental Molecular Biology of Pathogenic Fungi, Jena, Germany
| | - J. Stephen Horton
- Department of Biological Sciences, Science and Engineering Center, Union College, Schenectady, New York, USA
| | - Erika Kothe
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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12
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Hachiro T, Yamamoto T, Nakano K, Tanaka K. Phospholipid flippases Lem3p-Dnf1p and Lem3p-Dnf2p are involved in the sorting of the tryptophan permease Tat2p in yeast. J Biol Chem 2012; 288:3594-608. [PMID: 23250744 DOI: 10.1074/jbc.m112.416263] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The type 4 P-type ATPases are flippases that generate phospholipid asymmetry in membranes. In budding yeast, heteromeric flippases, including Lem3p-Dnf1p and Lem3p-Dnf2p, translocate phospholipids to the cytoplasmic leaflet of membranes. Here, we report that Lem3p-Dnf1/2p are involved in transport of the tryptophan permease Tat2p to the plasma membrane. The lem3Δ mutant exhibited a tryptophan requirement due to the mislocalization of Tat2p to intracellular membranes. Tat2p was relocalized to the plasma membrane when trans-Golgi network (TGN)-to-endosome transport was inhibited. Inhibition of ubiquitination by mutations in ubiquitination machinery also rerouted Tat2p to the plasma membrane. Lem3p-Dnf1/2p are localized to endosomal/TGN membranes in addition to the plasma membrane. Endocytosis mutants, in which Lem3p-Dnf1/2p are sequestered to the plasma membrane, also exhibited the ubiquitination-dependent missorting of Tat2p. These results suggest that Tat2p is ubiquitinated at the TGN and missorted to the vacuolar pathway in the lem3Δ mutant. The NH(2)-terminal cytoplasmic region of Tat2p containing ubiquitination acceptor lysines interacted with liposomes containing acidic phospholipids, including phosphatidylserine. This interaction was abrogated by alanine substitution mutations in the basic amino acids downstream of the ubiquitination sites. Interestingly, a mutant Tat2p containing these substitutions was missorted in a ubiquitination-dependent manner. We propose the following model based on these results; Tat2p is not ubiquitinated when the NH(2)-terminal region is bound to membrane phospholipids, but if it dissociates from the membrane due to a low level of phosphatidylserine caused by perturbation of phospholipid asymmetry in the lem3Δ mutant, Tat2p is ubiquitinated and then transported from the TGN to the vacuole.
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Affiliation(s)
- Takeru Hachiro
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, N15 W7, Kita-ku, Sapporo 060-0815, Japan
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13
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Proteomic analysis of the increased stress tolerance of saccharomyces cerevisiae encapsulated in liquid core alginate-chitosan capsules. PLoS One 2012; 7:e49335. [PMID: 23152898 PMCID: PMC3494678 DOI: 10.1371/journal.pone.0049335] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 10/10/2012] [Indexed: 11/19/2022] Open
Abstract
Saccharomyces cerevisiae CBS8066 encapsulated in semi-permeable alginate or alginate-chitosan liquid core capsules have been shown to have an enhanced tolerance towards complex dilute-acid lignocellulose hydrolysates and the lignocellulose-derived inhibitor furfural, as well as towards high temperatures. The underlying molecular reasons for these effects have however not been elucidated. In this study we have investigated the response of the encapsulation on the proteome level in the yeast cells, in comparison with cells grown freely in suspension under otherwise similar conditions. The proteomic analysis was performed on whole cell protein extracts using nLC-MS/MS with TMT® labelling and 2-D DIGE. 842 and 52 proteins were identified using each method, respectively. The abundances of 213 proteins were significantly different between encapsulated and suspended cells, with good correlation between the fold change ratios obtained by the two methods for proteins identified in both. Encapsulation of the yeast caused an up-regulation of glucose-repressed proteins and of both general and starvation-specific stress responses, such as the trehalose biosynthesis pathway, and down-regulation of proteins linked to growth and protein synthesis. The encapsulation leads to a lack of nutrients for cells close to the core of the capsule due to mass transfer limitations. The triggering of the stress response may be beneficial for the cells in certain conditions, for example leading to the increased tolerance towards high temperatures and certain inhibitors.
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14
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Casolari JM, Thompson MA, Salzman J, Champion LM, Moerner WE, Brown PO. Widespread mRNA association with cytoskeletal motor proteins and identification and dynamics of myosin-associated mRNAs in S. cerevisiae. PLoS One 2012; 7:e31912. [PMID: 22359641 PMCID: PMC3281097 DOI: 10.1371/journal.pone.0031912] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 01/15/2012] [Indexed: 01/08/2023] Open
Abstract
Programmed mRNA localization to specific subcellular compartments for localized translation is a fundamental mechanism of post-transcriptional regulation that affects many, and possibly all, mRNAs in eukaryotes. We describe here a systematic approach to identify the RNA cargoes associated with the cytoskeletal motor proteins of Saccharomyces cerevisiae in combination with live-cell 3D super-localization microscopy of endogenously tagged mRNAs. Our analysis identified widespread association of mRNAs with cytoskeletal motor proteins, including association of Myo3 with mRNAs encoding key regulators of actin branching and endocytosis such as WASP and WIP. Using conventional fluorescence microscopy and expression of MS2-tagged mRNAs from endogenous loci, we observed a strong bias for actin patch nucleator mRNAs to localize to the cell cortex and the actin patch in a Myo3- and F-actin dependent manner. Use of a double-helix point spread function (DH-PSF) microscope allowed super-localization measurements of single mRNPs at a spatial precision of 25 nm in x and y and 50 nm in z in live cells with 50 ms exposure times, allowing quantitative profiling of mRNP dynamics. The actin patch mRNA exhibited distinct and characteristic diffusion coefficients when compared to a control mRNA. In addition, disruption of F-actin significantly expanded the 3D confinement radius of an actin patch nucleator mRNA, providing a quantitative assessment of the contribution of the actin cytoskeleton to mRNP dynamic localization. Our results provide evidence for specific association of mRNAs with cytoskeletal motor proteins in yeast, suggest that different mRNPs have distinct and characteristic dynamics, and lend insight into the mechanism of actin patch nucleator mRNA localization to actin patches.
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Affiliation(s)
- Jason M. Casolari
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael A. Thompson
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - Julia Salzman
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Statistics, Stanford University, Stanford, California, United States of America
| | - Lowry M. Champion
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - W. E. Moerner
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - Patrick O. Brown
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
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15
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Wang P, Shen G. The endocytic adaptor proteins of pathogenic fungi: charting new and familiar pathways. Med Mycol 2011; 49:449-57. [PMID: 21254965 DOI: 10.3109/13693786.2011.553246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Intracellular transport is an essential biological process that is highly conserved throughout the eukaryotic organisms. In fungi, adaptor proteins implicated in the endocytic cycle of endocytosis and exocytosis were found to be important for growth, differentiation, and/or virulence. For example, Saccharomyces cerevisiae Pan1 is an endocytic protein that regulates membrane trafficking, the actin cytoskeleton, and signaling. In Cryptococcus neoformans, a multi-modular endocytic protein, Cin1, was recently found to have pleiotropic functions in morphogenesis, endocytosis, exocytosis, and virulence. Interestingly, Cin1 is homologous to human intersectin ITSN1, but homologs of Cin1/ITSN1 were not found in ascomycetous S. cerevisiae and Candida albicans, or zygomycetous fungi. Moreover, an Eps15 protein homologous to S. cerevisiae Pan1/Ede1 and additional relevant protein homologs were identified in C. neoformans, suggesting the existence of either a distinct endocytic pathway mediated by Cin1 or pathways by either Cin1 or/and Pan1/Ede1 homologs. Whether and how the Cin1-mediated endocytic pathway represents a unique role in pathogenesis or reflects a redundancy of a transport apparatus remains an open and challenging question. This review discusses recent findings of endocytic adaptor proteins from pathogenic fungi and provides a perspective for novel endocytic machinery operating in C. neoformans. An understanding of intracellular trafficking mechanisms as they relate to pathogenesis will likely reveal the identity of novel antifungal targets.
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Affiliation(s)
- Ping Wang
- The Research Institute for Children, New Orleans, Louisiana, USA.
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16
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Yamamoto T, Mochida J, Kadota J, Takeda M, Bi E, Tanaka K. Initial polarized bud growth by endocytic recycling in the absence of actin cable-dependent vesicle transport in yeast. Mol Biol Cell 2010; 21:1237-52. [PMID: 20147449 PMCID: PMC2847527 DOI: 10.1091/mbc.e09-05-0412] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Budding yeast mutants in assembly of actin cables, which are thought to be the only actin structures essential for budding, still could form a small bud. Mutations in actin patch endocytic machineries/endocytic recycling factors inhibited this budding, suggesting a mechanism that promotes polarized growth by local recycling of endocytic vesicles. The assembly of filamentous actin is essential for polarized bud growth in budding yeast. Actin cables, which are assembled by the formins Bni1p and Bnr1p, are thought to be the only actin structures that are essential for budding. However, we found that formin or tropomyosin mutants, which lack actin cables, are still able to form a small bud. Additional mutations in components for cortical actin patches, which are assembled by the Arp2/3 complex to play a pivotal role in endocytic vesicle formation, inhibited this budding. Genes involved in endocytic recycling were also required for small-bud formation in actin cable-less mutants. These results suggest that budding yeast possesses a mechanism that promotes polarized growth by local recycling of endocytic vesicles. Interestingly, the type V myosin Myo2p, which was thought to use only actin cables to track, also contributed to budding in the absence of actin cables. These results suggest that some actin network may serve as the track for Myo2p-driven vesicle transport in the absence of actin cables or that Myo2p can function independent of actin filaments. Our results also show that polarity regulators including Cdc42p were still polarized in mutants defective in both actin cables and cortical actin patches, suggesting that the actin cytoskeleton does not play a major role in cortical assembly of polarity regulators in budding yeast.
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Affiliation(s)
- Takaharu Yamamoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
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17
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Boettner DR, D'Agostino JL, Torres OT, Daugherty-Clarke K, Uygur A, Reider A, Wendland B, Lemmon SK, Goode BL. The F-BAR protein Syp1 negatively regulates WASp-Arp2/3 complex activity during endocytic patch formation. Curr Biol 2009; 19:1979-87. [PMID: 19962315 DOI: 10.1016/j.cub.2009.10.062] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/11/2009] [Accepted: 10/16/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND Actin polymerization by Arp2/3 complex must be tightly regulated to promote clathrin-mediated endocytosis. Although many Arp2/3 complex activators have been identified, mechanisms for its negative regulation have remained more elusive. To address this, we analyzed the yeast arp2-7 allele, which is biochemically unique in causing unregulated actin assembly in vitro in the absence of Arp2/3 activators. RESULTS We examined endocytosis in arp2-7 mutants by live-cell imaging of Sla1-GFP, a coat marker, and Abp1-RFP, which marks the later actin phase of endocytosis. Sla1-GFP and Abp1-RFP lifetimes were accelerated in arp2-7 mutants, which is opposite to actin nucleation-impaired arp2 alleles or deletions of Arp2/3 activators. We performed a screen for multicopy suppressors of arp2-7 and identified SYP1, an FCHO1 homolog, which contains F-BAR and AP-2micro homology domains. Overexpression of SYP1 in arp2-7 cells slowed Sla1-GFP lifetimes closer to wild-type cells. Further, purified Syp1 directly inhibited Las17/WASp stimulation of Arp2/3 complex-mediated actin assembly in vitro. This activity was mapped to a fragment of Syp1 located between its F-BAR and AP-2micro homology domains and depends on sequences in Las17/WASp outside of the VCA domain. CONCLUSIONS Together, these data identify Syp1 as a novel negative regulator of WASp-Arp2/3 complex that helps choreograph the precise timing of actin assembly during endocytosis.
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Affiliation(s)
- Douglas R Boettner
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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18
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Idrissi FZ, Grötsch H, Fernández-Golbano IM, Presciatto-Baschong C, Riezman H, Geli MI. Distinct acto/myosin-I structures associate with endocytic profiles at the plasma membrane. J Cell Biol 2008; 180:1219-32. [PMID: 18347067 PMCID: PMC2290847 DOI: 10.1083/jcb.200708060] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Accepted: 02/13/2008] [Indexed: 11/24/2022] Open
Abstract
Endocytosis in yeast requires actin and clathrin. Live cell imaging has previously shown that massive actin polymerization occurs concomitant with a slow 200-nm inward movement of the endocytic coat (Kaksonen, M., Y. Sun, and D.G. Drubin. 2003. Cell. 115:475-487). However, the nature of the primary endocytic profile in yeast and how clathrin and actin cooperate to generate an endocytic vesicle is unknown. In this study, we analyze the distribution of nine different proteins involved in endocytic uptake along plasma membrane invaginations using immunoelectron microscopy. We find that the primary endocytic profiles are tubular invaginations of up to 50 nm in diameter and 180 nm in length, which accumulate the endocytic coat components at the tip. Interestingly, significant actin labeling is only observed on invaginations longer than 50 nm, suggesting that initial membrane bending occurs before initiation of the slow inward movement. We also find that in the longest profiles, actin and the myosin-I Myo5p form two distinct structures that might be implicated in vesicle fission.
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Affiliation(s)
- Fatima-Zahra Idrissi
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028 Barcelona, Spain
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19
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Park HO, Bi E. Central roles of small GTPases in the development of cell polarity in yeast and beyond. Microbiol Mol Biol Rev 2007; 71:48-96. [PMID: 17347519 PMCID: PMC1847380 DOI: 10.1128/mmbr.00028-06] [Citation(s) in RCA: 323] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
SUMMARY The establishment of cell polarity is critical for the development of many organisms and for the function of many cell types. A large number of studies of diverse organisms from yeast to humans indicate that the conserved, small-molecular-weight GTPases function as key signaling proteins involved in cell polarization. The budding yeast Saccharomyces cerevisiae is a particularly attractive model because it displays pronounced cell polarity in response to intracellular and extracellular cues. Cells of S. cerevisiae undergo polarized growth during various phases of their life cycle, such as during vegetative growth, mating between haploid cells of opposite mating types, and filamentous growth upon deprivation of nutrition such as nitrogen. Substantial progress has been made in deciphering the molecular basis of cell polarity in budding yeast. In particular, it becomes increasingly clear how small GTPases regulate polarized cytoskeletal organization, cell wall assembly, and exocytosis at the molecular level and how these GTPases are regulated. In this review, we discuss the key signaling pathways that regulate cell polarization during the mitotic cell cycle and during mating.
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Affiliation(s)
- Hay-Oak Park
- Department of Molecular Genetics, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210-1292, USA.
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20
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Abstract
Increasing evidence from a variety of cell types has highlighted the importance of the actin cytoskeleton during endocytosis. No longer is actin viewed as a passive barrier that must be removed to allow endocytosis to proceed. Rather, actin structures are dynamically organised to assist the remodelling of the cell surface to allow inward movement of vesicles. The majority of our mechanistic insight into the role of actin in endocytosis has come from studies in budding yeast. Although endocytosis in mammalian cells is clearly more complex and subject to a greater array of regulatory signals, recent advances have revealed actin, and actin-regulatory proteins, to be present at endocytic sites. Furthermore, live cell imaging indicates that spatiotemporal aspects of actin recruitment and vesicle formation are likely to be conserved across eukaryotic evolution.
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Affiliation(s)
- Elizabeth Smythe
- Department of Biomedical Science, Firth Court, Western Bank, University of Sheffield, Sheffield, UK
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21
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Takahashi T, Furuchi T, Naganuma A. Endocytic Ark/Prk kinases play a critical role in adriamycin resistance in both yeast and mammalian cells. Cancer Res 2007; 66:11932-7. [PMID: 17178891 DOI: 10.1158/0008-5472.can-06-3220] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To elucidate the mechanism of acquired resistance to Adriamycin, we searched for genes that, when overexpressed, render Saccharomyces cerevisiae resistant to Adriamycin. We identified AKL1, a gene of which the function is unknown but is considered, nonetheless, to be a member of the Ark/Prk kinase family, which is involved in the regulation of endocytosis, on the basis of its deduced amino acid sequence. Among tested members of the Ark/Prk kinase family (Ark1, Prk1, and Akl1), overexpressed Prk1 also conferred Adriamycin resistance on yeast cells. Prk1 is known to dissociate the Sla1/Pan1/End3 complex, which is involved in endocytosis, by phosphorylating Sla1 and Pan1 in the complex. We showed that Akl1 promotes phosphorylation of Pan1 in this complex and reduces the endocytic ability of the cell, as does Prk1. Sla1- and End3-defective yeast cells were also resistant to Adriamycin and overexpression of Akl1 in these defective cells did not increase the degree of Adriamycin resistance, suggesting that Akl1 might reduce Adriamycin toxicity by reducing the endocytic ability of cells via a mechanism that involves the Sla1/Pan1/End3 complex and the phosphorylation of Pan1. We also found that HEK293 cells that overexpressed AAK1, a member of the human Ark/Prk family, were Adriamycin resistant. Our findings suggest that endocytosis might be involved in the mechanism of Adriamycin toxicity in yeast and human cells.
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Affiliation(s)
- Tsutomu Takahashi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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22
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Lanzardo S, Curcio C, Forni G, Antón IM. A role for WASP Interacting Protein, WIP, in fibroblast adhesion, spreading and migration. Int J Biochem Cell Biol 2006; 39:262-74. [PMID: 17008118 DOI: 10.1016/j.biocel.2006.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 08/10/2006] [Accepted: 08/12/2006] [Indexed: 01/21/2023]
Abstract
The WASP (Wiskott Aldrich Syndrome Protein) Interacting Protein, WIP, regulates actin polymerization and the formation of actin-rich structures such as filopodia and lamellipodia, each of which is involved in cellular adhesion, spreading and migration. To define the role for WIP in these activities, we analysed cell adhesion and spreading as well as the redistribution of polymerised actin and paxillin that occurred when fibroblasts were plated onto different substrata. We compared the effect of WIP overexpression (gain of function) with that of WIP deficiency (loss of function) on these parameters. WIP-overexpression delayed cellular adhesion and spreading, an effect that could be compensated for by exposure to Y-27632, a well characterized ROCK (Rho kinase) inhibitor. WIP overexpression augmented the phosphorylation of Erk and JNK induced by binding to fibronectin, suggesting that WIP participates in signal transduction pathways initiated by integrin engagement. Conversely, WIP deficiency accelerated fibroblast adhesion to plastic and led to the formation of enlarged focal adhesions. The influence of WIP on fibroblast migration was measured by scratch assay. WIP-overexpression reduced migration while WIP-deficiency increased it, suggesting that WIP acts as a negative regulator of fibroblast migration. Together, these findings suggest a novel role for WIP in fibroblast adhesion, spreading and migration.
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23
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Sun Y, Martin AC, Drubin DG. Endocytic internalization in budding yeast requires coordinated actin nucleation and myosin motor activity. Dev Cell 2006; 11:33-46. [PMID: 16824951 DOI: 10.1016/j.devcel.2006.05.008] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 05/03/2006] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
Actin polymerization essential for endocytic internalization in budding yeast is controlled by four nucleation promoting factors (NPFs) that each exhibits a unique dynamic behavior at endocytic sites. How each NPF functions and is regulated to restrict actin assembly to late stages of endocytic internalization is not known. Quantitative analysis of NPF biochemical activities, and genetic analysis of recruitment and regulatory mechanisms, defined a linear pathway in which protein composition changes at endocytic sites control actin assembly and function. We show that yeast WASP initiates actin assembly at endocytic sites and that this assembly and the recruitment of a yeast WIP-like protein by WASP recruit a type I myosin with both NPF and motor activities. Importantly, type I myosin motor and NPF activities are separable, and both contribute to endocytic coat inward movement, which likely represents membrane invagination. These results reveal a mechanism in which actin nucleation and myosin motor activity cooperate to promote endocytic internalization.
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Affiliation(s)
- Yidi Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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24
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Musi V, Birdsall B, Fernandez-Ballester G, Guerrini R, Salvatori S, Serrano L, Pastore A. New approaches to high-throughput structure characterization of SH3 complexes: the example of Myosin-3 and Myosin-5 SH3 domains from S. cerevisiae. Protein Sci 2006; 15:795-807. [PMID: 16600966 PMCID: PMC2242487 DOI: 10.1110/ps.051785506] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
SH3 domains are small protein modules that are involved in protein-protein interactions in several essential metabolic pathways. The availability of the complete genome and the limited number of clearly identifiable SH3 domains make the yeast Saccharomyces cerevisae an ideal proteomic-based model system to investigate the structural rules dictating the SH3-mediated protein interactions and to develop new tools to assist these studies. In the present work, we have determined the solution structure of the SH3 domain from Myo3 and modeled by homology that of the highly homologous Myo5, two myosins implicated in actin polymerization. We have then implemented an integrated approach that makes use of experimental and computational methods to characterize their binding properties. While accommodating their targets in the classical groove, the two domains have selectivity in both orientation and sequence specificity of the target peptides. From our study, we propose a consensus sequence that may provide a useful guideline to identify new natural partners and suggest a strategy of more general applicability that may be of use in other structural proteomic studies.
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Affiliation(s)
- Valeria Musi
- National Institute for Medical Research, London NW71AA, United Kingdom
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25
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Yoshiuchi S, Yamamoto T, Sakane H, Kadota J, Mochida J, Asaka M, Tanaka K. Identification of novel mutations in ACT1 and SLA2 that suppress the actin-cable-overproducing phenotype caused by overexpression of a dominant active form of Bni1p in Saccharomyces cerevisiae. Genetics 2006; 173:527-39. [PMID: 16547104 PMCID: PMC1526543 DOI: 10.1534/genetics.105.055210] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A formin Bni1p nucleates actin to assemble actin cables, which guide the polarized transport of secretory vesicles in budding yeast. We identified mutations that suppressed both the lethality and the excessive actin cable formation caused by overexpression of a truncated Bni1p (BNI1DeltaN). Two recessive mutations, act1-301 in the actin gene and sla2-82 in a gene involved in cortical actin patch assembly, were identified. The isolation of sla2-82 was unexpected, because cortical actin patches are required for the internalization step of endocytosis. Both act1-301 and sla2-82 exhibited synthetic growth defects with bni1Delta. act1-301, which resulted in an E117K substitution, interacted genetically with mutations in profilin (PFY1) and BUD6, suggesting that Act1-301p was not fully functional in formin-mediated polymerization. sla2-82 also interacted genetically with genes involved in actin cable assembly. Some experiments, however, suggested that the effects of sla2-82 were caused by depletion of actin monomers, because the temperature-sensitive growth phenotype of the bni1Delta sla2-82 mutant was suppressed by increased expression of ACT1. The isolation of suppressors of the BNI1DeltaN phenotype may provide a useful system for identification of actin amino-acid residues that are important for formin-mediated actin polymerization and mutations that affect the availability of actin monomers.
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Affiliation(s)
- Shiro Yoshiuchi
- Division of Molecular Interaction, Institute of Genetic Medicine, Hokkaido University Graduate School of Medicine, Sapporo 060-0815, Japan
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26
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Kishimoto T, Yamamoto T, Tanaka K. Defects in structural integrity of ergosterol and the Cdc50p-Drs2p putative phospholipid translocase cause accumulation of endocytic membranes, onto which actin patches are assembled in yeast. Mol Biol Cell 2005; 16:5592-609. [PMID: 16195350 PMCID: PMC1289405 DOI: 10.1091/mbc.e05-05-0452] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 08/24/2005] [Accepted: 09/15/2005] [Indexed: 11/11/2022] Open
Abstract
Specific changes in membrane lipid composition are implicated in actin cytoskeletal organization, vesicle formation, and control of cell polarity. Cdc50p, a membrane protein in the endosomal/trans-Golgi network compartments, is a noncatalytic subunit of Drs2p, which is implicated in translocation of phospholipids across lipid bilayers. We found that the cdc50Delta mutation is synthetically lethal with mutations affecting the late steps of ergosterol synthesis (erg2 to erg6). Defects in cell polarity and actin organization were observed in the cdc50Delta erg3Delta mutant. In particular, actin patches, which are normally found at cortical sites, were assembled intracellularly along with their assembly factors, including Las17p, Abp1p, and Sla2p. The exocytic SNARE Snc1p, which is recycled by an endocytic route, was also intracellularly accumulated, and inhibition of endocytic internalization suppressed the cytoplasmic accumulation of both Las17p and Snc1p. Simultaneous loss of both phospholipid asymmetry and sterol structural integrity could lead to accumulation of endocytic intermediates capable of initiating assembly of actin patches in the cytoplasm.
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Affiliation(s)
- Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-0815, Japan
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27
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Abstract
SH3 (Src homology-3) domains are involved in protein-protein interactions through proline-rich domains. Many SH3-containing proteins are implicated in actin cytoskeleton organization. The aim of our ongoing work is to study the functions of the SH3-containing proteins in actin cytoskeleton regulation. The yeast Saccharomyces cerevisiae proteome includes 29 SH3 domains distributed in 25 proteins. We have examined the direct involvement of these SH3 domains in actin polymerization using an in vitro polymerization assay on GST (glutathione S-transferase)-SH3-coated beads. As expected, not all SH3 domains show polymerization activity, and many recruit distinct partners as assessed by microscopy and pull-down experiments. One such partner, Las17p, the yeast homologue of WASP (Wiskott-Aldrich syndrome protein), was assayed because it stimulates actin nucleation via the Arp2/3 (actin-related protein 2/3) complex. Ultimately, proteins involved in specific biological processes, such as membrane trafficking, may also be recruited by some of these SH3 domains, shedding light on the SH3-containing proteins and actin cytoskeleton functions in these processes.
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Kaksonen M, Toret CP, Drubin DG. A modular design for the clathrin- and actin-mediated endocytosis machinery. Cell 2005; 123:305-20. [PMID: 16239147 DOI: 10.1016/j.cell.2005.09.024] [Citation(s) in RCA: 583] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 08/08/2005] [Accepted: 09/20/2005] [Indexed: 11/24/2022]
Abstract
Endocytosis depends on an extensive network of interacting proteins that execute a series of distinct subprocesses. Previously, we used live-cell imaging of six budding-yeast proteins to define a pathway for association of receptors, adaptors, and actin during endocytic internalization. Here, we analyzed the effects of 61 deletion mutants on the dynamics of this pathway, revealing functions for 15 proteins, and we analyzed the dynamics of 8 of these proteins. Our studies provide evidence for four protein modules that cooperate to drive coat formation, membrane invagination, actin-meshwork assembly, and vesicle scission during clathrin/actin-mediated endocytosis. We found that clathrin facilitates the initiation of endocytic-site assembly but is not needed for membrane invagination or vesicle formation. Finally, we present evidence that the actin-meshwork assembly that drives membrane invagination is nucleated proximally to the plasma membrane, opposite to the orientation observed for previously studied actin-assembly-driven motility processes.
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Affiliation(s)
- Marko Kaksonen
- Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA
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Ren G, Wang J, Brinkworth R, Winsor B, Kobe B, Munn AL. Verprolin Cytokinesis Function Mediated by the Hof One Trap Domain. Traffic 2005; 6:575-93. [PMID: 15941409 DOI: 10.1111/j.1600-0854.2005.00300.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In budding yeast, partitioning of the cytoplasm during cytokinesis can proceed via a pathway dependent on the contractile actomyosin ring, as in other eukaryotes, or alternatively via a septum deposition pathway dependent on an SH3 domain protein, Hof1/Cyk2 (the yeast PSTPIP1 ortholog). In dividing yeast cells, Hof1 forms a ring at the bud neck distinct from the actomyosin ring, and this zone is active in septum deposition. We previously showed the yeast Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP) ortholog, verprolin/Vrp1/End5, interacts with Hof1 and facilitates Hof1 recruitment to the bud neck. A Vrp1 fragment unable to interact with yeast WASP (Las17/Bee1), localize to the actin cytoskeleton or function in polarization of the cortical actin cytoskeleton nevertheless retains function in Hof1 recruitment and cytokinesis. Here, we show the ability of this Vrp1 fragment to bind the Hof1 SH3 domain via its Hof one trap (HOT) domain is critical for cytokinesis. The Vrp1 HOT domain consists of three tandem proline-rich motifs flanked by serines. Unexpectedly, the Hof1 SH3 domain itself is not required for cytokinesis and indeed appears to negatively regulate cytokinesis. The Vrp1 HOT domain promotes cytokinesis by binding to the Hof1 SH3 domain and counteracting its inhibitory effect.
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Affiliation(s)
- Gang Ren
- Laboratory of Yeast Cell Biology, Institute of Molecular and Cell Biology, A*STAR Biomedical Sciences Institutes, Singapore, 138673, Republic of Singapore
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Kadota J, Yamamoto T, Yoshiuchi S, Bi E, Tanaka K. Septin ring assembly requires concerted action of polarisome components, a PAK kinase Cla4p, and the actin cytoskeleton in Saccharomyces cerevisiae. Mol Biol Cell 2004; 15:5329-45. [PMID: 15371547 PMCID: PMC532014 DOI: 10.1091/mbc.e04-03-0254] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Septins are filament-forming proteins that function in cytokinesis in a wide variety of organisms. In budding yeast, the small GTPase Cdc42p triggers the recruitment of septins to the incipient budding site and the assembly of septins into a ring. We herein report that Bni1p and Cla4p, effectors of Cdc42p, are required for the assembly of the septin ring during the initiation of budding but not for its maintenance after the ring converts to a septin collar. In bni1Delta cla4-75-td mutant, septins were recruited to the incipient budding site. However, the septin ring was not assembled, and septins remained at the polarized growing sites. Bni1p, a formin family protein, is a member of the polarisome complex with Spa2p, Bud6p, and Pea2p. All spa2Delta cla4-75-td, bud6Delta cla4-75-td, and pea2Delta cla4-75-td mutants showed defects in septin ring assembly. Bni1p stimulates actin polymerization for the formation of actin cables. Point mutants of BNI1 that are specifically defective in actin cable formation also exhibited septin ring assembly defects in the absence of Cla4p. Consistently, treatment of cla4Delta mutant with the actin inhibitor latrunculin A inhibited septin ring assembly. Our results suggest that polarisome components and Cla4p are required for the initial assembly of the septin ring and that the actin cytoskeleton is involved in this process.
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Affiliation(s)
- Jun Kadota
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, 060-0815, Japan
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Saito K, Fujimura-Kamada K, Furuta N, Kato U, Umeda M, Tanaka K. Cdc50p, a protein required for polarized growth, associates with the Drs2p P-type ATPase implicated in phospholipid translocation in Saccharomyces cerevisiae. Mol Biol Cell 2004; 15:3418-32. [PMID: 15090616 PMCID: PMC452594 DOI: 10.1091/mbc.e03-11-0829] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cdc50p, a transmembrane protein localized to the late endosome, is required for polarized cell growth in yeast. Genetic studies suggest that CDC50 performs a function similar to DRS2, which encodes a P-type ATPase of the aminophospholipid translocase (APT) subfamily. At low temperatures, drs2Delta mutant cells exhibited depolarization of cortical actin patches and mislocalization of polarity regulators, such as Bni1p and Gic1p, in a manner similar to the cdc50Delta mutant. Both Cdc50p and Drs2p were localized to the trans-Golgi network and late endosome. Cdc50p was coimmunoprecipitated with Drs2p from membrane protein extracts. In cdc50Delta mutant cells, Drs2p resided on the endoplasmic reticulum (ER), whereas Cdc50p was found on the ER membrane in drs2Delta cells, suggesting that the association on the ER membrane is required for transport of the Cdc50p-Drs2p complex to the trans-Golgi network. Lem3/Ros3p, a homolog of Cdc50p, was coimmunoprecipitated with another APT, Dnf1p; Lem3p was required for exit of Dnf1p out of the ER. Both Cdc50p-Drs2p and Lem3p-Dnf1p were confined to the plasma membrane upon blockade of endocytosis, suggesting that these proteins cycle between the exocytic and endocytic pathways, likely performing redundant functions. Thus, phospholipid asymmetry plays an important role in the establishment of cell polarity; the Cdc50p/Lem3p family likely constitute potential subunits specific to unique P-type ATPases of the APT subfamily.
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Affiliation(s)
- Koji Saito
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, Sapporo 060-0815, Japan
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Abstract
Ubiquitination is a post-translational modification in which a small conserved peptide, ubiquitin, is appended to target proteins in the cell, through a series of complex enzymatic reactions. Recently, a particular form of ubiquitination, monoubiquitination, has emerged as a nonproteolytic reversible modification that controls protein function. In this review, we highlight recent findings on monoubiquitination as a signaling-induced modification, controlled, among others, by pathways originating from active receptor tyrosine kinases. Furthermore, we review the major cellular processes controlled by ubiquitin modification, including membrane trafficking, histone function, transcription regulation, DNA repair, and DNA replication.
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Affiliation(s)
- S Sigismund
- IFOM, The FIRC Institute for Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
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Mapes J, Ota IM. Nbp2 targets the Ptc1-type 2C Ser/Thr phosphatase to the HOG MAPK pathway. EMBO J 2003; 23:302-11. [PMID: 14685261 PMCID: PMC1271746 DOI: 10.1038/sj.emboj.7600036] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Accepted: 11/18/2003] [Indexed: 01/13/2023] Open
Abstract
The yeast high osmolarity glycerol (HOG) pathway signals via the Pbs2 MEK and the Hog1 MAPK, whose activity requires phosphorylation of Thr and Tyr in the activation loop. The Ptc1-type 2C Ser/Thr phosphatase (PP2C) inactivates Hog1 by dephosphorylating phospho-Thr, while the Ptp2 and Ptp3 protein tyrosine phosphatases dephosphorylate phospho-Tyr. In this work, we show that the SH3 domain-containing protein Nbp2 negatively regulates Hog1 by recruiting Ptc1 to the Pbs2-Hog1 complex. Consistent with this role, NBP2 acted as a negative regulator similar to PTC1 in phenotypic assays. Biochemical analysis showed that Nbp2, like Ptc1, was required to inactivate Hog1 during adaptation. As predicted for an adapter, deletion of NBP2 disrupted Ptc1-Pbs2 complex formation. Furthermore, Nbp2 contained separate binding sites for Ptc1 and Pbs2: the novel N-terminal domain bound Ptc1, while the SH3 domain bound Pbs2. In addition, the Pbs2 scaffold bound the Nbp2 SH3 via a Pro-rich motif distinct from that which binds the SH3 domain of the positive regulator Sho1. Thus, Nbp2 recruits Ptc1 to Pbs2, a scaffold for both negative and positive regulators.
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Affiliation(s)
- James Mapes
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - Irene M Ota
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- E-mail:
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Rodal AA, Manning AL, Goode BL, Drubin DG. Negative regulation of yeast WASp by two SH3 domain-containing proteins. Curr Biol 2003; 13:1000-8. [PMID: 12814545 DOI: 10.1016/s0960-9822(03)00383-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND WASp family proteins promote actin filament assembly by activating Arp2/3 complex and are regulated spatially and temporally to assemble specialized actin structures used in diverse cellular processes. Some WASp family members are autoinhibited until bound by activating ligands; however, regulation of the budding yeast WASp homolog (Las17/Bee1) has not yet been explored. RESULTS We isolated full-length Las17 and characterized its biochemical activities on yeast Arp2/3 complex. Purified Las17 was not autoinhibited; in this respect, it is more similar to SCAR/WAVE than to WASp proteins. Las17 was a much stronger activator of Arp2/3 complex than its carboxyl-terminal (WA) fragment. In addition, actin polymerization stimulated by Las17-Arp2/3 was much less sensitive to the inhibitory effects of profilin compared to polymerization stimulated by WA-Arp2/3. Two SH3 domain-containing binding partners of Las17, Sla1 and Bbc1, were purified and were shown to cooperate in inhibiting Las17 activity. The two SLA1 SH3 domains required for this inhibitory activity in vitro were also required in vivo, in combination with BBC1, for cell viability and normal actin organization. CONCLUSIONS Full-length Las17 is not autoinhibited and activates Arp2/3 complex more strongly than its WA domain alone, revealing an important role for the Las17 amino terminus in Arp2/3 complex activation. Two of the SH3 domain-containing ligands of Las17, Sla1 and Bbc1, cooperate to inhibit Las17 activity in vitro and are required for a shared function in actin organization in vivo. Our results show that, like SCAR/WAVE, WASp proteins can be controlled by negative regulation through the combined actions of multiple ligands.
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Affiliation(s)
- Avital A Rodal
- Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA
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Antón IM, Saville SP, Byrne MJ, Curcio C, Ramesh N, Hartwig JH, Geha RS. WIP participates in actin reorganization and ruffle formation induced by PDGF. J Cell Sci 2003; 116:2443-51. [PMID: 12724353 DOI: 10.1242/jcs.00433] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet-derived growth factor (PDGF) is a chemotactic factor for fibroblasts that triggers actin cytoskeleton reorganization by increasing the level of GTP-Rac, the activated form of a small Rho family GTPase. GTP-Rac induces membrane ruffling and lamellipodium formation that are required for adhesion, migration and macropinocytosis, among other functions. We have shown that WIP interacts with members of the Wiskott-Aldrich syndrome protein family and is essential for filopodium formation regulated by Cdc42 GTPase. In this report, we show that WIP participates in the actin reorganization that leads to ruffle formation. WIP overexpression in murine fibroblasts (3T3 cells) enhances ruffle formation in response to PDGF stimulation, as shown by immunofluorescence and electron and video microscopy. More importantly, microinjection of anti-WIP antibody or absence of WIP in murine fibroblasts results in decreased ruffle formation in response to PDGF treatment. Finally, overexpression of a modified form of WIP lacking the actin-binding site blocks PDGF-induced membrane ruffling. These data suggest a role for WIP in actin reorganization to form PDGF-induced ruffles. This is the first in vivo evidence in mammalian cells for a function of WIP dependent on its ability to bind actin.
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Affiliation(s)
- Inés M Antón
- Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Abstract
Ever since the discovery of class I myosins, the first nonmuscle myosins, about 30 years ago, the history of unconventional myosins has been linked to the organization and working of actin filaments. It slowly emerged from studies of class I myosins in lower eukaryotes that they are involved in mechanisms of endocytosis. Most interestingly, a flurry of recent findings assign a more active role to class I myosins in regulating the spatial and temporal organization of actin filament nucleation and elongation. The results highlight the multiple links between class I myosins and the major actin nucleator, the Arp2/3 complex, and its newly described activators. Two additional types of unconventional myosins, myosinIX, and Dictyostelium discoideum MyoM, have recently been tied to the signaling pathways controlling actin cytoskeleton remodeling. The present review surveys the links between these three classes of molecular motors and the complex cellular processes of endocytosis and actin dynamics, and concentrates on a working model accounting for the function of class I myosins via recruitment of the machinery responsible for actin nucleation and elongation.
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Affiliation(s)
- Thierry Soldati
- Department of Biological Sciences, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Toi H, Fujimura-Kamada K, Irie K, Takai Y, Todo S, Tanaka K. She4p/Dim1p interacts with the motor domain of unconventional myosins in the budding yeast, Saccharomyces cerevisiae. Mol Biol Cell 2003; 14:2237-49. [PMID: 12808026 PMCID: PMC194874 DOI: 10.1091/mbc.e02-09-0616] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
She4p/Dim1p, a member of the UNC-45/CRO1/She4p (UCS) domain-containing protein family, is required for endocytosis, polarization of actin cytoskeleton, and polarization of ASH1 mRNA in Saccharomyces cerevisiae. We show herein that She4p/Dim1p is involved in endocytosis and actin polarization through interactions with the type I myosins Myo3p and Myo5p. Two-hybrid and biochemical experiments showed that She4p/Dim1p interacts with the motor domain of Myo3/5p through its UCS domain. She4p/Dim1p was required for Myo5p localization to cortical patch-like structures. Using random mutagenesis of the motor region of MYO5, we identified four independent dominant point mutations that suppress the temperature-sensitive growth phenotype of the she4/dim1 null mutant. All of the amino acid substitutions caused by these mutations, V164I, N168I, N209S, and K377M, could suppress the defects of endocytosis and actin polarization of the she4/dim1 mutant as well. She4p/Dim1p also showed two-hybrid interactions with the motor domain of a type II myosin Myo1p and type V myosins Myo2p and Myo4p, and was required for proper localization of Myo4p, which regulates polarization of ASH1 mRNA. Our results suggest that She4p/Dim1p is required for structural integrity or regulation of the motor domain of unconventional myosins.
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Affiliation(s)
- Hirofumi Toi
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, Japan
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Kawasaki R, Fujimura-Kamada K, Toi H, Kato H, Tanaka K. The upstream regulator, Rsr1p, and downstream effectors, Gic1p and Gic2p, of the Cdc42p small GTPase coordinately regulate initiation of budding in Saccharomyces cerevisiae. Genes Cells 2003; 8:235-50. [PMID: 12622721 DOI: 10.1046/j.1365-2443.2003.00629.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cdc42p, a Rho family small GTPase, is essential for budding initiation in the yeast Saccharomyces cerevisiae. The homologous proteins Gic1p and Gic2p (Gic1/2p) are effectors of Cdc42p, but their precise functions remain unknown. Rsr1p/Bud1p is a Ras family small GTPase that controls the selection of the budding site. Previous observations suggested that Rsr1p-GTP recruits Cdc24p, a GDP/GTP exchange factor for Cdc42p, at the incipient bud site. However, this model only addresses how Rsr1p determines the budding site, because the rsr1 mutant normally initiates budding. RESULTS Here we show that a rsr1 gic1 gic2 mutant fails to initiate budding, resulting in unbudded, large, and multinucleated cells. Expression of a dominant active or dominant negative mutant of RSR1 also inhibited the growth of the gic1 gic2 mutant, suggesting that cycling of Rsr1p between the GTP- and GDP-bound forms is required for budding initiation in the gic1 gic2 mutant. Among the mutations in effectors of CDC42, only the gic1 gic2 mutation demonstrated a synthetic lethal interaction with rsr1. Increased gene dosage of CDC42 suppressed defects in budding initiation of rsr1 gic1 gic2 mutants containing additional mutations in other effectors of CDC42, including BNI1, CLA4 or STE20. The polarized localization of Bni1p-GFP (green fluorescent protein) and Cla4p-GFP was lost after depletion of Gic1p in the rsr1 gic2 mutant. CONCLUSION We propose that Gic1/2p may stabilize or maintain a complex consisting of Cdc42p-GTP and its effectors at the budding site, which are assembled by the action of the Rsr1p-Cdc24p system.
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Affiliation(s)
- Ryosuke Kawasaki
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, 060-0815, Japan
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Abstract
The Arp2/3 complex is necessary for nucleating the formation of branched networks of actin filaments at the cell cortex, and an increasing number of proteins able to activate the Arp2/3 complex have been described. The Wiskott-Aldrich syndrome protein (WASP) family and cortactin comprise the large majority of the known activators. WASPs bind to Arp2/3 via an acidic (A) domain, and a WH2 domain appears to bring an actin monomer to Arp2/3, promoting the nucleation of the new filament. Cortactin also binds the Arp2/3 complex via an A domain; however, it also binds to actin filaments, which helps activate the Arp2/3 complex and stabilise the newly created branches between the filaments.
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Affiliation(s)
- Alissa M Weaver
- Department of Cell Biology, Washington University School of Medicine, St Louis, MO 63130, USA
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40
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Abstract
The availability of complete genome sequences for a variety of organisms, coupled with novel approaches that allow evaluation of the functions of thousands of genes in parallel, have the potential to greatly impact on cell biology research. Functional genomic approaches in Saccharomyces cerevisiae are beginning to make significant contributions to the understanding of complex biological systems.
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Affiliation(s)
- Adam C Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, 94720-3202, USA
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Misu K, Fujimura-Kamada K, Ueda T, Nakano A, Katoh H, Tanaka K. Cdc50p, a conserved endosomal membrane protein, controls polarized growth in Saccharomyces cerevisiae. Mol Biol Cell 2003; 14:730-47. [PMID: 12589066 PMCID: PMC150004 DOI: 10.1091/mbc.e02-06-0314] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During the cell cycle of the yeast Saccharomyces cerevisiae, the actin cytoskeleton and the growth of cell surface are polarized, mediating bud emergence, bud growth, and cytokinesis. We identified CDC50 as a multicopy suppressor of the myo3 myo5-360 temperature-sensitive mutant, which is defective in organization of cortical actin patches. The cdc50 null mutant showed cold-sensitive cell cycle arrest with a small bud as reported previously. Cortical actin patches and Myo5p, which are normally localized to polarization sites, were depolarized in the cdc50 mutant. Furthermore, actin cables disappeared, and Bni1p and Gic1p, effectors of the Cdc42p small GTPase, were mislocalized in the cdc50 mutant. As predicted by its amino acid sequence, Cdc50p appears to be a transmembrane protein because it was solubilized from the membranes by detergent treatment. Cdc50p colocalized with Vps21p in endosomal compartments and was also localized to the class E compartment in the vps27 mutant. The cdc50 mutant showed defects in a late stage of endocytosis but not in the internalization step. It showed, however, only modest defects in vacuolar protein sorting. Our results indicate that Cdc50p is a novel endosomal protein that regulates polarized cell growth.
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Affiliation(s)
- Kenjiro Misu
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, 060-0815, Japan
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Soulard A, Lechler T, Spiridonov V, Shevchenko A, Shevchenko A, Li R, Winsor B. Saccharomyces cerevisiae Bzz1p is implicated with type I myosins in actin patch polarization and is able to recruit actin-polymerizing machinery in vitro. Mol Cell Biol 2002; 22:7889-906. [PMID: 12391157 PMCID: PMC134730 DOI: 10.1128/mcb.22.22.7889-7906.2002] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Saccharomyces cerevisiae, the WASP (Wiskott-Aldrich syndrome protein) homologue Las17p (also called Bee1p) is an important component of cortical actin patches. Las17p is part of a high-molecular-weight protein complex that regulates Arp2/3 complex-dependent actin polymerization at the cell cortex and that includes the type I myosins Myo3p and Myo5p and verprolin (Vrp1p). To identify other factors implicated with this complex in actin regulation, we isolated proteins that bind to Las17p by two-hybrid screening and affinity chromatography. Here, we report the characterization of Lsb7/Bzz1p (for Las seventeen binding protein 7), an Src homology 3 (SH3) domain protein that interacts directly with Las17p via a polyproline-SH3 interaction. Bzz1p coimmunoprecipitates in a complex with Las17p, Vrp1p, Myo3/5p, Bbc1p, Hsp70p, and actin. It colocalizes with cortical actin patches and with Las17p. This localization is dependent on Las17p, but not on F-actin. Bzz1p interacts physically and genetically with type I myosins. While deletion of BZZ1 shows no obvious phenotype, simultaneous deletion of the BZZ1, MYO3, and MYO5 genes is lethal. Overexpression of Bzz1p inhibits cell growth, and a bzz1Delta myo5Delta double mutant is unable to restore actin polarity after NaCl stress. Finally, Bzz1p in vitro is able to recruit a functional actin polymerization machinery through its SH3 domains. Its interactions with Las17p, Vrp1p, and the type I myosins are essential for this process. This suggests that Bzz1p could be implicated in the regulation of actin polymerization.
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Affiliation(s)
- Alexandre Soulard
- Modèles levure des Pathologies Humaines, F.R.E. 2375 du Centre National de la Recheche Scientifique, Strasbourg, France
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Current awareness on yeast. Yeast 2002; 19:995-1002. [PMID: 12125056 DOI: 10.1002/yea.827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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