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Chen YJ, Wu KY, Lin SF, Huang SH, Hsu HC, Hsu HM. PIP2 regulating calcium signal modulates actin cytoskeleton-dependent cytoadherence and cytolytic capacity in the protozoan parasite Trichomonas vaginalis. PLoS Pathog 2023; 19:e1011891. [PMID: 38109416 PMCID: PMC10758264 DOI: 10.1371/journal.ppat.1011891] [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: 08/05/2023] [Revised: 01/01/2024] [Accepted: 12/08/2023] [Indexed: 12/20/2023] Open
Abstract
Trichomonas vaginalis is a prevalent causative agent that causes trichomoniasis leading to uropathogenic inflammation in the host. The crucial role of the actin cytoskeleton in T. vaginalis cytoadherence has been established but the associated signaling has not been fully elucidated. The present study revealed that the T. vaginalis second messenger PIP2 is located in the recurrent flagellum of the less adherent isolate and is more abundant around the cell membrane of the adherent isolates. The T. vaginalis phosphatidylinositol-4-phosphate 5-kinase (TvPI4P5K) with conserved activity phosphorylating PI(4)P to PI(4, 5)P2 was highly expressed in the adherent isolate and partially colocalized with PIP2 on the plasma membrane but with discrete punctate signals in the cytoplasm. Plasma membrane PIP2 degradation by phospholipase C (PLC)-dependent pathway concomitant with increasing intracellular calcium during flagellate-amoeboid morphogenesis. This could be inhibited by Edelfosine or BAPTA simultaneously repressing parasite actin assembly, morphogenesis, and cytoadherence with inhibitory effects similar to the iron-depleted parasite, supporting the significance of PIP2 and iron in T. vaginalis colonization. Intriguingly, iron is required for the optimal expression and cell membrane trafficking of TvPI4P5K for in situ PIP2 production, which was diminished in the iron-depleted parasites. TvPI4P5K-mediated PIP2 signaling may coordinate with iron to modulate T. vaginalis contact-dependent cytolysis to influence host cell viability. These observations provide novel insights into T. vaginalis cytopathogenesis during the host-parasite interaction.
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Affiliation(s)
- Yen-Ju Chen
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Kuan-Yi Wu
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shu-Fan Lin
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Sung-Hsi Huang
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, Taiwan
| | - Heng-Cheng Hsu
- Department of Obstetrics and Gynecology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Surgery, National Taiwan University Cancer Center, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hong-Ming Hsu
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
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2
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Benson A, McMurray M. Simultaneous co-overexpression of Saccharomyces cerevisiae septins Cdc3 and Cdc10 drives pervasive, phospholipid-, and tag-dependent plasma membrane localization. Cytoskeleton (Hoboken) 2023; 80:199-214. [PMID: 37098755 PMCID: PMC10524705 DOI: 10.1002/cm.21762] [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: 12/01/2022] [Revised: 03/29/2023] [Accepted: 04/17/2023] [Indexed: 04/27/2023]
Abstract
Septin proteins contribute to many eukaryotic processes involving cellular membranes. In the budding yeast Saccharomyces cerevisiae, septin hetero-oligomers interact with the plasma membrane (PM) almost exclusively at the future site of cytokinesis. While multiple mechanisms of membrane recruitment have been identified, including direct interactions with specific phospholipids and curvature-sensitive interactions via amphipathic helices, these do not fully explain why yeast septins do not localize all over the inner leaflet of the PM. While engineering an inducible split-yellow fluorescent protein (YFP) system to measure the kinetics of yeast septin complex assembly, we found that ectopic co-overexpression of two tagged septins, Cdc3 and Cdc10, resulted in nearly uniform PM localization, as well as perturbation of endogenous septin function. Septin localization and function in gametogenesis were also perturbed. PM localization required the C-terminal YFP fragment fused to the C terminus of Cdc3, the septin-associated kinases Cla4 and Gin4, and phosphotidylinositol-4,5-bis-phosphate (PI[4,5]P2 ), but not the putative PI(4,5)P2 -binding residues in Cdc3. Endogenous Cdc10 was recruited to the PM, likely contributing to the functional interference. PM-localized septins did not exchange with the cytosolic pool, indicative of stable polymers. These findings provide new clues as to what normally restricts septin localization to specific membranes.
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Affiliation(s)
- Aleyna Benson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michael McMurray
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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3
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Nunez G, Zhang K, Mogbheli K, Hollingsworth NM, Neiman AM. Recruitment of the lipid kinase Mss4 to the meiotic spindle pole promotes prospore membrane formation in Saccharomyces cerevisiae. Mol Biol Cell 2023; 34:ar33. [PMID: 36857169 PMCID: PMC10092644 DOI: 10.1091/mbc.e22-11-0515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Spore formation in the budding yeast, Saccharomyces cerevisiae, involves de novo creation of four prospore membranes, each of which surrounds a haploid nucleus resulting from meiosis. The meiotic outer plaque (MOP) is a meiosis-specific protein complex associated with each meiosis II spindle pole body (SPB). Vesicle fusion on the MOP surface creates an initial prospore membrane anchored to the SPB. Ady4 is a meiosis-specific MOP component that stabilizes the MOP-prospore membrane interaction. We show that Ady4 recruits the lipid kinase, Mss4, to the MOP. MSS4 overexpression suppresses the ady4∆ spore formation defect, suggesting that a specific lipid environment provided by Mss4 promotes maintenance of prospore membrane attachment to MOPs. The meiosis-specific Spo21 protein is an essential structural MOP component. We show that the Spo21 N terminus contains an amphipathic helix that binds to prospore membranes. A mutant in SPO21 that removes positive charges from this helix shares phenotypic similarities to ady4∆. We propose that Mss4 generates negatively charged lipids in prospore membranes that enhance binding by the positively charged N terminus of Spo21, thereby providing a mechanism by which the MOP-prospore membrane interaction is stabilized.
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Affiliation(s)
- Greisly Nunez
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Kai Zhang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Kaveh Mogbheli
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Nancy M Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
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4
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Llorente A, Arora GK, Grenier SF, Emerling BM. PIP kinases: A versatile family that demands further therapeutic attention. Adv Biol Regul 2023; 87:100939. [PMID: 36517396 PMCID: PMC9992244 DOI: 10.1016/j.jbior.2022.100939] [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: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are membrane-localized phospholipids that regulate a plethora of essential cellular processes. These lipid signaling molecules are critical for cell homeostasis and therefore their levels are strictly regulated by the coordinated action of several families of lipid kinases and phosphatases. In this review, we provide a focused perspective on the phosphatidylinositol phosphate kinase (PIPK) family and the three subfamilies that compose it: Type I PIPKs or phosphatidylinositol-4-phosphate 5-kinases (PI4P5Ks), Type II PIPKs or phosphatidylinositol-5-phosphate 4-kinases (PI5P4Ks), and Type III PIPKs or phosphatidylinositol-3-phosphate 5-kinases (PIKfyve). Each subfamily is responsible for catalyzing a hydroxyl phosphorylation on specific phosphoinositide species to generate a double phosphorylated lipid, therefore regulating the levels of both substrate and product. Here, we summarize our current knowledge about the functions and regulation of each PIPK subfamily. Further, we highlight the roles of these kinases in various in vivo genetic models and give an overview of their involvement in multiple pathological conditions. The phosphoinositide field has been long focused on targeting PI3K signaling, but growing evidence suggests that it is time to draw attention to the other phosphoinositide kinases. The discovery of the involvement of PIPKs in the pathogenesis of multiple diseases has prompted substantial efforts to turn these enzymes into pharmacological targets. An increasingly refined knowledge of the biology of PIPKs in a variety of in vitro and in vivo models will facilitate the development of effective approaches for therapeutic intervention with the potential to translate into meaningful clinical benefits for patients suffering from cancer, immunological and infectious diseases, and neurodegenerative disorders.
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Affiliation(s)
- Alicia Llorente
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Gurpreet K Arora
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Shea F Grenier
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Brooke M Emerling
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA.
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5
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Hansen SD, Lee AA, Duewell BR, Groves JT. Membrane-mediated dimerization potentiates PIP5K lipid kinase activity. eLife 2022; 11:73747. [PMID: 35976097 PMCID: PMC9470164 DOI: 10.7554/elife.73747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 08/16/2022] [Indexed: 11/28/2022] Open
Abstract
The phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family of lipid-modifying enzymes generate the majority of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] lipids found at the plasma membrane in eukaryotic cells. PI(4,5)P2 lipids serve a critical role in regulating receptor activation, ion channel gating, endocytosis, and actin nucleation. Here, we describe how PIP5K activity is regulated by cooperative binding to PI(4,5)P2 lipids and membrane-mediated dimerization of the kinase domain. In contrast to constitutively dimeric phosphatidylinositol 5-phosphate 4-kinase (PIP4K, type II PIPK), solution PIP5K exists in a weak monomer–dimer equilibrium. PIP5K monomers can associate with PI(4,5)P2-containing membranes and dimerize in a protein density-dependent manner. Although dispensable for cooperative PI(4,5)P2 binding, dimerization enhances the catalytic efficiency of PIP5K through a mechanism consistent with allosteric regulation. Additionally, dimerization amplifies stochastic variation in the kinase reaction velocity and strengthens effects such as the recently described stochastic geometry sensing. Overall, the mechanism of PIP5K membrane binding creates a broad dynamic range of lipid kinase activities that are coupled to the density of PI(4,5)P2 and membrane-bound kinase.
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Affiliation(s)
- Scott D Hansen
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, United States
| | - Albert A Lee
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Benjamin R Duewell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, United States
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
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6
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Hassing B, Candy A, Eaton CJ, Fernandes TR, Mesarich CH, Di Pietro A, Scott B. Localisation of phosphoinositides in the grass endophyte Epichloë festucae and genetic and functional analysis of key components of their biosynthetic pathway in E. festucae symbiosis and Fusarium oxysporum pathogenesis. Fungal Genet Biol 2022; 159:103669. [PMID: 35114379 DOI: 10.1016/j.fgb.2022.103669] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/15/2022] [Accepted: 01/27/2022] [Indexed: 11/24/2022]
Abstract
Phosphoinositides (PI) are essential components of eukaryotic membranes and function in a large number of signaling processes. While lipid second messengers are well studied in mammals and yeast, their role in filamentous fungi is poorly understood. We used fluorescent PI-binding molecular probes to localize the phosphorylated phosphatidylinositol species PI[3]P, PI[3,5]P2, PI[4]P and PI[4,5]P2 in hyphae of the endophyte Epichloë festucae in axenic culture and during interaction with its grass host Lolium perenne. We also analysed the roles of the phosphatidylinositol-4-phosphate 5-kinase MssD and the predicted phosphatidylinositol-3,4,5-triphosphate 3-phosphatase TepA, a homolog of the mammalian tumour suppressor protein PTEN. Deletion of tepA in E. festucae and in the root-infecting tomato pathogen Fusarium oxysporum had no impact on growth in culture or the host interaction phenotype. However, this mutation did enable the detection of PI[3,4,5]P3 in septa and mycelium of E. festucae and showed that TepA is required for chemotropism in F. oxysporum. The identification of PI[3,4,5]P3 in ΔtepA strains suggests that filamentous fungi are able to generate PI[3,4,5]P3 and that fungal PTEN homologs are functional lipid phosphatases. The F. oxysporum chemotropism defect suggests a conserved role of PTEN homologs in chemotaxis across protists, fungi and mammals.
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Affiliation(s)
- Berit Hassing
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Alyesha Candy
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Carla J Eaton
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Tania R Fernandes
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba, Spain
| | - Carl H Mesarich
- Bio-Protection Research Centre, New Zealand; School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Antonio Di Pietro
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba, Spain
| | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand.
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7
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The GTPase Arf1 Is a Determinant of Yeast Vps13 Localization to the Golgi Apparatus. Int J Mol Sci 2021; 22:ijms222212274. [PMID: 34830155 PMCID: PMC8619211 DOI: 10.3390/ijms222212274] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 12/12/2022] Open
Abstract
VPS13 proteins are evolutionarily conserved. Mutations in the four human genes (VPS13A-D) encoding VPS13A-D proteins are linked to developmental or neurodegenerative diseases. The relationship between the specific localization of individual VPS13 proteins, their molecular functions, and the pathology of these diseases is unknown. Here we used a yeast model to establish the determinants of Vps13's interaction with the membranes of Golgi apparatus. We analyzed the different phenotypes of the arf1-3 arf2Δ vps13∆ strain, with reduced activity of the Arf1 GTPase, the master regulator of Golgi function and entirely devoid of Vps13. Our analysis led us to propose that Vps13 and Arf1 proteins cooperate at the Golgi apparatus. We showed that Vps13 binds to the Arf1 GTPase through its C-terminal Pleckstrin homology (PH)-like domain. This domain also interacts with phosphoinositol 4,5-bisphosphate as it was bound to liposomes enriched with this lipid. The homologous domain of VPS13A exhibited the same behavior. Furthermore, a fusion of the PH-like domain of Vps13 to green fluorescent protein was localized to Golgi structures in an Arf1-dependent manner. These results suggest that the PH-like domains and Arf1 are determinants of the localization of VPS13 proteins to the Golgi apparatus in yeast and humans.
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8
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The distribution of phosphatidylinositol 4,5-bisphosphate in the budding yeast plasma membrane. Histochem Cell Biol 2021; 156:109-121. [PMID: 34052862 DOI: 10.1007/s00418-021-01989-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2021] [Indexed: 01/07/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is generated through phosphorylation of phosphatidylinositol 4-phosphate (PtdIns(4)P) by Mss4p, the only PtdIns phosphate 5-kinase in yeast cells. PtdIns(4,5)P2 is involved in various kinds of yeast functions. PtdIns(4)P is not only the immediate precursor of PtdIns(4,5)P2, but also an essential signaling molecule in the plasma membrane, Golgi, and endosomal system. To analyze the distribution of PtdIns(4,5)P2 and PtdIns(4)P in the yeast plasma membrane at a nanoscale level, we employed a freeze-fracture electron microscopy (EM) method that physically immobilizes lipid molecules in situ. It has been reported that the plasma membrane of budding yeast can be divided into three distinct areas: furrowed, hexagonal, and undifferentiated flat. Previously, using the freeze-fracture EM method, we determined that PtdIns(4)P is localized in the undifferentiated flat area, avoiding the furrowed and hexagonal areas of the plasma membrane. In the present study, we found that PtdIns(4,5)P2 was localized in the cytoplasmic leaflet of the plasma membrane, and concentrated in the furrowed area. There are three types of PtdIns 4-kinases which are encoded by stt4, pik1, and lsb6. The labeling density of PtdIns(4)P in the plasma membrane significantly decreased in both pik1ts and stt4ts mutants. However, the labeling densities of PtdIns(4,5)P2 in the plasma membrane of both the pik1ts and stt4ts mutants were comparable to that of the wild type yeast. These results suggest that PtdIns(4)P produced by either Pik1p or Stt4p is immediately phosphorylated by Mss4p and converted to PtdIns(4,5)P2 at the plasma membrane.
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9
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Lin MH, Kuo PC, Chiu YC, Chang YY, Chen SC, Hsu CH. The crystal structure of protein-transporting chaperone BCP1 from Saccharomyces cerevisiae. J Struct Biol 2020; 212:107605. [PMID: 32805410 DOI: 10.1016/j.jsb.2020.107605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/04/2020] [Accepted: 08/12/2020] [Indexed: 11/25/2022]
Abstract
BCP1 is a protein enriched in the nucleus that is required for Mss4 nuclear export and identified as the chaperone of ribosomal protein Rpl23 in Saccharomyces cerevisiae. According to sequence homology, BCP1 is related to the mammalian BRCA2-interacting protein BCCIP and belongs to the BCIP protein family (PF13862) in the Pfam database. However, the BCIP family has no discernible similarity to proteins with known structure. Here, we report the crystal structure of BCP1, presenting an α/β fold in which the central antiparallel β-sheet is flanked by helices. Protein structural classification revealed that BCP1 has similarity to the GNAT superfamily but no conserved substrate-binding residues. Further modeling and protein-protein docking work provide a plausible model to explain the interaction between BCP1 and Rpl23. Our structural analysis presents the first structure of BCIP family and provides a foundation for understanding the molecular basis of BCP1 as a chaperone of Rpl23 for ribosome biosynthesis.
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Affiliation(s)
- Meng-Hsuan Lin
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan; Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Po-Chih Kuo
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yi-Chih Chiu
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Yu-Yung Chang
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Sheng-Chia Chen
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Chun-Hua Hsu
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan; Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan.
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10
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Wang DG, Paddock MN, Lundquist MR, Sun JY, Mashadova O, Amadiume S, Bumpus TW, Hodakoski C, Hopkins BD, Fine M, Hill A, Yang TJ, Baskin JM, Dow LE, Cantley LC. PIP4Ks Suppress Insulin Signaling through a Catalytic-Independent Mechanism. Cell Rep 2020; 27:1991-2001.e5. [PMID: 31091439 PMCID: PMC6619495 DOI: 10.1016/j.celrep.2019.04.070] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 02/06/2019] [Accepted: 04/16/2019] [Indexed: 12/17/2022] Open
Abstract
Insulin stimulates the conversion of phosphatidylino-sitol-4,5-bisphosphate (PI(4,5)P2) to phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3), which mediates downstream cellular responses. PI(4,5)P2 is produced by phosphatidylinositol-4-phosphate 5-kinases (PIP5Ks) and by phosphatidylinositol-5-phos-phate 4-kinases (PIP4Ks). Here, we show that the loss of PIP4Ks (PIP4K2A, PIP4K2B, and PIP4K2C) in vitro results in a paradoxical increase in PI(4,5)P2 and a concomitant increase in insulin-stimulated production of PI(3,4,5)P3. The reintroduction of either wild-type or kinase-dead mutants of the PIP4Ks restored cellular PI(4,5)P2 levels and insulin stimulation of the PI3K pathway, suggesting a catalytic-independent role of PIP4Ks in regulating PI(4,5)P2 levels. These effects are explained by an increase in PIP5K activity upon the deletion of PIP4Ks, which normally suppresses PIP5K activity through a direct binding interaction mediated by the N-terminal motif VMLϕFPDD of PIP4K. Our work uncovers an allosteric function of PIP4Ks in suppressing PIP5K-mediated PI(4,5)P2 synthesis and insulin-dependent conversion to PI(3,4,5)P3 and suggests that the pharmacological depletion of PIP4K enzymes could represent a strategy for enhancing insulin signaling. PI(4,5)P2 is produced by both phosphatidylinositol-4-phosphate 5-kinases (PIP5Ks) and by phosphatidylinositol-5-phosphate 4-kinases (PIP4Ks). Wang et al. report an allosteric function of a conserved N-terminal motif of PIP4Ks in suppressing PIP5K-mediated PI(4,5)P2 synthesis and insulin-dependent conversion to PI(3,4,5) P3. This non-catalytic role has implications for the development of PIP4K targeted therapies.
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Affiliation(s)
- Diana G Wang
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell Medicine/Rockefeller University/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Marcia N Paddock
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Hematology and Oncology Division, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA
| | - Mark R Lundquist
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Janet Y Sun
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Oksana Mashadova
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Solomon Amadiume
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Timothy W Bumpus
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Cindy Hodakoski
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | | | - Matthew Fine
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Amanda Hill
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - T Jonathan Yang
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Lukas E Dow
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Hematology and Oncology Division, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA; Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
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11
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Zhang B, Peng L, Zhu N, Yu Q, Li M. Novel role of the phosphatidylinositol phosphatase Sac1 in membrane homeostasis and polarized growth in Candida albicans. Int J Med Microbiol 2020; 310:151418. [PMID: 32245626 DOI: 10.1016/j.ijmm.2020.151418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/16/2020] [Accepted: 03/19/2020] [Indexed: 10/24/2022] Open
Abstract
Phosphoinositides (PIPs) are one kind of membrane components functioning in many intracellular processes, especially in signaling transduction and membrane transport. Phosphatidylinositide phosphatases (PIPases) are specifically important for the PIP homeostasis in cell. In our previous study, we have identified the actin-related protein CaSac1 in Candida albicans, while its functional mechanisms in regulating membrane homeostasis has not been identified. Here, we show that the PIPase CaSac1 is a main membrane-related protein and regulates hyphal polarization by governing phosphoinositide dynamic and plasma membrane (PM) electrostatic field. Deletion of CaSAC1 resulted in large-scale abnormal redistribution of phosphatidylinositide 4-phosphate (PI4P) from the endomembrane to the PM. This abnormality further led to disturbance of the PM's negative electrostatic field and abnormally spotted distribution of phosphatidylinositide 4,5-bisphosphate (PI(4,5)P2). These changes led to a severe defect in polarized hyphal growth, which could be diminished with recovery of the PM's negative electrostatic field by the anionic polymer polyacrylic acid (PAA). This study revealed that the PIPase CaSac1 plays an essential role in regulating membrane homeostasis and membrane traffic, contributing to establishment of polarized hyphal growth.
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Affiliation(s)
- Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Liping Peng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China.
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12
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CircRNA_0001449 disturbs phosphatidylinositol homeostasis and AKT activity by enhancing Osbpl5 translation in transient cerebral ischemia. Redox Biol 2020; 34:101459. [PMID: 32086008 PMCID: PMC7327991 DOI: 10.1016/j.redox.2020.101459] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/02/2020] [Accepted: 02/07/2020] [Indexed: 12/26/2022] Open
Abstract
Phosphatidylinositol-3,4,5-trisphosphate [PI(3,4,5)P3] is a phosphorylated derivative of phosphatidylinositol 4-phosphate [PI(4)P] and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], which recruit and activate AKT in the plasma membrane (PM) to promote cellular survival. ORP5 anchors at the endoplasmic reticulum (ER)-PM contact sites and acts as a PI(4)P and PI(4,5)P2/phosphatidylserine (PS) exchanger. Here, a lipidomics analysis of the sensorimotor cortex revealed that transient middle cerebral artery occlusion (tMCAO) disturbs the homeostasis of phosphatidylinositols (PIs) and PS between the PM and ER. Conditional knockout mice showed that ORP5 contributes to this abnormal distribution. Abolishing the ORP5 gene significantly inhibited apoptosis and autophagy. RNA sequencing and RNA pull down analyses confirmed a competing endogenous RNA pathway in which circ_0001449 sponges miR-124-3p and miR-32-5p to promote Osbpl5 translation. Our data showed that circRNA_0001449 regulates membrane homeostasis via ORP5 and is involved in the AKT survival pathway. In sensorimotor cortex, lipids homeostasis of the PM and ER is disrupted after transient cerebral ischemia. ORP5 upregulation reduces the PI(3,4,5)P3 and its derivatives in the PM, thus weakens the AKT activity. Circ_0001449 competes with Osbpl5 mRNA to bind to miR-124-3p and miR-32-5p, which enhances the ORP5 protein level.
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13
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Moosavi B, Gao M, Zhu XL, Yang GF. The anti-cancer compound Schweinfurthin A targets Osh2 and disrupts lipid metabolism in the yeast model. Bioorg Chem 2019; 94:103471. [PMID: 31813476 DOI: 10.1016/j.bioorg.2019.103471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/09/2019] [Accepted: 11/23/2019] [Indexed: 12/17/2022]
Abstract
Schweinfurthin A (Sch A) is a natural product with a selective and strong anti-cancer effect. Although it is known to target oxysterol binding proteins, the detailed mode of action is not well understood. Here, we provide strong evidence that yeast cells can be used as a eukaryotic model system to decipher the molecular modes of Sch A. We show that Sch A (100 µM) targets Osh2 (a yeast oxysterol binding protein homolog) genetically and taking advantage of computational chemistry indicate that the tetrahydro-2H-xanthene portion of Sch A forms H-bonds with residues Ser105, Val113, and Lys201, while its isoprenoid side chain is placed in a hydrophobic pocket lined by the side chains of Leu41, Leu45, Leu58, Met56, and Phe174 in Osh2. This model suggests that Sch A occupies the same binding pocket in Osh2 which is occupied by its natural substrate, ergosterol. Osh proteins transport sterol and PI(4)P in a cyclic manner between two membranes. Therefore, we suggest that Sch A interferes with this function of Osh2. In support of this hypothesis, we show that Sch A toxicity rate changes upon manipulating the enzymes that modify the levels of sterol and PI(4)P. This approach also informs how Sch A exerts its toxic effect in yeast cells. These enzymes include Coq1, Sac1, Plc1, Stt4, Pik1, and Mss4. We demonstrate that Coq1 an enzyme required for coenzyme Q synthesis (also involved in sterol metabolism indirectly), Sac1, and Stt4 the enzymes governing PI(4)P level modify Sch A toxicity and finally propose Sch A disrupts sterol/PI(4)P exchange between membranes by occupying the sterol/PI(4)P binding pocket in Osh2.
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Affiliation(s)
- Behrooz Moosavi
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
| | - Mengqi Gao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
| | - Xiao-Lei Zhu
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
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14
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Zahumensky J, Malinsky J. Role of MCC/Eisosome in Fungal Lipid Homeostasis. Biomolecules 2019; 9:E305. [PMID: 31349700 PMCID: PMC6723945 DOI: 10.3390/biom9080305] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 12/11/2022] Open
Abstract
One of the best characterized fungal membrane microdomains is the MCC/eisosome. The MCC (membrane compartment of Can1) is an evolutionarily conserved ergosterol-rich plasma membrane domain. It is stabilized on its cytosolic face by the eisosome, a hemitubular protein complex composed of Bin/Amphiphysin/Rvs (BAR) domain-containing Pil1 and Lsp1. These two proteins bind directly to phosphatidylinositol 4,5-bisphosphate and promote the typical furrow-like shape of the microdomain, with highly curved edges and bottom. While some proteins display stable localization in the MCC/eisosome, others enter or leave it under particular conditions, such as misbalance in membrane lipid composition, changes in membrane tension, or availability of specific nutrients. These findings reveal that the MCC/eisosome, a plasma membrane microdomain with distinct morphology and lipid composition, acts as a multifaceted regulator of various cellular processes including metabolic pathways, cellular morphogenesis, signalling cascades, and mRNA decay. In this minireview, we focus on the MCC/eisosome's proposed role in the regulation of lipid metabolism. While the molecular mechanisms of the MCC/eisosome function are not completely understood, the idea of intracellular processes being regulated at the plasma membrane, the foremost barrier exposed to environmental challenges, is truly exciting.
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Affiliation(s)
- Jakub Zahumensky
- Department of Microscopy, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Jan Malinsky
- Department of Microscopy, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic.
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15
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Lau N, Haeberle AL, O’Keeffe BJ, Latomanski EA, Celli J, Newton HJ, Knodler LA. SopF, a phosphoinositide binding effector, promotes the stability of the nascent Salmonella-containing vacuole. PLoS Pathog 2019; 15:e1007959. [PMID: 31339948 PMCID: PMC6682159 DOI: 10.1371/journal.ppat.1007959] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 08/05/2019] [Accepted: 07/02/2019] [Indexed: 12/19/2022] Open
Abstract
The enteric bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), utilizes two type III secretion systems (T3SSs) to invade host cells, survive and replicate intracellularly. T3SS1 and its dedicated effector proteins are required for bacterial entry into non-phagocytic cells and establishment and trafficking of the nascent Salmonella-containing vacuole (SCV). Here we identify the first T3SS1 effector required to maintain the integrity of the nascent SCV as SopF. SopF associates with host cell membranes, either when translocated by bacteria or ectopically expressed. Recombinant SopF binds to multiple phosphoinositides in protein-lipid overlays, suggesting that it targets eukaryotic cell membranes via phospholipid interactions. In yeast, the subcellular localization of SopF is dependent on the activity of Mss4, a phosphatidylinositol 4-phosphate 5-kinase that generates PI(4,5)P2 from PI(4)P, indicating that membrane recruitment of SopF requires specific phospholipids. Ectopically expressed SopF partially colocalizes with specific phosphoinositide pools present on the plasma membrane in mammalian cells and with cytoskeletal-associated markers at the leading edge of cells. Translocated SopF concentrates on plasma membrane ruffles and around intracellular bacteria, presumably on the SCV. SopF is not required for bacterial invasion of non-phagocytic cells but is required for maintenance of the internalization vacuole membrane as infection with a S. Typhimurium ΔsopF mutant led to increased lysis of the SCV compared to wild type bacteria. Our structure-function analysis shows that the carboxy-terminal seven amino acids of SopF are essential for its membrane association in host cells and to promote SCV membrane stability. We also describe that SopF and another T3SS1 effector, SopB, act antagonistically to modulate nascent SCV membrane dynamics. In summary, our study highlights that a delicate balance of type III effector activities regulates the stability of the Salmonella internalization vacuole.
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Affiliation(s)
- Nicole Lau
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Amanda L. Haeberle
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Brittany J. O’Keeffe
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Eleanor A. Latomanski
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Jean Celli
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Hayley J. Newton
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (LAK); (HJN)
| | - Leigh A. Knodler
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
- * E-mail: (LAK); (HJN)
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16
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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17
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Martinez Marshall MN, Emmerstorfer-Augustin A, Leskoske KL, Zhang LH, Li B, Thorner J. Analysis of the roles of phosphatidylinositol-4,5- bisphosphate and individual subunits in assembly, localization, and function of Saccharomyces cerevisiae target of rapamycin complex 2. Mol Biol Cell 2019; 30:1555-1574. [PMID: 30969890 PMCID: PMC6724684 DOI: 10.1091/mbc.e18-10-0682] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Eukaryotic cell survival requires maintenance of plasma membrane (PM) homeostasis in response to environmental insults and changes in lipid metabolism. In yeast, a key regulator of PM homeostasis is target of rapamycin (TOR) complex 2 (TORC2), a multiprotein complex containing the evolutionarily conserved TOR protein kinase isoform Tor2. PM localization is essential for TORC2 function. One core TORC2 subunit (Avo1) and two TORC2-associated regulators (Slm1 and Slm2) contain pleckstrin homology (PH) domains that exhibit specificity for binding phosphatidylinositol-4,5-bisphosphate (PtdIns4,5P2). To investigate the roles of PtdIns4,5P2 and constituent subunits of TORC2, we used auxin-inducible degradation to systematically eliminate these factors and then examined localization, association, and function of the remaining TORC2 components. We found that PtdIns4,5P2 depletion significantly reduced TORC2 activity, yet did not prevent PM localization or disassembly of TORC2. Moreover, truncated Avo1 (lacking its C-terminal PH domain) was still recruited to the PM and supported growth. Even when all three PH-containing proteins were absent, the remaining TORC2 subunits were PM-bound. Revealingly, Avo3 localized to the PM independent of both Avo1 and Tor2, whereas both Tor2 and Avo1 required Avo3 for their PM anchoring. Our findings provide new mechanistic information about TORC2 and pinpoint Avo3 as pivotal for TORC2 PM localization and assembly in vivo.
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Affiliation(s)
- Maria Nieves Martinez Marshall
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Anita Emmerstorfer-Augustin
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kristin L Leskoske
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Lydia H Zhang
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Biyun Li
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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18
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Mioka T, Fujimura-Kamada K, Mizugaki N, Kishimoto T, Sano T, Nunome H, Williams DE, Andersen RJ, Tanaka K. Phospholipid flippases and Sfk1p, a novel regulator of phospholipid asymmetry, contribute to low permeability of the plasma membrane. Mol Biol Cell 2018. [PMID: 29540528 PMCID: PMC5935070 DOI: 10.1091/mbc.e17-04-0217] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Phospholipid flippase (type 4 P-type ATPase) plays a major role in the generation of phospholipid asymmetry in eukaryotic cell membranes. Loss of Lem3p-Dnf1/2p flippases leads to the exposure of phosphatidylserine (PS) and phosphatidylethanolamine (PE) on the cell surface in yeast, resulting in sensitivity to PS- or PE-binding peptides. We isolated Sfk1p, a conserved membrane protein in the TMEM150/FRAG1/DRAM family, as a multicopy suppressor of this sensitivity. Overexpression of SFK1 decreased PS/PE exposure in lem3Δ mutant cells. Consistent with this, lem3Δ sfk1Δ double mutant cells exposed more PS/PE than the lem3Δ mutant. Sfk1p was previously implicated in the regulation of the phosphatidylinositol-4 kinase Stt4p, but the effect of Sfk1p on PS/PE exposure in lem3Δ was independent of Stt4p. Surprisingly, Sfk1p did not facilitate phospholipid flipping but instead repressed it, even under ATP-depleted conditions. We propose that Sfk1p negatively regulates transbilayer movement of phospholipids irrespective of directions. In addition, we showed that the permeability of the plasma membrane was dramatically elevated in the lem3Δ sfk1Δ double mutant in comparison with the corresponding single mutants. Interestingly, total ergosterol was decreased in the lem3Δ sfk1Δ mutant. Our results suggest that phospholipid asymmetry is required for the maintenance of low plasma membrane permeability.
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Affiliation(s)
- Tetsuo Mioka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Konomi Fujimura-Kamada
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Nahiro Mizugaki
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takamitsu Sano
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Hitoshi Nunome
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - David E Williams
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Raymond J Andersen
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Kazuma Tanaka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
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19
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Yamamoto W, Wada S, Nagano M, Aoshima K, Siekhaus DE, Toshima JY, Toshima J. Distinct roles for plasma membrane PtdIns(4)P and PtdIns(4,5)P 2 during receptor-mediated endocytosis in yeast. J Cell Sci 2018; 131:jcs.207696. [PMID: 29192062 DOI: 10.1242/jcs.207696] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 11/14/2017] [Indexed: 01/15/2023] Open
Abstract
Clathrin-mediated endocytosis requires the coordinated assembly of various endocytic proteins and lipids at the plasma membrane. Accumulating evidence demonstrates a crucial role for phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] in endocytosis but specific roles for phosphatidylinositol-4-phosphate [PtdIns(4)P], other than as the biosynthetic precursor of PtdIns(4,5)P2, have not been clarified. In this study we investigated the roles of PtdIns(4)P and PtdIns(4,5)P2 in receptor-mediated endocytosis through the construction of temperature-sensitive (ts) mutants for the phosphatidylinositol 4-kinases (PI4-kinases) Stt4p and Pik1p and the 1-phosphatidylinositol-4-phosphate 5-kinase [PtdIns(4) 5-kinase] Mss4p. Quantitative analyses of endocytosis revealed that both the stt4tspik1ts and mss4ts mutants have a severe defect in endocytic internalization. Live-cell imaging of endocytic protein dynamics in stt4tspik1ts and mss4ts mutants revealed that PtdIns(4)P is required for the recruitment of the α-factor receptor Ste2p to clathrin-coated pits, whereas PtdIns(4,5)P2 is required for membrane internalization. We also found that the localization to endocytic sites of the ENTH/ANTH domain-bearing clathrin adaptors, Ent1p, Ent2p, Yap1801p and Yap1802p, is significantly impaired in the stt4tspik1ts mutant but not in the mss4ts mutant. These results suggest distinct roles in successive steps for PtdIns(4)P and PtdIns(4,5)P2 during receptor-mediated endocytosis.
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Affiliation(s)
- Wataru Yamamoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Suguru Wada
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kaito Aoshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Junko Y Toshima
- School of Health Science, Tokyo University of Technology, 5-23-22 Nishikamata, Ota-ku, Tokyo 144-8535, Japan
| | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
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20
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Khadka B, Gupta RS. Identification of a conserved 8 aa insert in the PIP5K protein in the Saccharomycetaceae family of fungi and the molecular dynamics simulations and structural analysis to investigate its potential functional role. Proteins 2017; 85:1454-1467. [PMID: 28407364 DOI: 10.1002/prot.25306] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/29/2022]
Abstract
Homologs of the phosphatidylinositol-4-phosphate-5-kinase (PIP5K), which controls a multitude of essential cellular functions, contain a 8 aa insert in a conserved region that is specific for the Saccharomycetaceae family of fungi. Using structures of human PIP4K proteins as templates, structural models were generated of the Saccharomyces cerevisiae and human PIP5K proteins. In the modeled S. cerevisiae PIP5K, the 8 aa insert forms a surface exposed loop, present on the same face of the protein as the activation loop of the kinase domain. Electrostatic potential analysis indicates that the residues from 8 aa conserved loop form a highly positively charged surface patch, which through electrostatic interaction with the anionic portions of phospholipid head groups, is expected to play a role in the membrane interaction of the yeast PIP5K. To unravel this prediction, molecular dynamics (MD) simulations were carried out to examine the binding interaction of PIP5K, either containing or lacking the conserved signature insert, with two different membrane lipid bilayers. The results from MD studies provide insights concerning the mechanistic of interaction of PIP5K with lipid bilayer, and support the contention that the identified 8 aa conserved insert in fungal PIP5K plays an important role in the binding of this protein with membrane surface. Proteins 2017; 85:1454-1467. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Bijendra Khadka
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada, L8N 3Z5
| | - Radhey S Gupta
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada, L8N 3Z5
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21
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Hatakeyama R, Kono K, Yoshida S. Ypk1 and Ypk2 kinases maintain Rho1 at the plasma membrane by flippase-dependent lipid remodeling after membrane stresses. J Cell Sci 2017; 130:1169-1178. [PMID: 28167678 DOI: 10.1242/jcs.198382] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/01/2017] [Indexed: 01/15/2023] Open
Abstract
The plasma membrane (PM) is frequently challenged by mechanical stresses. In budding yeast, TORC2-Ypk1/Ypk2 kinase cascade plays a crucial role in PM stress responses by reorganizing the actin cytoskeleton via Rho1 GTPase. However, the molecular mechanism by which TORC2-Ypk1/Ypk2 regulates Rho1 is not well defined. Here, we found that Ypk1/Ypk2 maintain PM localization of Rho1 under PM stress via spatial reorganization of the lipids including phosphatidylserine. Genetic evidence suggests that this process is mediated by the Lem3-containing lipid flippase. We propose that lipid remodeling mediated by the TORC2-Ypk1/Ypk2-Lem3 axis is a backup mechanism for PM anchoring of Rho1 after PM stress-induced acute degradation of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], which is responsible for Rho1 localization under normal conditions. Since all the signaling molecules studied here are conserved in higher eukaryotes, our findings might represent a general mechanism to cope with PM stress.
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Affiliation(s)
- Riko Hatakeyama
- Department of Biology and Rosenstiel Basic Biomedical Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA .,Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Keiko Kono
- Department of Cell Biology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
| | - Satoshi Yoshida
- Department of Biology and Rosenstiel Basic Biomedical Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA .,Gunma Initiative for Advanced Research (GIAR), Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan.,Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan
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22
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Nie WC, He F, Yuan SM, Jia ZW, Wang RR, Gao XD. Roles of an N-terminal coiled-coil-containing domain in the localization and function of Bem3, a Rho GTPase-activating protein in budding yeast. Fungal Genet Biol 2017; 99:40-51. [PMID: 28064039 DOI: 10.1016/j.fgb.2016.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/28/2016] [Accepted: 12/29/2016] [Indexed: 12/26/2022]
Abstract
GTPase-activating proteins (GAPs) play critical roles in the spatial and temporal control of small GTPases. The budding yeast Bem3 is a GAP for Cdc42, a Rho GTPase crucial for actin and septin organization. Bem3 localizes to the sites of polarized growth. However, the amino acid sequence determinants mediating recruitment of Bem3 to its physiological sites of action and those important for Bem3 function are not clear. Here, we show that Bem3's localization is guided by two distinct targeting regions-the PX-PH-domain-containing TD1 and the coiled-coil-containing TD2. TD2 localization is largely mediated by its interaction with the polarisome component Epo1 via heterotypic coiled-coil interaction. This finding reveals a novel role for the polarisome in linking Bem3 to its functional target, Cdc42. We also show that the coiled-coil domain of Bem3 interacts homotypically and this interaction is important for the regulation of Cdc42 by Bem3. Moreover, we show that overexpression of a longer version of the TD2 domain disrupts septin-ring assembly in a RhoGAP-independent manner, suggesting that TD2 may be capable of interacting with proteins implicated in septin-ring assembly. Furthermore, we show that the longer version of TD2 interacts with Kss1, a MAPK involved in filamentous growth. Kss1 is reported to localize mainly in the nucleus. We find that Kss1 also localizes to the sites of polarized growth and Bem3 interacts with Kss1 at the septin-ring assembly site. Our study provides new insights in Bem3's localization and function.
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Affiliation(s)
- Wen-Chao Nie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Fei He
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Si-Min Yuan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhi-Wen Jia
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Rui-Rui Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiang-Dong Gao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China; Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Wuhan, China.
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Ting YH, Lu TJ, Johnson AW, Shie JT, Chen BR, Kumar S S, Lo KY. Bcp1 Is the Nuclear Chaperone of Rpl23 in Saccharomyces cerevisiae. J Biol Chem 2016; 292:585-596. [PMID: 27913624 DOI: 10.1074/jbc.m116.747634] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 11/21/2016] [Indexed: 12/18/2022] Open
Abstract
Eukaryotic ribosomes are composed of rRNAs and ribosomal proteins. Ribosomal proteins are translated in the cytoplasm and imported into the nucleus for assembly with the rRNAs. It has been shown that chaperones or karyopherins responsible for import can maintain the stability of ribosomal proteins by neutralizing unfavorable positive charges and thus facilitate their transports. Among 79 ribosomal proteins in yeast, only a few are identified with specific chaperones. Besides the classic role in maintaining protein stability, chaperones have additional roles in transport, chaperoning the assembly site, and dissociation of ribosomal proteins from karyopherins. Bcp1 has been shown to be necessary for the export of Mss4, a phosphatidylinositol 4-phosphate 5-kinase, and required for ribosome biogenesis. However, its specific function in ribosome biogenesis has not been described. Here, we show that Bcp1 dissociates Rpl23 from the karyopherins and associates with Rpl23 afterward. Loss of Bcp1 causes instability of Rpl23 and deficiency of 60S subunits. In summary, Bcp1 is a novel 60S biogenesis factor via chaperoning Rpl23 in the nucleus.
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Affiliation(s)
- Ya-Han Ting
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Ting-Jun Lu
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Arlen W Johnson
- the Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, and
| | - Jing-Ting Shie
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Bo-Ru Chen
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Suresh Kumar S
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.,the Department of Medical Microbiology and Parasitology, Universiti Putra Malaysia, 43400 Selangor, Malaysia
| | - Kai-Yin Lo
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan,
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24
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Requirement of Phosphoinositides Containing Stearic Acid To Control Cell Polarity. Mol Cell Biol 2015; 36:765-80. [PMID: 26711260 DOI: 10.1128/mcb.00843-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/14/2015] [Indexed: 02/04/2023] Open
Abstract
Phosphoinositides (PIPs) are present in very small amounts but are essential for cell signaling, morphogenesis, and polarity. By mass spectrometry, we demonstrated that some PIPs with stearic acyl chains were strongly disturbed in a psi1Δ Saccharomyces cerevisiae yeast strain deficient in the specific incorporation of a stearoyl chain at the sn-1 position of phosphatidylinositol. The absence of PIPs containing stearic acid induced disturbances in intracellular trafficking, although the total amount of PIPs was not diminished. Changes in PIPs also induced alterations in the budding pattern and defects in actin cytoskeleton organization (cables and patches). Moreover, when the PSI1 gene was impaired, a high proportion of cells with bipolar cortical actin patches that occurred concomitantly with the bipolar localization of Cdc42p was specifically found among diploid cells. This bipolar cortical actin phenotype, never previously described, was also detected in a bud9Δ/bud9Δ strain. Very interestingly, overexpression of PSI1 reversed this phenotype.
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25
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Zhu S, Dai J, Liu H, Cong X, Chen Y, Wu Y, Hu H, Heng BC, Ouyang HW, Zhou Y. Down-regulation of Rac GTPase-activating protein OCRL1 causes aberrant activation of Rac1 in osteoarthritis development. Arthritis Rheumatol 2015; 67:2154-63. [PMID: 25917196 DOI: 10.1002/art.39174] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 04/21/2015] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Chondrocyte hypertrophy and mineralization are considered to be important pathologic factors in osteoarthritis (OA). We previously reported that Rac1 was aberrantly activated to promote chondrocyte hypertrophy, mineralization, and expression of matrix metalloproteinase 13 and ADAMTS in OA. However, the underlying mechanism of aberrant Rac1 activation in OA is unclear. The present study was undertaken to identify the specific molecular regulator controlling Rac1 activity in OA, as well as to investigate its function in chondrocyte hypertrophy, mineralization, and OA development. METHODS Expression levels of 28 upstream regulators of Rac1 activity, including 8 GTPase-activating proteins (GAPs) and 20 guanine nucleotide exchange factors, in OA and normal cartilage were assessed by quantitative polymerase chain reaction. Chondrocytes were transduced with lentiviral vectors encoding OCRL1, GAP, non-GAP, CA-Rac1, and DN-Rac1, either alone or in combination. Alkaline phosphatase staining was used as a marker of chondrocyte hypertrophy. Rac1 activity was analyzed by pulldown assay. Finally, OA was established in mice by surgical transection of the anterior cruciate ligament and cutting of the medial meniscus. The mice were injected intraarticularly with OCRL1-encoding lentivirus, and whole joints were assessed histologically 6 weeks after surgery. RESULTS OCRL1 was abundantly expressed in normal cartilage and was the only significantly down-regulated RacGAP in OA cartilage. Overexpression of OCRL1 inhibited interleukin-1β-induced Rac1 activity, chondrocyte hypertrophy, and expression of hypertrophy-related genes. Conversely, knockdown of OCRL1 elevated Rac1 activity and promoted chondrocyte hypertrophy and mineralization. Further, OCRL1 modulated Rac1 activity via its GAP domain. Finally, intraarticular injection of OCRL1-encoding lentivirus protected against destruction and degeneration of cartilage in the mouse OA model. CONCLUSION OCRL1 acts as a RacGAP in cartilage to impede chondrocyte hypertrophy and OA development through modulating Rac1 activity. This regulatory pathway might provide potential targets for the development of new therapies for OA.
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Affiliation(s)
- Shouan Zhu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Dai
- Zhejiang University School of Medicine, Hangzhou, China
| | - Huanhuan Liu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoxia Cong
- Zhejiang University School of Medicine, Hangzhou, China
| | - Yishan Chen
- Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Wu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Hu Hu
- Zhejiang University School of Medicine, Hangzhou, China
| | | | - Hong Wei Ouyang
- Zhejiang University School of Medicine and The First Affiliated Hospital, Hangzhou, China
| | - Yiting Zhou
- Zhejiang University School of Medicine, Hangzhou, China
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Kabeche R, Madrid M, Cansado J, Moseley JB. Eisosomes Regulate Phosphatidylinositol 4,5-Bisphosphate (PI(4,5)P2) Cortical Clusters and Mitogen-activated Protein (MAP) Kinase Signaling upon Osmotic Stress. J Biol Chem 2015; 290:25960-73. [PMID: 26359496 DOI: 10.1074/jbc.m115.674192] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 01/22/2023] Open
Abstract
Eisosomes are multiprotein structures that generate linear invaginations at the plasma membrane of yeast cells. The core component of eisosomes, the BAR domain protein Pil1, generates these invaginations through direct binding to lipids including phosphoinositides. Eisosomes promote hydrolysis of phosphatidylinositol 4,5 bisphosphate (PI(4,5)P2) by functioning with synaptojanin, but the cellular processes regulated by this pathway have been unknown. Here, we found that PI(4,5)P2 regulation by eisosomes inhibits the cell integrity pathway, a conserved MAPK signal transduction cascade. This pathway is activated by multiple environmental conditions including osmotic stress in the fission yeast Schizosaccharomyces pombe. Activation of the MAPK Pmk1 was impaired by mutations in the phosphatidylinositol (PI) 5-kinase Its3, but this defect was suppressed by removal of eisosomes. Using fluorescent biosensors, we found that osmotic stress induced the formation of PI(4,5)P2 clusters that were spatially organized by eisosomes in both fission yeast and budding yeast cells. These cortical clusters contained the PI 5-kinase Its3 and did not assemble in the its3-1 mutant. The GTPase Rho2, an upstream activator of Pmk1, also co-localized with PI(4,5)P2 clusters under osmotic stress, providing a molecular link between these novel clusters and MAPK activation. Our findings have revealed that eisosomes regulate activation of MAPK signal transduction through the organization of cortical lipid-based microdomains.
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Affiliation(s)
- Ruth Kabeche
- From the Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755 and
| | - Marisa Madrid
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - José Cansado
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - James B Moseley
- From the Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755 and
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Fernández-Acero T, Rodríguez-Escudero I, Molina M, Cid VJ. The yeast cell wall integrity pathway signals from recycling endosomes upon elimination of phosphatidylinositol (4,5)-bisphosphate by mammalian phosphatidylinositol 3-kinase. Cell Signal 2015; 27:2272-84. [PMID: 26261079 DOI: 10.1016/j.cellsig.2015.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/05/2015] [Indexed: 11/29/2022]
Abstract
Phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P(2)] is essential for recognition of the plasma membrane inner leaf by protein complexes. We expressed mammalian class I phosphoinositide 3-kinase (PI3K) in Saccharomyces cerevisiae to eliminate PtdIns(4,5)P(2) by its conversion into PtdIns(3,4,5)P(3), a lipid naturally missing in this yeast. This led to loss of actin function and endocytosis defects, causing a blockage in polarized secretion. Also, the cell wall integrity (CWI) mitogen-activated protein kinase (MAPK) pathway was activated, triggering a typical transcriptional response. In the absence of PtdIns(4,5)P(2) at the plasma membrane, the Pkc1 protein kinase upstream the CWI MAPK module localized to post-Golgi endosomes marked by SNARE Snc1 and Rab GTPases Ypt31 and Ypt32. Other components at the head of the pathway, like the mechanosensor Wsc1, the GTPase Rho1 and its activator the GDP/GTP exchange factor Rom2, co-localized with Pkc1 in these compartments. Chemical inhibition of PI3K proved that both CWI activation and Pkc1 relocation to endosomes are reversible. These results suggest that the CWI pathway is able to respond to loss of plasma membrane identity from recycling endosomes.
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Affiliation(s)
- Teresa Fernández-Acero
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - Isabel Rodríguez-Escudero
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - María Molina
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain.
| | - Víctor J Cid
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
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28
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Control of Plasma Membrane Permeability by ABC Transporters. EUKARYOTIC CELL 2015; 14:442-53. [PMID: 25724885 DOI: 10.1128/ec.00021-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/19/2015] [Indexed: 12/13/2022]
Abstract
ATP-binding cassette transporters Pdr5 and Yor1 from Saccharomyces cerevisiae control the asymmetric distribution of phospholipids across the plasma membrane as well as serving as ATP-dependent drug efflux pumps. Mutant strains lacking these transporter proteins were found to exhibit very different resistance phenotypes to two inhibitors of sphingolipid biosynthesis that act either late (aureobasidin A [AbA]) or early (myriocin [Myr]) in the pathway leading to production of these important plasma membrane lipids. These pdr5Δ yor1 strains were highly AbA resistant but extremely sensitive to Myr. We provide evidence that these phenotypic changes are likely due to modulation of the plasma membrane flippase complexes, Dnf1/Lem3 and Dnf2/Lem3. Flippases act to move phospholipids from the outer to the inner leaflet of the plasma membrane. Genetic analyses indicate that lem3Δ mutant strains are highly AbA sensitive and Myr resistant. These phenotypes are fully epistatic to those seen in pdr5Δ yor1 strains. Direct analysis of AbA-induced signaling demonstrated that loss of Pdr5 and Yor1 inhibited the AbA-triggered phosphorylation of the AGC kinase Ypk1 and its substrate Orm1. Microarray experiments found that a pdr5Δ yor1 strain induced a Pdr1-dependent induction of the entire Pdr regulon. Our data support the view that Pdr5/Yor1 negatively regulate flippase function and activity of the nuclear Pdr1 transcription factor. Together, these data argue that the interaction of the ABC transporters Pdr5 and Yor1 with the Lem3-dependent flippases regulates permeability of AbA via control of plasma membrane protein function as seen for the high-affinity tryptophan permease Tat2.
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29
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Cortesio CL, Lewellyn EB, Drubin DG. Control of lipid organization and actin assembly during clathrin-mediated endocytosis by the cytoplasmic tail of the rhomboid protein Rbd2. Mol Biol Cell 2015; 26:1509-22. [PMID: 25694450 PMCID: PMC4395130 DOI: 10.1091/mbc.e14-11-1540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/09/2015] [Indexed: 12/13/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) requires precise regulation of the actin cytoskeleton. The yeast rhomboid protein Rbd2 controls the timing of actin polymerization during CME through its cytoplasmic tail and a PtdIns(4,5)P2-dependent mechanism. Clathrin-mediated endocytosis (CME) is facilitated by a precisely regulated burst of actin assembly. PtdIns(4,5)P2 is an important signaling lipid with conserved roles in CME and actin assembly regulation. Rhomboid family multipass transmembrane proteins regulate diverse cellular processes; however, rhomboid-mediated CME regulation has not been described. We report that yeast lacking the rhomboid protein Rbd2 exhibit accelerated endocytic-site dynamics and premature actin assembly during CME through a PtdIns(4,5)P2-dependent mechanism. Combined genetic and biochemical studies showed that the cytoplasmic tail of Rbd2 binds directly to PtdIns(4,5)P2 and is sufficient for Rbd2's role in actin regulation. Analysis of an Rbd2 mutant with diminished PtdIns(4,5)P2-binding capacity indicates that this interaction is necessary for the temporal regulation of actin assembly during CME. The cytoplasmic tail of Rbd2 appears to modulate PtdIns(4,5)P2 distribution on the cell cortex. The syndapin-like F-BAR protein Bzz1 functions in a pathway with Rbd2 to control the timing of type 1 myosin recruitment and actin polymerization onset during CME. This work reveals that the previously unstudied rhomboid protein Rbd2 functions in vivo at the nexus of three highly conserved processes: lipid regulation, endocytic regulation, and cytoskeletal function.
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Affiliation(s)
- Christa L Cortesio
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Eric B Lewellyn
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - David G Drubin
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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30
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Qadota H, Benian GM. An approach for exploring interaction between two proteins in vivo. Front Physiol 2014; 5:162. [PMID: 24808865 PMCID: PMC4010775 DOI: 10.3389/fphys.2014.00162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 04/08/2014] [Indexed: 01/13/2023] Open
Abstract
We describe a strategy for exploring the function of protein-protein interactions in striated muscle in vivo. We describe our experience using this strategy to study the interaction of UNC-112 (kindlin) with PAT-4 (integrin linked kinase). Random mutagenesis is used to generate a collection of mutants that are screened for lack of binding or gain of binding using a yeast 2-hybrid assay. The mutant proteins are then expressed in transgenic C. elegans to determine their ability to localize in the sarcomere. We emphasize two advantages of this strategy: (1) for studying the interaction of protein A with protein B, when protein A can interact with multiple proteins, and (2) it explores the function of an interaction rather than the absence of, or reduced level of, a protein as can be obtained with null mutants or knockdown by RNAi. We propose that this method can be generalized for studying the meaning of a protein-protein interaction in muscle for any system in which transgenic animals can be generated and their muscles can be imaged.
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Affiliation(s)
- Hiroshi Qadota
- Department of Pathology, Emory University Atlanta, GA, USA
| | - Guy M Benian
- Department of Pathology, Emory University Atlanta, GA, USA
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31
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Martin SG, Arkowitz RA. Cell polarization in budding and fission yeasts. FEMS Microbiol Rev 2014; 38:228-53. [DOI: 10.1111/1574-6976.12055] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 11/13/2013] [Accepted: 12/03/2013] [Indexed: 11/30/2022] Open
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Ischebeck T, Werner S, Krishnamoorthy P, Lerche J, Meijón M, Stenzel I, Löfke C, Wiessner T, Im YJ, Perera IY, Iven T, Feussner I, Busch W, Boss WF, Teichmann T, Hause B, Persson S, Heilmann I. Phosphatidylinositol 4,5-bisphosphate influences PIN polarization by controlling clathrin-mediated membrane trafficking in Arabidopsis. THE PLANT CELL 2013; 25:4894-911. [PMID: 24326589 PMCID: PMC3903994 DOI: 10.1105/tpc.113.116582] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/22/2013] [Accepted: 10/15/2013] [Indexed: 05/19/2023]
Abstract
The functions of the minor phospholipid phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] during vegetative plant growth remain obscure. Here, we targeted two related phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) PIP5K1 and PIP5K2, which are expressed ubiquitously in Arabidopsis thaliana. A pip5k1 pip5k2 double mutant with reduced PtdIns(4,5)P2 levels showed dwarf stature and phenotypes suggesting defects in auxin distribution. The roots of the pip5k1 pip5k2 double mutant had normal auxin levels but reduced auxin transport and altered distribution. Fluorescence-tagged auxin efflux carriers PIN-FORMED (PIN1)-green fluorescent protein (GFP) and PIN2-GFP displayed abnormal, partially apolar distribution. Furthermore, fewer brefeldin A-induced endosomal bodies decorated by PIN1-GFP or PIN2-GFP formed in pip5k1 pip5k2 mutants. Inducible overexpressor lines for PIP5K1 or PIP5K2 also exhibited phenotypes indicating misregulation of auxin-dependent processes, and immunolocalization showed reduced membrane association of PIN1 and PIN2. PIN cycling and polarization require clathrin-mediated endocytosis and labeled clathrin light chain also displayed altered localization patterns in the pip5k1 pip5k2 double mutant, consistent with a role for PtdIns(4,5)P2 in the regulation of clathrin-mediated endocytosis. Further biochemical tests on subcellular fractions enriched for clathrin-coated vesicles (CCVs) indicated that pip5k1 and pip5k2 mutants have reduced CCV-associated PI4P 5-kinase activity. Together, the data indicate an important role for PtdIns(4,5)P2 in the control of clathrin dynamics and in auxin distribution in Arabidopsis.
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Affiliation(s)
- Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Stephanie Werner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | | | - Jennifer Lerche
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Mónica Meijón
- Gregor-Mendel-Institute for Molecular Plant Biology, 1030 Vienna, Austria
| | - Irene Stenzel
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Christian Löfke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Schwann-Schleiden Centre, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Theresa Wiessner
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Yang Ju Im
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Imara Y. Perera
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Tim Iven
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Wolfgang Busch
- Gregor-Mendel-Institute for Molecular Plant Biology, 1030 Vienna, Austria
| | - Wendy F. Boss
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Thomas Teichmann
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Schwann-Schleiden Centre, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Bettina Hause
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Staffan Persson
- Max-Planck-Institute for Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Ingo Heilmann
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Address correspondence to
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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34
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Guillas I, Vernay A, Vitagliano JJ, Arkowitz RA. Phosphatidylinositol 4,5-bisphosphate is required for invasive growth in Saccharomyces cerevisiae. J Cell Sci 2013; 126:3602-14. [PMID: 23781030 DOI: 10.1242/jcs.122606] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Phosphatidylinositol phosphates are important regulators of processes such as the cytoskeleton organization, membrane trafficking and gene transcription, which are all crucial for polarized cell growth. In particular, phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] has essential roles in polarized growth as well as in cellular responses to stress. In the yeast Saccharomyces cerevisiae, the sole phosphatidylinositol-4-phosphate 5-kinase (PI4P5K) Mss4p is essential for generating plasma membrane PtdIns(4,5)P2. Here, we show that Mss4p is required for yeast invasive growth in low-nutrient conditions. We isolated specific mss4 mutants that were defective in cell elongation, induction of the Flo11p flocculin, adhesion and cell wall integrity. We show that mss4-f12 cells have reduced plasma membrane PtdIns(4,5)P2 levels as well as a defect in its polarized distribution, yet Mss4-f12p is catalytically active in vitro. In addition, the Mss4-f12 protein was defective in localizing to the plasma membrane. Furthermore, addition of cAMP, but not an activated MAPKKK allele, partially restored the invasive growth defect of mss4-f12 cells. Taken together, our results indicate that plasma membrane PtdIns(4,5)P2 is crucial for yeast invasive growth and suggest that this phospholipid functions upstream of the cAMP-dependent protein kinase A signaling pathway.
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Affiliation(s)
- Isabelle Guillas
- Université Nice - Sophia Antipolis, Institute of Biology Valrose, 06108 Nice Cedex 2, France
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35
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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Phosphatidylinositol 5-phosphate 4-kinase (PIP4K) regulates TOR signaling and cell growth during Drosophila development. Proc Natl Acad Sci U S A 2013; 110:5963-8. [PMID: 23530222 DOI: 10.1073/pnas.1219333110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During development, Drosophila larvae undergo a dramatic increase in body mass wherein nutritional and developmental cues are transduced into growth through the activity of complex signaling pathways. Class I phosphoinositide 3-kinases have an established role in this process. In this study we identify Drosophila phosphatidylinositol 5-phosphate 4-kinase (dPIP4K) as a phosphoinositide kinase that regulates growth during larval development. Loss-of-function mutants in dPIP4K show reduced body weight and prolonged larval development, whereas overexpression of dPIP4K results both in an increase in body weight and shortening of larval development. The growth defect associated with dPIP4K loss of function is accompanied by a reduction in the average cell size of larval endoreplicative tissues. Our findings reveal that these phenotypes are underpinned by changes in the signaling input into the target of rapamycin (TOR) signaling complex and changes in the activity of its direct downstream target p70 S6 kinase. Together, these results define dPIP4K activity as a regulator of cell growth and TOR signaling during larval development.
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The essential phosphoinositide kinase MSS-4 is required for polar hyphal morphogenesis, localizing to sites of growth and cell fusion in Neurospora crassa. PLoS One 2012; 7:e51454. [PMID: 23272106 PMCID: PMC3521734 DOI: 10.1371/journal.pone.0051454] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/01/2012] [Indexed: 11/22/2022] Open
Abstract
Fungal hyphae and plant pollen tubes are among the most highly polarized cells known and pose extraordinary requirements on their cell polarity machinery. Cellular morphogenesis is driven through the phospholipid-dependent organization at the apical plasma membrane. We characterized the contribution of phosphoinositides (PIs) in hyphal growth of the filamentous ascomycete Neurospora crassa. MSS-4 is an essential gene and its deletion resulted in spherically growing cells that ultimately lyse. Two conditional mss-4-mutants exhibited altered hyphal morphology and aberrant branching at restrictive conditions that were complemented by expression of wild type MSS-4. Recombinant MSS-4 was characterized as a phosphatidylinositolmonophosphate-kinase phosphorylating phosphatidylinositol 4-phosphate (PtdIns4P) to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). PtdIns3P was also used as a substrate. Sequencing of two conditional mss-4 alleles identified a single substitution of a highly conserved Y750 to N. The biochemical characterization of recombinant protein variants revealed Y750 as critical for PI4P 5-kinase activity of MSS-4 and of plant PI4P 5-kinases. The conditional growth defects of mss-4 mutants were caused by severely reduced activity of MSS-4(Y750N), enabling the formation of only trace amounts of PtdIns(4,5)P2. In N. crassa hyphae, PtdIns(4,5)P2 localized predominantly in the plasma membrane of hyphae and along septa. Fluorescence-tagged MSS-4 formed a subapical collar at hyphal tips, localized to constricting septa and accumulated at contact points of fusing N. crassa germlings, indicating MSS-4 is responsible for the formation of relevant pools of PtdIns(4,5)P2 that control polar and directional growth and septation. N. crassa MSS-4 differs from yeast, plant and mammalian PI4P 5-kinases by containing additional protein domains. The N-terminal domain of N. crassa MSS-4 was required for correct membrane association. The data presented for N. crassa MSS-4 and its roles in hyphal growth are discussed with a comparative perspective on PI-control of polar tip growth in different organismic kingdoms.
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Sun Y, Drubin DG. The functions of anionic phospholipids during clathrin-mediated endocytosis site initiation and vesicle formation. J Cell Sci 2012; 125:6157-65. [PMID: 23097040 DOI: 10.1242/jcs.115741] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anionic phospholipids PI(4,5)P2 and phosphatidylserine (PS) are enriched in the cytosolic leaflet of the plasma membrane where endocytic sites form. In this study, we investigated the roles of PI(4,5)P2 and PS in clathrin-mediated endocytosis (CME) site initiation and vesicle formation in Saccharomyces cerevisiae. Live-cell imaging of endocytic protein dynamics in an mss4(ts) mutant, which has severely reduced PI(4,5)P2 levels, revealed that PI(4,5)P2 is required for endocytic membrane invagination but is less important for endocytic site initiation. We also demonstrated that, in various deletion mutants of genes encoding components of the Rcy1-Ypt31/32 GTPase pathway, endocytic proteins dynamically assemble not only on the plasma membrane but also on intracellular membrane compartments, which are likely derived from early endosomes. In rcy1Δ cells, fluorescent biosensors indicated that PI(4,5)P2 only localized to the plasma membrane while PS localized to both the plasma membrane and intracellular membranes. Furthermore, we found that polarized endocytic patch establishment is defective in the PS-deficient cho1Δ mutant. We propose that PS is important for directing endocytic proteins to the plasma membrane and that PI(4,5)P2 is required to facilitate endocytic membrane invagination.
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Affiliation(s)
- Yidi Sun
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA
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39
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Vernay A, Schaub S, Guillas I, Bassilana M, Arkowitz RA. A steep phosphoinositide bis-phosphate gradient forms during fungal filamentous growth. ACTA ACUST UNITED AC 2012; 198:711-30. [PMID: 22891265 PMCID: PMC3514036 DOI: 10.1083/jcb.201203099] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
A gradient of PI(4,5)P2 formed by phospholipid synthesis, diffusion,
and regulated turnover is crucial for filamentous growth. Membrane lipids have been implicated in many critical cellular processes, yet
little is known about the role of asymmetric lipid distribution in cell
morphogenesis. The phosphoinositide bis-phosphate PI(4,5)P2 is
essential for polarized growth in a range of organisms. Although an asymmetric
distribution of this phospholipid has been observed in some cells, long-range
gradients of PI(4,5)P2 have not been observed. Here, we show that in
the human pathogenic fungus Candida albicans a steep,
long-range gradient of PI(4,5)P2 occurs concomitant with emergence of
the hyphal filament. Both sufficient PI(4)P synthesis and the actin cytoskeleton
are necessary for this steep PI(4,5)P2 gradient. In contrast, neither
microtubules nor asymmetrically localized mRNAs are critical. Our results
indicate that a gradient of PI(4,5)P2, crucial for filamentous
growth, is generated and maintained by the filament tip–localized
PI(4)P-5-kinase Mss4 and clearing of this lipid at the back of the cell.
Furthermore, we propose that slow membrane diffusion of PI(4,5)P2
contributes to the maintenance of such a gradient.
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Affiliation(s)
- Aurélia Vernay
- Institute of Biology Valrose, Université Nice - Sophia Antipolis, 06108 Nice Cedex 2, France
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40
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The dual PH domain protein Opy1 functions as a sensor and modulator of PtdIns(4,5)P₂ synthesis. EMBO J 2012; 31:2882-94. [PMID: 22562153 DOI: 10.1038/emboj.2012.127] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 04/11/2012] [Indexed: 11/09/2022] Open
Abstract
Phosphatidylinositol-4,5-bisphosphate, PtdIns(4,5)P(2), is an essential signalling lipid that regulates key processes such as endocytosis, exocytosis, actin cytoskeletal organization and calcium signalling. Maintaining proper levels of PtdIns(4,5)P(2) at the plasma membrane (PM) is crucial for cell survival and growth. We show that the conserved PtdIns(4)P 5-kinase, Mss4, forms dynamic, oligomeric structures at the PM that we term PIK patches. The dynamic assembly and disassembly of Mss4 PIK patches may provide a mechanism to precisely modulate Mss4 kinase activity, as needed, for localized regulation of PtdIns(4,5)P(2) synthesis. Furthermore, we identify a tandem PH domain-containing protein, Opy1, as a novel Mss4-interacting protein that partially colocalizes with PIK patches. Based upon genetic, cell biological, and biochemical data, we propose that Opy1 functions as a coincidence detector of the Mss4 PtdIns(4)P 5-kinase and PtdIns(4,5)P(2) and serves as a negative regulator of PtdIns(4,5)P(2) synthesis at the PM. Our results also suggest that additional conserved tandem PH domain-containing proteins may play important roles in regulating phosphoinositide signalling.
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Regulation of cell wall biogenesis in Saccharomyces cerevisiae: the cell wall integrity signaling pathway. Genetics 2012; 189:1145-75. [PMID: 22174182 DOI: 10.1534/genetics.111.128264] [Citation(s) in RCA: 612] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to the Rho1 GTPase, which mobilizes a physiologic response through a variety of effectors. Activation of CWI signaling regulates the production of various carbohydrate polymers of the cell wall, as well as their polarized delivery to the site of cell wall remodeling. This review article centers on CWI signaling in Saccharomyces cerevisiae through the cell cycle and in response to cell wall stress. The interface of this signaling pathway with other pathways that contribute to the maintenance of cell wall integrity is also discussed.
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42
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Schuh AL, Audhya A. Phosphoinositide signaling during membrane transport in Saccharomyces cerevisiae. Subcell Biochem 2012; 59:35-63. [PMID: 22374087 DOI: 10.1007/978-94-007-3015-1_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Phosphatidylinositol (PI) is distinct from other phospholipids, possessing a head group that can be modified by phosphorylation at multiple positions to generate unique signaling molecules collectively known as phosphoinositides. The set of kinases and phosphatases that regulate PI metabolism are conserved throughout eukaryotic evolution, and numerous studies have demonstrated that phosphoinositides regulate a diverse spectrum of cellular processes, including vesicle transport, cell proliferation, and cytoskeleton organization. Over the past two decades, nearly all PI derivatives have been shown to interact directly with cellular proteins to affect their localization and/or activity. Additionally, there is growing evidence, which suggests that phosphoinositides may also affect local membrane topology. Here, we focus on the role of phosphoinositides in membrane trafficking and underscore the significant role that yeast has played in the field.
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Affiliation(s)
- Amber L Schuh
- Department of Biomolecular Chemistry, University of Wisconsin-Madison Medical School, 1300 University Avenue, WI, 53706, Madison, USA
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43
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Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP(2)) is a membrane bound lipid molecule with capabilities to affect a wide array of signaling pathways to regulate very different cellular processes. PIP(2) is used as a precursor to generate the second messengers PIP(3), DAG and IP(3), indispensable molecules for signaling events generated by membrane receptors. However, PIP(2) can also directly regulate a vast array of proteins and is emerging as a crucial messenger with the potential to distinctly modulate biological processes critical for both normal and pathogenic cell physiology. PIP(2) directly associates with effector proteins via unique phosphoinositide binding domains, altering their localization and/or enzymatic activity. The spatial and temporal generation of PIP(2) synthesized by the phosphatidylinositol phosphate kinases (PIPKs) tightly regulates the activation of receptor signaling pathways, endocytosis and vesicle trafficking, cell polarity, focal adhesion dynamics, actin assembly and 3' mRNA processing. Here we discuss our current understanding of PIPKs in the regulation of cellular processes from the plasma membrane to the nucleus.
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44
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The mycelial response of the white-rot fungus, Schizophyllum commune to the biocontrol agent, Trichoderma viride. Fungal Biol 2011; 116:332-41. [PMID: 22289778 DOI: 10.1016/j.funbio.2011.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 12/13/2011] [Accepted: 12/14/2011] [Indexed: 11/22/2022]
Abstract
In this study, agar plate interaction between Schizophyllum commune and Trichoderma viride was investigated to characterise the physiological responses occurring during interspecific mycelial combat. The metabolite profiles and morphological changes in both fungi paired on agar were studied relative to the modulation of phenoloxidase activity in S. commune. The calcium ionophore A23187 was incorporated in self-paired cultures of S. commune to explore possible involvement of calcium influx in the response of S. commune to T. viride. The levels of lipid peroxides and protein carbonyls in the confronted mycelia of S. commune were also measured. Contact with T. viride induced pigmentation and cell wall hydrolysis in S. commune with concomitant increase in phenoloxidase activity, rise in the levels of oxidative stress indicators and increased levels of phenolic compounds, antioxidant γ-amino butyric acid, and pyridoxine and osmo-protective sugar alcohols. Calcium ionophore mimicked the pigmentation in the T. viride-confronted mycelia of S. commune, implicating calcium influx in the response to T. viride. The changes in S. commune are indicative of targeted responses to osmotic and oxidative stresses and phenoloxidase-mediated detoxification of noxious compounds in the contact interface with T. viride, which may confer resistance in natural environments.
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45
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Weinberg J, Drubin DG. Clathrin-mediated endocytosis in budding yeast. Trends Cell Biol 2011; 22:1-13. [PMID: 22018597 DOI: 10.1016/j.tcb.2011.09.001] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/26/2011] [Accepted: 09/01/2011] [Indexed: 02/04/2023]
Abstract
Clathrin-mediated endocytosis in the budding yeast Saccharomyces cerevisiae involves the ordered recruitment, activity and disassembly of nearly 60 proteins at distinct sites on the plasma membrane. Two-color live-cell fluorescence microscopy has proven to be invaluable for in vivo analysis of endocytic proteins: identifying new components, determining the order of protein arrival and dissociation, and revealing even very subtle mutant phenotypes. Yeast genetics and functional genomics facilitate identification of complex interaction networks between endocytic proteins and their regulators. Quantitative datasets produced by these various analyses have made theoretical modeling possible. Here, we discuss recent findings on budding yeast endocytosis that have advanced our knowledge of how -60 endocytic proteins are recruited, perform their functions, are regulated by lipid and protein modifications, and are disassembled, all with remarkable regularity.
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Affiliation(s)
- Jasper Weinberg
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA
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46
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Murphy ER, Boxberger J, Colvin R, Lee SJ, Zahn G, Loor F, Kim K. Pil1, an eisosome organizer, plays an important role in the recruitment of synaptojanins and amphiphysins to facilitate receptor-mediated endocytosis in yeast. Eur J Cell Biol 2011; 90:825-33. [PMID: 21872358 DOI: 10.1016/j.ejcb.2011.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/25/2011] [Accepted: 06/11/2011] [Indexed: 11/17/2022] Open
Abstract
The eisosome protein Pil1 is known to be implicated in the endocytosis of Ste3, but the precise biological function of it during endocytosis is poorly understood. Here, we present data to reveal Pil1's role in receptor-mediated endocytosis. Using live cell imaging, we show that endocytic patches carrying Abp1 and Las17 persisted much longer in PIL1-deficient cells. The loss of Pil1 also greatly affected both the scission efficiency and the frequency of formation of endocytic sites carrying Rvs161- and Rvs167-GFP. Furthermore, the mistargeting of the synaptojanins, Sjl1 and Sjl2, to the cytoplasm in pil1Δ cells suggests that Pil1 is required for the proper recruitment of the synaptojanins to endocytic sites. A severe motility defect of Abp1-GFP during its internalization in a codeletant of PIL1 and SJL2 indicates a functional interplay between them in endocytosis. Together, these results establish that Pil1 is involved in the recruitment of endocytic proteins to optimize endocytosis.
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Affiliation(s)
- Erin R Murphy
- Department of Biology, Missouri State University, 901 South National Ave., Springfield, MO 65897, USA
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47
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Kamble C, Jain S, Murphy E, Kim K. Requirements of Slm proteins for proper eisosome organization, endocytic trafficking and recycling in the yeast Saccharomyces cerevisiae. J Biosci 2011; 36:79-96. [PMID: 21451250 DOI: 10.1007/s12038-011-9018-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Eisosomes are large immobile assemblies at the cortex of a cell under the membrane compartment of Can1 (MCC) in yeast. Slm1 has recently been identified as an MCC component that acts downstream of Mss4 in a pathway that regulates actin cytoskeleton organization in response to stress. In this study, we showed that inactivation of Slm proteins disrupts proper localization of the primary eisosome marker Pil1, providing evidence that Slm proteins play a role in eisosome organization. Furthermore, we found that slm ts mutant cells exhibit actin defects in both the ability to polarize cortical F-actin and the formation of cytoplasmic actin cables even at the permissive temperature (30 degrees C). We further demonstrated that the actin defect accounts for the slow traffic of FM4-64- labelled endosome in the cytoplasm, supporting the notion that intact actin is essential for endosome trafficking. However, our real-time microscopic analysis of Abp1-RFP revealed that the actin defect in slm ts cells was not accompanied by a noticeable defect in actin patch internalization during receptor-mediated endocytosis. In addition, we found that slm ts cells displayed impaired membrane recycling and that recycling occurred in an actin-independent manner. Our data provide evidence for the requirement of Slm proteins in eisosome organization and endosome trafficking and recycling.
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Affiliation(s)
- Chitra Kamble
- Department of Biology, Missouri State University, 901 South National Ave, Springfield, MO 65897, USA
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48
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Sammons MR, James ML, Clayton JE, Sladewski TE, Sirotkin V, Lord M. A calmodulin-related light chain from fission yeast that functions with myosin-I and PI 4-kinase. J Cell Sci 2011; 124:2466-77. [PMID: 21693583 DOI: 10.1242/jcs.067850] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fission yeast myosin-I (Myo1p) not only associates with calmodulin, but also employs a second light chain called Cam2p. cam2Δ cells exhibit defects in cell polarity and growth consistent with a loss of Myo1p function. Loss of Cam2p leads to a reduction in Myo1p levels at endocytic patches and a 50% drop in the rates of Myo1p-driven actin filament motility. Thus, Cam2p plays a significant role in Myo1p function. However, further studies indicated the existence of an additional Cam2p-binding partner. Cam2p was still present at cortical patches in myo1Δ cells (or in myo1-IQ2 mutants, which lack an intact Cam2p-binding motif), whereas a cam2 null (cam2Δ) suppressed cytokinesis defects of an essential light chain (ELC) mutant known to be impaired in binding to PI 4-kinase (Pik1p). Binding studies revealed that Cam2p and the ELC compete for Pik1p. Cortical localization of Cam2p in the myo1Δ background relied on its association with Pik1p, whereas overexpression studies indicated that Cam2p, in turn, contributes to Pik1p function. The fact that the Myo1p-associated defects of a cam2Δ mutant are more potent than those of a myo1-IQ2 mutant suggests that myosin light chains can contribute to actomyosin function both directly and indirectly (via phospholipid synthesis at sites of polarized growth).
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Affiliation(s)
- Matthew R Sammons
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA.
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49
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Cappell SD, Dohlman HG. Selective regulation of MAP kinase signaling by an endomembrane phosphatidylinositol 4-kinase. J Biol Chem 2011; 286:14852-60. [PMID: 21388955 DOI: 10.1074/jbc.m110.195073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Multiple MAP kinase pathways share components yet initiate distinct biological processes. Signaling fidelity can be maintained by scaffold proteins and restriction of signaling complexes to discreet subcellular locations. For example, the yeast MAP kinase scaffold Ste5 binds to phospholipids produced at the plasma membrane and promotes selective MAP kinase activation. Here we show that Pik1, a phosphatidylinositol 4-kinase that localizes primarily to the Golgi, also regulates MAP kinase specificity but does so independently of Ste5. Pik1 is required for full activation of the MAP kinases Fus3 and Hog1 and represses activation of Kss1. Further, we show by genetic epistasis analysis that Pik1 likely regulates Ste11 and Ste50, components shared by all three MAP kinase pathways, through their interaction with the scaffold protein Opy2. These findings reveal a new regulator of signaling specificity functioning at endomembranes rather than at the plasma membrane.
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Affiliation(s)
- Steven D Cappell
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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50
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Kinase associated-1 domains drive MARK/PAR1 kinases to membrane targets by binding acidic phospholipids. Cell 2011; 143:966-77. [PMID: 21145462 DOI: 10.1016/j.cell.2010.11.028] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/03/2010] [Accepted: 11/01/2010] [Indexed: 12/26/2022]
Abstract
Phospholipid-binding modules such as PH, C1, and C2 domains play crucial roles in location-dependent regulation of many protein kinases. Here, we identify the KA1 domain (kinase associated-1 domain), found at the C terminus of yeast septin-associated kinases (Kcc4p, Gin4p, and Hsl1p) and human MARK/PAR1 kinases, as a membrane association domain that binds acidic phospholipids. Membrane localization of isolated KA1 domains depends on phosphatidylserine. Using X-ray crystallography, we identified a structurally conserved binding site for anionic phospholipids in KA1 domains from Kcc4p and MARK1. Mutating this site impairs membrane association of both KA1 domains and intact proteins and reveals the importance of phosphatidylserine for bud neck localization of yeast Kcc4p. Our data suggest that KA1 domains contribute to "coincidence detection," allowing kinases to bind other regulators (such as septins) only at the membrane surface. These findings have important implications for understanding MARK/PAR1 kinases, which are implicated in Alzheimer's disease, cancer, and autism.
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