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Leibfried A, Müller S, Ephrussi A. A Cdc42-regulated actin cytoskeleton mediates Drosophila oocyte polarization. Development 2013; 140:362-71. [DOI: 10.1242/dev.089250] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Polarity of the Drosophila oocyte is essential for correct development of the egg and future embryo. The Par proteins Par-6, aPKC and Bazooka are needed to maintain oocyte polarity and localize to specific domains early in oocyte development. To date, no upstream regulator or mechanism for localization of the Par proteins in the oocyte has been identified. We have analyzed the role of the small GTPase Cdc42 in oocyte polarity. We show that Cdc42 is required to maintain oocyte fate, which it achieves by mediating localization of Par proteins at distinct sites within this cell. We establish that Cdc42 localization itself is polarized to the anterolateral cortex of the oocyte and that Cdc42 is needed for maintenance of oocyte polarity throughout oogenesis. Our data show that Cdc42 ensures the integrity of the oocyte actin network and that disruption of this network with Latrunculin A phenocopies loss of Cdc42 or Par protein function in early stages of oogenesis. Finally, we show that Cdc42 and Par proteins, as well as Cdc42/Par and Arp3, interact in the context of oocyte polarity, and that loss of Par proteins reciprocally affects Cdc42 localization and the actin network. These results reveal a mutual dependence between Par proteins and Cdc42 for their localization, regulation of the actin cytoskeleton and, consequently, for the establishment of oocyte polarity. This most likely allows for the robustness in symmetry breaking in the cell.
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Affiliation(s)
- Andrea Leibfried
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Sandra Müller
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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Lennerz JK, Hurov JB, White LS, Lewandowski KT, Prior JL, Planer GJ, Gereau RW, Piwnica-Worms D, Schmidt RE, Piwnica-Worms H. Loss of Par-1a/MARK3/C-TAK1 kinase leads to reduced adiposity, resistance to hepatic steatosis, and defective gluconeogenesis. Mol Cell Biol 2010; 30:5043-56. [PMID: 20733003 PMCID: PMC2953066 DOI: 10.1128/mcb.01472-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 12/22/2009] [Accepted: 07/29/2010] [Indexed: 12/11/2022] Open
Abstract
Par-1 is an evolutionarily conserved protein kinase required for polarity in worms, flies, frogs, and mammals. The mammalian Par-1 family consists of four members. Knockout studies of mice implicate Par-1b/MARK2/EMK in regulating fertility, immune homeostasis, learning, and memory as well as adiposity, insulin hypersensitivity, and glucose metabolism. Here, we report phenotypes of mice null for a second family member (Par-1a/MARK3/C-TAK1) that exhibit increased energy expenditure, reduced adiposity with unaltered glucose handling, and normal insulin sensitivity. Knockout mice were protected against high-fat diet-induced obesity and displayed attenuated weight gain, complete resistance to hepatic steatosis, and improved glucose handling with decreased insulin secretion. Overnight starvation led to complete hepatic glycogen depletion, associated hypoketotic hypoglycemia, increased hepatocellular autophagy, and increased glycogen synthase levels in Par-1a(-/-) but not in control or Par-1b(-/-) mice. The intercrossing of Par-1a(-/-) with Par-1b(-/-) mice revealed that at least one of the four alleles is necessary for embryonic survival. The severity of phenotypes followed a rank order, whereby the loss of one Par-1b allele in Par-1a(-/-) mice conveyed milder phenotypes than the loss of one Par-1a allele in Par-1b(-/-) mice. Thus, although Par-1a and Par-1b can compensate for one another during embryogenesis, their individual disruption gives rise to distinct metabolic phenotypes in adult mice.
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Affiliation(s)
- Jochen K. Lennerz
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Jonathan B. Hurov
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Lynn S. White
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Katherine T. Lewandowski
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Julie L. Prior
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - G. James Planer
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Robert W. Gereau
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - David Piwnica-Worms
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Robert E. Schmidt
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Helen Piwnica-Worms
- Department of Pathology and Immunology, Department of Cell Biology and Physiology, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Neurology, Neuromuscular Laboratory, Washington University Pain Center and Department of Anesthesiology, Department of Developmental Biology, Department of Internal Medicine, BRIGHT Institute, Washington University School of Medicine, St. Louis, Missouri 63110, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
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