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Shao L, Fingerhut JM, Falk BL, Han H, Maldonado G, Qiao Y, Lee V, Hall E, Chen L, Polevoy G, Hernández G, Lasko P, Brill JA. Eukaryotic translation initiation factor eIF4E-5 is required for spermiogenesis in Drosophila melanogaster. Development 2023; 150:286752. [PMID: 36695474 DOI: 10.1242/dev.200477] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/16/2023] [Indexed: 01/26/2023]
Abstract
Drosophila sperm development is characterized by extensive post-transcriptional regulation whereby thousands of transcripts are preserved for translation during later stages. A key step in translation initiation is the binding of eukaryotic initiation factor 4E (eIF4E) to the 5' mRNA cap. In addition to canonical eIF4E-1, Drosophila has multiple eIF4E paralogs, including four (eIF4E-3, -4, -5, and -7) that are highly expressed in the testis. Among these, only eIF4E-3 has been characterized genetically. Here, using CRISPR/Cas9 mutagenesis, we determined that eIF4E-5 is essential for male fertility. eIF4E-5 protein localizes to the distal ends of elongated spermatid cysts, and eIF4E-5 mutants exhibit defects during post-meiotic stages, including a mild defect in spermatid cyst polarization. eIF4E-5 mutants also have a fully penetrant defect in individualization, resulting in failure to produce mature sperm. Indeed, our data indicate that eIF4E-5 regulates non-apoptotic caspase activity during individualization by promoting local accumulation of the E3 ubiquitin ligase inhibitor Soti. Our results further extend the diversity of non-canonical eIF4Es that carry out distinct spatiotemporal roles during spermatogenesis.
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Affiliation(s)
- Lisa Shao
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Jaclyn M Fingerhut
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
| | - Brook L Falk
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Hong Han
- Department of Biology, McGill University, 3649 Promenade Sir William Osler, Montréal, Quebec, H3G 0B1, Canada
| | - Giovanna Maldonado
- Laboratory of Translation and Cancer, Unit of Biomedical Research on Cancer, Instituto Nacional de Cancerología (INCan), Av San Fernando 22, Mexico City 14080, Mexico
| | - Yuemeng Qiao
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Human Biology Program, University of Toronto, 300 Huron Street, Toronto, Ontario, M5S 3J6, Canada
| | - Vincent Lee
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Elizabeth Hall
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Liang Chen
- Department of Biology, McGill University, 3649 Promenade Sir William Osler, Montréal, Quebec, H3G 0B1, Canada
| | - Gordon Polevoy
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
| | - Greco Hernández
- Laboratory of Translation and Cancer, Unit of Biomedical Research on Cancer, Instituto Nacional de Cancerología (INCan), Av San Fernando 22, Mexico City 14080, Mexico
| | - Paul Lasko
- Department of Biology, McGill University, 3649 Promenade Sir William Osler, Montréal, Quebec, H3G 0B1, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
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2
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Frendo-Cumbo S, Li T, Ammendolia DA, Coyaud E, Laurent EM, Liu Y, Bilan PJ, Polevoy G, Raught B, Brill JA, Klip A, Brumell JH. DCAF7 regulates cell proliferation through IRS1-FOXO1 signaling. iScience 2022; 25:105668. [PMCID: PMC9732383 DOI: 10.1016/j.isci.2022.105668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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3
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Frendo-Cumbo S, Li T, Ammendolia DA, Coyaud E, Laurent EM, Liu Y, Bilan PJ, Polevoy G, Raught B, Brill JA, Klip A, Brumell JH. DCAF7 regulates cell proliferation through IRS1-FOXO1 signaling. iScience 2022; 25:105188. [PMID: 36248734 PMCID: PMC9556925 DOI: 10.1016/j.isci.2022.105188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 07/13/2022] [Accepted: 09/20/2022] [Indexed: 12/13/2022] Open
Abstract
Cell proliferation is dependent on growth factors insulin and IGF1. We sought to identify interactors of IRS1, the most proximal mediator of insulin/IGF1 signaling, that regulate cell proliferation. Using proximity-dependent biotin identification (BioID), we detected 40 proteins displaying proximal interactions with IRS1, including DCAF7 and its interacting partners DYRK1A and DYRK1B. In HepG2 cells, DCAF7 knockdown attenuated cell proliferation by inducing cell cycle arrest at G2. DCAF7 expression was required for insulin-stimulated AKT phosphorylation, and its absence promoted nuclear localization of the transcription factor FOXO1. DCAF7 knockdown induced expression of FOXO1-target genes implicated in G2 cell cycle inhibition, correlating with G2 cell cycle arrest. In Drosophila melanogaster, wing-specific knockdown of DCAF7/wap caused smaller wing size and lower wing cell number; the latter recovered upon double knockdown of wap and dfoxo. We propose that DCAF7 regulates cell proliferation and cell cycle via IRS1-FOXO1 signaling, of relevance to whole organism growth.
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Affiliation(s)
- Scott Frendo-Cumbo
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Taoyingnan Li
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Dustin A. Ammendolia
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - Estelle M.N. Laurent
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - Yuan Liu
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Philip J. Bilan
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Gordon Polevoy
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada,Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Julie A. Brill
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada,Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Amira Klip
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada,Department of Biochemistry, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - John H. Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada,Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada,SickKids IBD Centre, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada,Corresponding author
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4
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Ma CIJ, Yang Y, Kim T, Chen CH, Polevoy G, Vissa M, Burgess J, Brill JA. Correction: An early endosome-derived retrograde trafficking pathway promotes secretory granule maturation. J Cell Biol 2022; 221:213010. [PMID: 35171983 PMCID: PMC8941667 DOI: 10.1083/jcb.20180801712202021c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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5
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Ma CIJ, Yang Y, Kim T, Chen CH, Polevoy G, VIssa M, Burgess J, Brill JA. Correction: An early endosome–derived retrograde trafficking pathway promotes secretory granule maturation. J Biophys Biochem Cytol 2021. [PMID: 33481993 PMCID: PMC7934211 DOI: 10.1083/jcb.20180801701192021c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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6
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Ma CIJ, Yang Y, Kim T, Chen CH, Polevoy G, VIssa M, Burgess J, Brill JA. Correction: An early endosome-derived retrograde trafficking pathway promotes secretory granule maturation. J Cell Biol 2021; 220:211708. [PMID: 33481993 DOI: 10.1084/jcb.20180801701192021c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Ma CIJ, Yang Y, Kim T, Chen CH, Polevoy G, Vissa M, Burgess J, Brill JA. An early endosome-derived retrograde trafficking pathway promotes secretory granule maturation. J Cell Biol 2020; 219:133712. [PMID: 32045479 PMCID: PMC7055004 DOI: 10.1083/jcb.201808017] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/30/2019] [Accepted: 12/20/2019] [Indexed: 02/08/2023] Open
Abstract
Regulated secretion is a fundamental cellular process in which biologically active molecules stored in long-lasting secretory granules (SGs) are secreted in response to external stimuli. Many studies have described mechanisms responsible for biogenesis and secretion of SGs, but how SGs mature remains poorly understood. In a genetic screen, we discovered a large number of endolysosomal trafficking genes required for proper SG maturation, indicating that maturation of SGs might occur in a manner similar to lysosome-related organelles (LROs). CD63, a tetraspanin known to decorate LROs, also decorates SG membranes and facilitates SG maturation. Moreover, CD63-mediated SG maturation requires type II phosphatidylinositol 4 kinase (PI4KII)-dependent early endosomal sorting and accumulation of phosphatidylinositol 4-phosphate (PI4P) on SG membranes. In addition, the PI4P effector Past1 is needed for formation of stable PI4KII-containing endosomal tubules associated with this process. Our results reveal that maturation of post-Golgi-derived SGs requires trafficking via the endosomal system, similar to mechanisms employed by LROs.
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Affiliation(s)
- Cheng-I J Ma
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Yitong Yang
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Taeah Kim
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Human Biology Program, University of Toronto, Toronto, ON, Canada
| | - Chang Hua Chen
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Human Biology Program, University of Toronto, Toronto, ON, Canada
| | - Gordon Polevoy
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Miluska Vissa
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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8
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Del Bel LM, Griffiths N, Wilk R, Wei HC, Blagoveshchenskaya A, Burgess J, Polevoy G, Price JV, Mayinger P, Brill JA. The phosphoinositide phosphatase Sac1 regulates cell shape and microtubule stability in the developing Drosophila eye. Development 2018; 145:dev.151571. [PMID: 29752385 DOI: 10.1242/dev.151571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 04/30/2018] [Indexed: 12/15/2022]
Abstract
Epithelial patterning in the developing Drosophila melanogaster eye requires the Neph1 homolog Roughest (Rst), an immunoglobulin family cell surface adhesion molecule expressed in interommatidial cells (IOCs). Here, using a novel temperature-sensitive (ts) allele, we show that the phosphoinositide phosphatase Sac1 is also required for IOC patterning. Sac1ts mutants have rough eyes and retinal patterning defects that resemble rst mutants. Sac1ts retinas exhibit elevated levels of phosphatidylinositol 4-phosphate (PI4P), consistent with the role of Sac1 as a PI4P phosphatase. Indeed, genetic rescue and interaction experiments reveal that restriction of PI4P levels by Sac1 is crucial for normal eye development. Rst is delivered to the cell surface in Sac1ts mutants. However, Sac1ts mutant IOCs exhibit severe defects in microtubule organization, associated with accumulation of Rst and the exocyst subunit Sec8 in enlarged intracellular vesicles upon cold fixation ex vivo Together, our data reveal a novel requirement for Sac1 in promoting microtubule stability and suggest that Rst trafficking occurs in a microtubule- and exocyst-dependent manner.
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Affiliation(s)
- Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Nigel Griffiths
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Ronit Wilk
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
| | - Ho-Chun Wei
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, South Sciences Building Room 8166, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Anastasia Blagoveshchenskaya
- Division of Nephrology & Hypertension, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd., Portland, Oregon 97239-3098, USA
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Gordon Polevoy
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
| | - James V Price
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Sciences Building Room 8166, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Peter Mayinger
- Division of Nephrology & Hypertension, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd., Portland, Oregon 97239-3098, USA
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
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9
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Burgess J, Del Bel LM, Ma CIJ, Barylko B, Polevoy G, Rollins J, Albanesi JP, Krämer H, Brill JA. Type II phosphatidylinositol 4-kinase regulates trafficking of secretory granule proteins in Drosophila. J Cell Sci 2012. [DOI: 10.1242/jcs.117010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Burgess J, Del Bel LM, Ma CIJ, Barylko B, Polevoy G, Rollins J, Albanesi JP, Krämer H, Brill JA. Type II phosphatidylinositol 4-kinase regulates trafficking of secretory granule proteins in Drosophila. Development 2012; 139:3040-50. [PMID: 22791894 DOI: 10.1242/dev.077644] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Type II phosphatidylinositol 4-kinase (PI4KII) produces the lipid phosphatidylinositol 4-phosphate (PI4P), a key regulator of membrane trafficking. Here, we generated genetic models of the sole Drosophila melanogaster PI4KII gene. A specific requirement for PI4KII emerged in larval salivary glands. In PI4KII mutants, mucin-containing glue granules failed to reach normal size, with glue protein aberrantly accumulating in enlarged Rab7-positive late endosomes. Presence of PI4KII at the Golgi and on dynamic tubular endosomes indicated two distinct foci for its function. First, consistent with the established role of PI4P in the Golgi, PI4KII is required for sorting of glue granule cargo and the granule-associated SNARE Snap24. Second, PI4KII also has an unforeseen function in late endosomes, where it is required for normal retromer dynamics and for formation of tubular endosomes that are likely to be involved in retrieving Snap24 and Lysosomal enzyme receptor protein (Lerp) from late endosomes to the trans-Golgi network. Our genetic analysis of PI4KII in flies thus reveals a novel role for PI4KII in regulating the fidelity of granule protein trafficking in secretory tissues.
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Affiliation(s)
- Jason Burgess
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 1L7, Canada
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11
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Jović M, Kean MJ, Szentpetery Z, Polevoy G, Gingras AC, Brill JA, Balla T. Two phosphatidylinositol 4-kinases control lysosomal delivery of the Gaucher disease enzyme, β-glucocerebrosidase. Mol Biol Cell 2012; 23:1533-45. [PMID: 22337770 PMCID: PMC3327330 DOI: 10.1091/mbc.e11-06-0553] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Trafficking of glucocerebrosidase (GBA) enzyme from the endoplasmic reticulum to the lysosome requires lysosomal integral membrane protein type 2 (LIMP-2), which is a receptor for GBA. This study shows that phosphatidylinositol 4-kinase (PI4K) type IIIβ controls the exit of LIMP-2/GBA complex from the Golgi, while PI4KIIα is required for the post-Golgi trafficking of the complex via the late endosomes. Gaucher disease is a lysosomal storage disorder caused by a defect in the degradation of glucosylceramide catalyzed by the lysosomal enzyme β-glucocerebrosidase (GBA). GBA reaches lysosomes via association with its receptor, lysosomal integral membrane protein type 2 (LIMP-2). We found that distinct phosphatidylinositol 4-kinases (PI4Ks) play important roles at multiple steps in the trafficking pathway of the LIMP-2/GBA complex. Acute depletion of phosphatidylinositol 4-phosphate in the Golgi caused accumulation of LIMP-2 in this compartment, and PI4KIIIβ was found to be responsible for controlling the exit of LIMP-2 from the Golgi. In contrast, depletion of PI4KIIα blocked trafficking at a post-Golgi compartment, leading to accumulation of LIMP-2 in enlarged endosomal vesicles. PI4KIIα depletion also caused secretion of missorted GBA into the medium, which was attenuated by limiting LIMP-2/GBA exit from the Golgi by PI4KIIIβ inhibitors. These studies identified PI4KIIIβ and PI4KIIα as important regulators of lysosomal delivery of GBA, revealing a new element of control to sphingolipid homeostasis by phosphoinositides.
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Affiliation(s)
- Marko Jović
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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12
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Fabian L, Wei HC, Rollins J, Noguchi T, Blankenship JT, Bellamkonda K, Polevoy G, Gervais L, Guichet A, Fuller MT, Brill JA. Phosphatidylinositol 4,5-bisphosphate directs spermatid cell polarity and exocyst localization in Drosophila. Mol Biol Cell 2010; 21:1546-55. [PMID: 20237161 PMCID: PMC2861613 DOI: 10.1091/mbc.e09-07-0582] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 02/18/2010] [Accepted: 03/05/2010] [Indexed: 01/15/2023] Open
Abstract
During spermiogenesis, Drosophila melanogaster spermatids coordinate their elongation in interconnected cysts that become highly polarized, with nuclei localizing to one end and sperm tail growth occurring at the other. Remarkably little is known about the signals that drive spermatid polarity and elongation. Here we identify phosphoinositides as critical regulators of these processes. Reduction of plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) by low-level expression of the PIP(2) phosphatase SigD or mutation of the PIP(2) biosynthetic enzyme Skittles (Sktl) results in dramatic defects in spermatid cysts, which become bipolar and fail to fully elongate. Defects in polarity are evident from the earliest stages of elongation, indicating that phosphoinositides are required for establishment of polarity. Sktl and PIP(2) localize to the growing end of the cysts together with the exocyst complex. Strikingly, the exocyst becomes completely delocalized when PIP(2) levels are reduced, and overexpression of Sktl restores exocyst localization and spermatid cyst polarity. Moreover, the exocyst is required for polarity, as partial loss of function of the exocyst subunit Sec8 results in bipolar cysts. Our data are consistent with a mechanism in which localized synthesis of PIP(2) recruits the exocyst to promote targeted membrane delivery and polarization of the elongating cysts.
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Affiliation(s)
- Lacramioara Fabian
- *Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1L7, Canada
| | - Ho-Chun Wei
- *Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1L7, Canada
| | - Janet Rollins
- Division of Natural Science, The College of Mount Saint Vincent, Riverdale, NY 10471
| | - Tatsuhiko Noguchi
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | | | - Kishan Bellamkonda
- *Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Gordon Polevoy
- *Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1L7, Canada
| | - Louis Gervais
- Institut Jacques Monod, CNRS-University of Paris Diderot, 75205 Paris, France; and
| | - Antoine Guichet
- Institut Jacques Monod, CNRS-University of Paris Diderot, 75205 Paris, France; and
| | - Margaret T. Fuller
- Department of Developmental Biology, Stanford University School of Medicine, Palo Alto, CA 95305
| | - Julie A. Brill
- *Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Polevoy G, Wei HC, Wong R, Szentpetery Z, Kim YJ, Goldbach P, Steinbach SK, Balla T, Brill JA. Dual roles for the Drosophila PI 4-kinase four wheel drive in localizing Rab11 during cytokinesis. ACTA ACUST UNITED AC 2010; 187:847-58. [PMID: 19995935 PMCID: PMC2806325 DOI: 10.1083/jcb.200908107] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Successful completion of cytokinesis relies on addition of new membrane, and requires the recycling endosome regulator Rab11, which localizes to the midzone. Despite the critical role of Rab11 in this process, little is known about the formation and composition of Rab11-containing organelles. Here, we identify the phosphatidylinositol (PI) 4-kinase III beta four wheel drive (Fwd) as a key regulator of Rab11 during cytokinesis in Drosophila melanogaster spermatocytes. We show Fwd is required for synthesis of PI 4-phosphate (PI4P) on Golgi membranes and for formation of PI4P-containing secretory organelles that localize to the midzone. Fwd binds and colocalizes with Rab11 on Golgi membranes, and is required for localization of Rab11 in dividing cells. A kinase-dead version of Fwd also binds Rab11 and partially restores cytokinesis to fwd mutant flies. Moreover, activated Rab11 partially suppresses loss of fwd. Our data suggest Fwd plays catalytic and noncatalytic roles in regulating Rab11 during cytokinesis.
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Affiliation(s)
- Gordon Polevoy
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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14
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Wei HC, Rollins J, Fabian L, Hayes M, Polevoy G, Bazinet C, Brill JA. Depletion of plasma membrane PtdIns(4,5)P2 reveals essential roles for phosphoinositides in flagellar biogenesis. J Cell Sci 2008; 121:1076-84. [PMID: 18334551 DOI: 10.1242/jcs.024927] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Axonemes are microtubule-based organelles of crucial importance in the structure and function of eukaryotic cilia and flagella. Despite great progress in understanding how axonemes are assembled, the signals that initiate axoneme outgrowth remain unknown. Here, we identified phosphatidylinositol phosphates (phosphoinositides) as key regulators of early stages of axoneme outgrowth in Drosophila melanogaster spermatogenesis. In a study of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] function in developing Drosophila male germ cells, we depleted PtdIns(4,5)P2 by expression of a potent phosphoinositide phosphatase. Phosphatase expression dramatically inhibited sperm tail formation and perturbed microtubule organization in a manner reversible by co-expression of a PtdIns 4-phosphate 5-kinase. Depletion of PtdIns(4,5)P2 caused increased levels of basal body gamma-tubulin and altered the distribution of proteins known to be required for axoneme assembly. Examination of PtdIns(4,5)P2-depleted spermatids by transmission electron microscopy revealed defects in basal body docking to the nuclear envelope, and in axoneme architecture and integrity of the developing flagellar axoneme and axial sheath. Our results provide the first evidence that phosphoinositides act at several steps during flagellar biogenesis, coordinately regulating microtubule and membrane organization. They further suggest that phosphoinositides play evolutionarily conserved roles in flagella and cilia, across phyla and in structurally diverse cell types.
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Affiliation(s)
- Ho-Chun Wei
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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Wong R, Hadjiyanni I, Wei HC, Polevoy G, McBride R, Sem KP, Brill JA. PIP2 Hydrolysis and Calcium Release Are Required for Cytokinesis in Drosophila Spermatocytes. Curr Biol 2005; 15:1401-6. [PMID: 16085493 DOI: 10.1016/j.cub.2005.06.060] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 06/15/2005] [Accepted: 06/16/2005] [Indexed: 11/16/2022]
Abstract
The role of calcium (Ca(2+)) in cytokinesis is controversial, and the precise pathways that lead to its release during cleavage are not well understood. Ca(2+) is released from intracellular stores by binding of inositol trisphosphate (IP3) to the IP3 receptor (IP3R), yet no clear role in cytokinesis has been established for the precursor of IP3, phosphatidylinositol 4,5-bisphosphate (PIP2). Here, using transgenic flies expressing PLCdelta-PH-GFP, which specifically binds PIP2, we identify PIP2 in the plasma membrane and cleavage furrows of dividing Drosophila melanogaster spermatocytes, and we establish that this phospholipid is required for continued ingression but not for initiation of cytokinesis. In addition, by inhibiting phospholipase C, we show that PIP2 must be hydrolyzed to maintain cleavage furrow stability. Using an IP3R antagonist and a Ca(2+) chelator to examine the roles of IP3R and Ca(2+) in cytokinesis, we demonstrate that both of these factors are required for cleavage furrow stability, although Ca(2+) is dispensable for cleavage plane specification and initiation of furrowing. Strikingly, providing cells with Ca(2+) obviates the need to hydrolyze PIP2. Thus, PIP2, PIP2 hydrolysis, and Ca(2+) are required for the normal progression of cytokinesis in these cells.
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Affiliation(s)
- Raymond Wong
- Program in Developmental Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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Simcha I, Kirkpatrick C, Sadot E, Shtutman M, Polevoy G, Geiger B, Peifer M, Ben-Ze'ev A. Cadherin sequences that inhibit beta-catenin signaling: a study in yeast and mammalian cells. Mol Biol Cell 2001; 12:1177-88. [PMID: 11294915 PMCID: PMC32295 DOI: 10.1091/mbc.12.4.1177] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Drosophila Armadillo and its mammalian homologue beta-catenin are scaffolding proteins involved in the assembly of multiprotein complexes with diverse biological roles. They mediate adherens junction assembly, thus determining tissue architecture, and also transduce Wnt/Wingless intercellular signals, which regulate embryonic cell fates and, if inappropriately activated, contribute to tumorigenesis. To learn more about Armadillo/beta-catenin's scaffolding function, we examined in detail its interaction with one of its protein targets, cadherin. We utilized two assay systems: the yeast two-hybrid system to study cadherin binding in the absence of Armadillo/beta-catenin's other protein partners, and mammalian cells where interactions were assessed in their presence. We found that segments of the cadherin cytoplasmic tail as small as 23 amino acids bind Armadillo or beta-catenin in yeast, whereas a slightly longer region is required for binding in mammalian cells. We used mutagenesis to identify critical amino acids required for cadherin interaction with Armadillo/beta-catenin. Expression of such short cadherin sequences in mammalian cells did not affect adherens junctions but effectively inhibited beta-catenin-mediated signaling. This suggests that the interaction between beta-catenin and T cell factor family transcription factors is a sensitive target for disruption, making the use of analogues of these cadherin derivatives a potentially useful means to suppress tumor progression.
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Affiliation(s)
- I Simcha
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel, 76100
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