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Stansak KL, Baum LD, Ghosh S, Thapa P, Vanga V, Walters BJ. PCP auto count: a novel Fiji/ImageJ plug-in for automated quantification of planar cell polarity and cell counting. Front Cell Dev Biol 2024; 12:1394031. [PMID: 38827526 PMCID: PMC11140036 DOI: 10.3389/fcell.2024.1394031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/19/2024] [Indexed: 06/04/2024] Open
Abstract
Introdution: During development, planes of cells give rise to complex tissues and organs. The proper functioning of these tissues is critically dependent on proper inter- and intra-cellular spatial orientation, a feature known as planar cell polarity (PCP). To study the genetic and environmental factors affecting planar cell polarity, investigators must often manually measure cell orientations, which is a time-consuming endeavor. To automate cell counting and planar cell polarity data collection we developed a Fiji/ImageJ plug-in called PCP Auto Count (PCPA). Methods: PCPA analyzes binary images and identifies "chunks" of white pixels that contain "caves" of infiltrated black pixels. For validation, inner ear sensory epithelia including cochleae and utricles from mice were immunostained for βII-spectrin and imaged with a confocal microscope. Images were preprocessed using existing Fiji functionality to enhance contrast, make binary, and reduce noise. An investigator rated PCPA cochlear hair cell angle measurements for accuracy using a one to five agreement scale. For utricle samples, PCPA derived measurements were directly compared against manually derived angle measurements and the concordance correlation coefficient (CCC) and Bland-Altman limits of agreement were calculated. PCPA was also tested against previously published images examining PCP in various tissues and across various species suggesting fairly broad utility. Results: PCPA was able to recognize and count 99.81% of cochlear hair cells, and was able to obtain ideally accurate planar cell polarity measurements for at least 96% of hair cells. When allowing for a <10° deviation from "perfect" measurements, PCPA's accuracy increased to 98%-100% for all users and across all samples. When PCPA's measurements were compared with manual angle measurements for E17.5 utricles there was negligible bias (<0.5°), and a CCC of 0.999. Qualitative examination of example images of Drosophila ommatidia, mouse ependymal cells, and mouse radial progenitors revealed a high level of accuracy for PCPA across a variety of stains, tissue types, and species. Discussion: Altogether, the data suggest that the PCPA plug-in suite is a robust and accurate tool for the automated collection of cell counts and PCP angle measurements.
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Affiliation(s)
| | | | | | | | | | - Bradley J. Walters
- University of Mississippi Medical Center, Department of Otolaryngology—Head and Neck Surgery, Jackson, MS, United States
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2
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Jarysta A, Tadenev ALD, Day M, Krawchuk B, Low BE, Wiles MV, Tarchini B. Inhibitory G proteins play multiple roles to polarize sensory hair cell morphogenesis. eLife 2024; 12:RP88186. [PMID: 38651641 PMCID: PMC11037916 DOI: 10.7554/elife.88186] [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] [Indexed: 04/25/2024] Open
Abstract
Inhibitory G alpha (GNAI or Gαi) proteins are critical for the polarized morphogenesis of sensory hair cells and for hearing. The extent and nature of their actual contributions remains unclear, however, as previous studies did not investigate all GNAI proteins and included non-physiological approaches. Pertussis toxin can downregulate functionally redundant GNAI1, GNAI2, GNAI3, and GNAO proteins, but may also induce unrelated defects. Here, we directly and systematically determine the role(s) of each individual GNAI protein in mouse auditory hair cells. GNAI2 and GNAI3 are similarly polarized at the hair cell apex with their binding partner G protein signaling modulator 2 (GPSM2), whereas GNAI1 and GNAO are not detected. In Gnai3 mutants, GNAI2 progressively fails to fully occupy the sub-cellular compartments where GNAI3 is missing. In contrast, GNAI3 can fully compensate for the loss of GNAI2 and is essential for hair bundle morphogenesis and auditory function. Simultaneous inactivation of Gnai2 and Gnai3 recapitulates for the first time two distinct types of defects only observed so far with pertussis toxin: (1) a delay or failure of the basal body to migrate off-center in prospective hair cells, and (2) a reversal in the orientation of some hair cell types. We conclude that GNAI proteins are critical for hair cells to break planar symmetry and to orient properly before GNAI2/3 regulate hair bundle morphogenesis with GPSM2.
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Affiliation(s)
| | | | - Matthew Day
- The Jackson LaboratoryBar HarborUnited States
| | | | | | | | - Basile Tarchini
- The Jackson LaboratoryBar HarborUnited States
- Tufts University School of MedicineBostonUnited States
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3
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Nürnberg B, Beer-Hammer S, Reisinger E, Leiss V. Non-canonical G protein signaling. Pharmacol Ther 2024; 255:108589. [PMID: 38295906 DOI: 10.1016/j.pharmthera.2024.108589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/18/2023] [Accepted: 01/08/2024] [Indexed: 02/17/2024]
Abstract
The original paradigm of classical - also referred to as canonical - cellular signal transduction of heterotrimeric G proteins (G protein) is defined by a hierarchical, orthograde interaction of three players: the agonist-activated G protein-coupled receptor (GPCR), which activates the transducing G protein, that in turn regulates its intracellular effectors. This receptor-transducer-effector concept was extended by the identification of regulators and adapters such as the regulators of G protein signaling (RGS), receptor kinases like βARK, or GPCR-interacting arrestin adapters that are integrated into this canonical signaling process at different levels to enable fine-tuning. Finally, the identification of atypical signaling mechanisms of classical regulators, together with the discovery of novel modulators, added a new and fascinating dimension to the cellular G protein signal transduction. This heterogeneous group of accessory G protein modulators was coined "activators of G protein signaling" (AGS) proteins and plays distinct roles in canonical and non-canonical G protein signaling pathways. AGS proteins contribute to the control of essential cellular functions such as cell development and division, intracellular transport processes, secretion, autophagy or cell movements. As such, they are involved in numerous biological processes that are crucial for diseases, like diabetes mellitus, cancer, and stroke, which represent major health burdens. Although the identification of a large number of non-canonical G protein signaling pathways has broadened the spectrum of this cellular communication system, their underlying mechanisms, functions, and biological effects are poorly understood. In this review, we highlight and discuss atypical G protein-dependent signaling mechanisms with a focus on inhibitory G proteins (Gi) involved in canonical and non-canonical signal transduction, review recent developments and open questions, address the potential of new approaches for targeted pharmacological interventions.
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Affiliation(s)
- Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany.
| | - Sandra Beer-Hammer
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany
| | - Ellen Reisinger
- Gene Therapy for Hearing Impairment Group, Department of Otolaryngology - Head & Neck Surgery, University of Tübingen Medical Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany
| | - Veronika Leiss
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany
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4
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Stansak KL, Baum LD, Ghosh S, Thapa P, Vanga V, Walters BJ. PCP Auto Count: A Novel Fiji/ImageJ plug-in for automated quantification of planar cell polarity and cell counting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.578047. [PMID: 38352473 PMCID: PMC10862842 DOI: 10.1101/2024.01.30.578047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Background During development, planes of cells give rise to complex tissues and organs. The proper functioning of these tissues is critically dependent on proper inter- and intra-cellular spatial orientation, a feature known as planar cell polarity (PCP). To study the genetic and environmental factors affecting planar cell polarity investigators must often manually measure cell orientations, which is a time-consuming endeavor. Methodology To automate cell counting and planar cell polarity data collection we developed a Fiji/ImageJ plug-in called PCP Auto Count (PCPA). PCPA analyzes binary images and identifies "chunks" of white pixels that contain "caves" of infiltrated black pixels. Inner ear sensory epithelia including cochleae (P4) and utricles (E17.5) from mice were immunostained for βII-spectrin and imaged on a confocal microscope. Images were preprocessed using existing Fiji functionality to enhance contrast, make binary, and reduce noise. An investigator rated PCPA cochlear angle measurements for accuracy using a 1-5 agreement scale. For utricle samples, we directly compared PCPA derived measurements against manually derived angle measurements using concordance correlation coefficients (CCC) and Bland-Altman limits of agreement. Finally, PCPA was tested against a variety of images copied from publications examining PCP in various tissues and across various species. Results PCPA was able to recognize and count 99.81% of cochlear hair cells (n = 1,1541 hair cells) in a sample set, and was able to obtain ideally accurate planar cell polarity measurements for over 96% of hair cells. When allowing for a <10° deviation from "perfect" measurements, PCPA's accuracy increased to >98%. When manual angle measurements for E17.5 utricles were compared, PCPA's measurements fell within -9 to +10 degrees of manually obtained mean angle measures with a CCC of 0.999. Qualitative examination of example images of Drosophila ommatidia, mouse ependymal cells, and mouse radial progenitors revealed a high level of accuracy for PCPA across a variety of stains, tissue types, and species. Altogether, the data suggest that the PCPA plug-in suite is a robust and accurate tool for the automated collection of cell counts and PCP angle measurements.
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Affiliation(s)
- Kendra L. Stansak
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Luke D. Baum
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Sumana Ghosh
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Punam Thapa
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Vineel Vanga
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Bradley J. Walters
- Department of Otolaryngology - Head and Neck Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
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Jarysta A, Tadenev ALD, Day M, Krawchuk B, Low BE, Wiles MV, Tarchini B. Inhibitory G proteins play multiple roles to polarize sensory hair cell morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.25.542257. [PMID: 37292807 PMCID: PMC10245865 DOI: 10.1101/2023.05.25.542257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Inhibitory G alpha (GNAI or Gαi) proteins are critical for the polarized morphogenesis of sensory hair cells and for hearing. The extent and nature of their actual contributions remains unclear, however, as previous studies did not investigate all GNAI proteins and included non-physiological approaches. Pertussis toxin can downregulate functionally redundant GNAI1, GNAI2, GNAI3 and GNAO proteins, but may also induce unrelated defects. Here we directly and systematically determine the role(s) of each individual GNAI protein in mouse auditory hair cells. GNAI2 and GNAI3 are similarly polarized at the hair cell apex with their binding partner GPSM2, whereas GNAI1 and GNAO are not detected. In Gnai3 mutants, GNAI2 progressively fails to fully occupy the subcellular compartments where GNAI3 is missing. In contrast, GNAI3 can fully compensate for the loss of GNAI2 and is essential for hair bundle morphogenesis and auditory function. Simultaneous inactivation of Gnai2 and Gnai3 recapitulates for the first time two distinct types of defects only observed so far with pertussis toxin: 1) a delay or failure of the basal body to migrate off-center in prospective hair cells, and 2) a reversal in the orientation of some hair cell types. We conclude that GNAI proteins are critical for hair cells to break planar symmetry and to orient properly before GNAI2/3 regulate hair bundle morphogenesis with GPSM2.
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6
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Shi DL. Planar cell polarity regulators in asymmetric organogenesis during development and disease. J Genet Genomics 2023; 50:63-76. [PMID: 35809777 DOI: 10.1016/j.jgg.2022.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 12/22/2022]
Abstract
The phenomenon of planar cell polarity is critically required for a myriad of morphogenetic processes in metazoan and is accurately controlled by several conserved modules. Six "core" proteins, including Frizzled, Flamingo (Celsr), Van Gogh (Vangl), Dishevelled, Prickle, and Diego (Ankrd6), are major components of the Wnt/planar cell polarity pathway. The Fat/Dchs protocadherins and the Scrib polarity complex also function to instruct cellular polarization. In vertebrates, all these pathways are essential for tissue and organ morphogenesis, such as neural tube closure, left-right symmetry breaking, heart and gut morphogenesis, lung and kidney branching, stereociliary bundle orientation, and proximal-distal limb elongation. Mutations in planar polarity genes are closely linked to various congenital diseases. Striking advances have been made in deciphering their contribution to the establishment of spatially oriented pattern in developing organs and the maintenance of tissue homeostasis. The challenge remains to clarify the complex interplay of different polarity pathways in organogenesis and the link of cell polarity to cell fate specification. Interdisciplinary approaches are also important to understand the roles of mechanical forces in coupling cellular polarization and differentiation. This review outlines current advances on planar polarity regulators in asymmetric organ formation, with the aim to identify questions that deserve further investigation.
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Affiliation(s)
- De-Li Shi
- Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China; Laboratory of Developmental Biology, CNRS-UMR7622, Institut de Biologie Paris-Seine (IBPS), Sorbonne University, 75005 Paris, France.
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7
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Akturk A, Day M, Tarchini B. RGS12 polarizes the GPSM2-GNAI complex to organize and elongate stereocilia in sensory hair cells. SCIENCE ADVANCES 2022; 8:eabq2826. [PMID: 36260679 PMCID: PMC9581478 DOI: 10.1126/sciadv.abq2826] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/31/2022] [Indexed: 06/10/2023]
Abstract
Inhibitory G proteins (GNAI/Gαi) bind to the scaffold G protein signaling modulator 2 (GPSM2) to form a conserved polarity complex that regulates cytoskeleton organization. GPSM2 keeps GNAI in a guanosine diphosphate (GDP)-bound state, but how GPSM2-GNAI is generated or relates to heterotrimeric G protein signaling remains unclear. We find that RGS12, a GTPase-activating protein (GAP), is required to polarize GPSM2-GNAI at the hair cell apical membrane and to organize mechanosensory stereocilia in rows of graded heights. Accordingly, RGS12 and the guanine nucleotide exchange factor (GEF) DAPLE are asymmetrically co-enriched at the hair cell apical junction, and Rgs12 mouse mutants are deaf. GPSM2 and RGS12 share GoLoco motifs that stabilize GNAI(GDP), and GPSM2 outcompetes RGS12 to bind GNAI. Our results suggest that polarized GEF/GAP junctional activity might dissociate heterotrimeric G proteins, generating free GNAI(GDP) for GPSM2 at the adjacent apical membrane. GPSM2-GNAI(GDP), in turn, imparts asymmetry to the forming stereocilia to enable sensory function in hair cells.
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Affiliation(s)
- Anil Akturk
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Matthew Day
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- School of Medicine, Tufts University, Boston, MA 02111, USA
- Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, ME 04469, USA
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8
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Bieniussa L, Jain I, Bosch Grau M, Juergens L, Hagen R, Janke C, Rak K. Microtubule and auditory function - an underestimated connection. Semin Cell Dev Biol 2022; 137:74-86. [PMID: 35144861 DOI: 10.1016/j.semcdb.2022.02.004] [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: 07/01/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 10/19/2022]
Abstract
The organ of Corti, located in the cochlea within the inner ear is the receptor organ for hearing. It converts auditory signals into neuronal action potentials that are transmitted to the brain for further processing. The mature organ of Corti consists of a variety of highly differentiated sensory cells that fulfil unique tasks in the processing of auditory signals. The actin and microtubule cytoskeleton play essential function in hearing, however so far, more attention has been paid to the role of actin. Microtubules play important roles in maintaining cellular structure and intracellular transport in virtually all eukaryotic cells. Their functions are controlled by interactions with a large variety of microtubule-associated proteins (MAPs) and molecular motors. Current advances show that tubulin posttranslational modifications, as well as tubulin isotypes could play key roles in modulating microtubule properties and functions in cells. These mechanisms could have various effects on the stability and functions of microtubules in the highly specialised cells of the cochlea. Here, we review the current understanding of the role of microtubule-regulating mechanisms in the function of the cochlea and their implications for hearing, which highlights the importance of microtubules in the field of hearing research.
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Affiliation(s)
- Linda Bieniussa
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Würzburg, Germany
| | - Ipsa Jain
- Institute of Stem cell Biology and Regenerative Medicine, Bangalore, India
| | - Montserrat Bosch Grau
- Genetics and Physiology of Hearing Laboratory, Institute Pasteur, 75015 Paris, France
| | - Lukas Juergens
- Department of Ophthalmology, University of Duesseldorf, Germany
| | - Rudolf Hagen
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Würzburg, Germany
| | - Carsten Janke
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France; Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Kristen Rak
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Würzburg, Germany.
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Daple deficiency causes hearing loss in adult mice by inducing defects in cochlear stereocilia and apical microtubules. Sci Rep 2021; 11:20224. [PMID: 34642354 PMCID: PMC8511111 DOI: 10.1038/s41598-021-96232-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 07/20/2021] [Indexed: 12/29/2022] Open
Abstract
The V-shaped arrangement of hair bundles on cochlear hair cells is critical for auditory sensing. However, regulation of hair bundle arrangements has not been fully understood. Recently, defects in hair bundle arrangement were reported in postnatal Dishevelled-associating protein (ccdc88c, alias Daple)-deficient mice. In the present study, we found that adult Daple−/− mice exhibited hearing disturbances over a broad frequency range through auditory brainstem response testing. Consistently, distorted patterns of hair bundles were detected in almost all regions, more typically in the basal region of the cochlear duct. In adult Daple−/− mice, apical microtubules were irregularly aggregated, and the number of microtubules attached to plasma membranes was decreased. Similar phenotypes were manifested upon nocodazole treatment in a wild type cochlea culture without affecting the microtubule structure of the kinocilium. These results indicate critical role of Daple in hair bundle arrangement through the orchestration of apical microtubule distribution, and thereby in hearing, especially at high frequencies.
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10
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Jarysta A, Tarchini B. Multiple PDZ domain protein maintains patterning of the apical cytoskeleton in sensory hair cells. Development 2021; 148:270996. [PMID: 34228789 DOI: 10.1242/dev.199549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/25/2021] [Indexed: 12/29/2022]
Abstract
Sound transduction occurs in the hair bundle, the apical compartment of sensory hair cells in the inner ear. The hair bundle is formed of actin-based stereocilia aligned in rows of graded heights. It was previously shown that the GNAI-GPSM2 complex is part of a developmental blueprint that defines the polarized organization of the apical cytoskeleton in hair cells, including stereocilia distribution and elongation. Here, we report a role for multiple PDZ domain (MPDZ) protein during apical hair cell morphogenesis in mouse. We show that MPDZ is enriched at the hair cell apical membrane along with MAGUK p55 subfamily member 5 (MPP5/PALS1) and the Crumbs protein CRB3. MPDZ is required there to maintain the proper segregation of apical blueprint proteins, including GNAI-GPSM2. Loss of the blueprint coincides with misaligned stereocilia placement in Mpdz mutant hair cells, and results in permanently misshapen hair bundles. Graded molecular and structural defects along the cochlea can explain the profile of hearing loss in Mpdz mutants, where deficits are most severe at high frequencies.
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Affiliation(s)
| | - Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME 04609, USA.,Department of Medicine, Tufts University, Boston, MA 02111, USA.,Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, ME 04469, USA
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11
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Donati A, Anselme I, Schneider-Maunoury S, Vesque C. Planar polarization of cilia in the zebrafish floor-plate involves Par3-mediated posterior localization of highly motile basal bodies. Development 2021; 148:269080. [PMID: 34104942 DOI: 10.1242/dev.196386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 06/01/2021] [Indexed: 12/12/2022]
Abstract
Epithelial cilia, whether motile or primary, often display an off-center planar localization within the apical cell surface. This form of planar cell polarity (PCP) involves the asymmetric positioning of the ciliary basal body (BB). Using the monociliated epithelium of the embryonic zebrafish floor-plate, we investigated the dynamics and mechanisms of BB polarization by live imaging. BBs were highly motile, making back-and-forth movements along the antero-posterior (AP) axis and contacting both the anterior and posterior membranes. Contacts exclusively occurred at junctional Par3 patches and were often preceded by membrane digitations extending towards the BB, suggesting focused cortical pulling forces. Accordingly, BBs and Par3 patches were linked by dynamic microtubules. Later, BBs became less motile and eventually settled at posterior apical junctions enriched in Par3. BB posterior positioning followed Par3 posterior enrichment and was impaired upon Par3 depletion or disorganization of Par3 patches. In the PCP mutant vangl2, BBs were still motile but displayed poorly oriented membrane contacts that correlated with Par3 patch fragmentation and lateral spreading. Thus, we propose an unexpected function for posterior Par3 enrichment in controlling BB positioning downstream of the PCP pathway.
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Affiliation(s)
- Antoine Donati
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS), Developmental Biology Unit, 75005 Paris, France
| | - Isabelle Anselme
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS), Developmental Biology Unit, 75005 Paris, France
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS), Developmental Biology Unit, 75005 Paris, France
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS), Developmental Biology Unit, 75005 Paris, France
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12
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Kindt KS, Akturk A, Jarysta A, Day M, Beirl A, Flonard M, Tarchini B. EMX2-GPR156-Gαi reverses hair cell orientation in mechanosensory epithelia. Nat Commun 2021; 12:2861. [PMID: 34001891 PMCID: PMC8129141 DOI: 10.1038/s41467-021-22997-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 04/10/2021] [Indexed: 12/21/2022] Open
Abstract
Hair cells detect sound, head position or water movements when their mechanosensory hair bundle is deflected. Each hair bundle has an asymmetric architecture that restricts stimulus detection to a single axis. Coordinated hair cell orientations within sensory epithelia further tune stimulus detection at the organ level. Here, we identify GPR156, an orphan GPCR of unknown function, as a critical regulator of hair cell orientation. We demonstrate that the transcription factor EMX2 polarizes GPR156 distribution, enabling it to signal through Gαi and trigger a 180° reversal in hair cell orientation. GPR156-Gαi mediated reversal is essential to establish hair cells with mirror-image orientations in mouse otolith organs in the vestibular system and in zebrafish lateral line. Remarkably, GPR156-Gαi also instructs hair cell reversal in the auditory epithelium, despite a lack of mirror-image organization. Overall, our work demonstrates that conserved GPR156-Gαi signaling is integral to the framework that builds directional responses into mechanosensory epithelia.
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MESH Headings
- Animals
- Cell Polarity/genetics
- Epithelium/metabolism
- Female
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hair Cells, Auditory/cytology
- Hair Cells, Auditory/metabolism
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Microscopy, Confocal/methods
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Zebrafish/metabolism
- Mice
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Affiliation(s)
- Katie S Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | - Alisha Beirl
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | | | - Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME, USA.
- Department of Medicine, Tufts University, Boston, MA, USA.
- Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, ME, USA.
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13
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Nakayama S, Yano T, Namba T, Konishi S, Takagishi M, Herawati E, Nishida T, Imoto Y, Ishihara S, Takahashi M, Furuta K, Oiwa K, Tamura A, Tsukita S. Planar cell polarity induces local microtubule bundling for coordinated ciliary beating. J Cell Biol 2021; 220:212042. [PMID: 33929515 PMCID: PMC8094116 DOI: 10.1083/jcb.202010034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
Multiciliated cells (MCCs) in tracheas generate mucociliary clearance through coordinated ciliary beating. Apical microtubules (MTs) play a crucial role in this process by organizing the planar cell polarity (PCP)-dependent orientation of ciliary basal bodies (BBs), for which the underlying molecular basis remains elusive. Herein, we found that the deficiency of Daple, a dishevelled-associating protein, in tracheal MCCs impaired the planar polarized apical MTs without affecting the core PCP proteins, causing significant defects in the BB orientation at the cell level but not the tissue level. Using live-cell imaging and ultra-high voltage electron microscope tomography, we found that the apical MTs accumulated and were stabilized by side-by-side association with one side of the apical junctional complex, to which Daple was localized. In vitro binding and single-molecule imaging revealed that Daple directly bound to, bundled, and stabilized MTs through its dimerization. These features convey a PCP-related molecular basis for the polarization of apical MTs, which coordinate ciliary beating in tracheal MCCs.
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Affiliation(s)
- Shogo Nakayama
- Laboratory of Barriology and Cell Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tomoki Yano
- Laboratory of Barriology and Cell Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Toshinori Namba
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Satoshi Konishi
- Laboratory of Barriology and Cell Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Maki Takagishi
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX
| | - Elisa Herawati
- Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Surakarta, Indonesia
| | - Tomoki Nishida
- Japan Textile Products Quality and Technology Center, Hyogo, Japan
| | - Yasuo Imoto
- Japan Textile Products Quality and Technology Center, Hyogo, Japan
| | - Shuji Ishihara
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Masahide Takahashi
- Department of Pathology, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Japan
| | - Ken'ya Furuta
- Advanced Information and Communications Technology Research Institute, National Institute of Information and Communications Technology, Hyogo, Japan
| | - Kazuhiro Oiwa
- Advanced Information and Communications Technology Research Institute, National Institute of Information and Communications Technology, Hyogo, Japan
| | - Atsushi Tamura
- Laboratory of Barriology and Cell Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Department of Pharmacology, School of Medicine, Teikyo University, Tokyo, Japan.,Advanced Comprehensive Research Organization, Teikyo University, Tokyo, Japan
| | - Sachiko Tsukita
- Laboratory of Barriology and Cell Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Advanced Comprehensive Research Organization, Teikyo University, Tokyo, Japan
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14
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Landin Malt A, Clancy S, Hwang D, Liu A, Smith C, Smith M, Hatley M, Clemens C, Lu X. Non-Canonical Wnt Signaling Regulates Cochlear Outgrowth and Planar Cell Polarity via Gsk3β Inhibition. Front Cell Dev Biol 2021; 9:649830. [PMID: 33937247 PMCID: PMC8086559 DOI: 10.3389/fcell.2021.649830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/17/2021] [Indexed: 11/26/2022] Open
Abstract
During development, sensory hair cells (HCs) in the cochlea assemble a stereociliary hair bundle on their apical surface with planar polarized structure and orientation. We have recently identified a non-canonical, Wnt/G-protein/PI3K signaling pathway that promotes cochlear outgrowth and coordinates planar polarization of the HC apical cytoskeleton and alignment of HC orientation across the cochlear epithelium. Here, we determined the involvement of the kinase Gsk3β and the small GTPase Rac1 in non-canonical Wnt signaling and its regulation of the planar cell polarity (PCP) pathway in the cochlea. We provided the first in vivo evidence for Wnt regulation of Gsk3β activity via inhibitory Ser9 phosphorylation. Furthermore, we carried out genetic rescue experiments of cochlear defects caused by blocking Wnt secretion. We showed that cochlear outgrowth was partially rescued by genetic ablation of Gsk3β but not by expression of stabilized β-catenin; while PCP defects, including hair bundle polarity and junctional localization of the core PCP proteins Fzd6 and Dvl2, were partially rescued by either Gsk3β ablation or constitutive activation of Rac1. Our results identify Gsk3β and likely Rac1 as downstream components of non-canonical Wnt signaling and mediators of cochlear outgrowth, HC planar polarity, and localization of a subset of core PCP proteins in the cochlea.
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Affiliation(s)
- Andre Landin Malt
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Shaylyn Clancy
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Diane Hwang
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Alice Liu
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Connor Smith
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Margaret Smith
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Maya Hatley
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Christopher Clemens
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
| | - Xiaowei Lu
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, United States
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15
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Golden E, Rashwan R, Woodward EA, Sgro A, Wang E, Sorolla A, Waryah C, Tie WJ, Cuyàs E, Ratajska M, Kardaś I, Kozlowski P, Johnstone EKM, See HB, Duffy C, Parry J, Lagerborg KA, Czapiewski P, Menendez JA, Gorczyński A, Wasag B, Pfleger KDG, Curtis C, Lee BK, Kim J, Cursons J, Pavlos NJ, Biernat W, Jain M, Woo AJ, Redfern A, Blancafort P. The oncogene AAMDC links PI3K-AKT-mTOR signaling with metabolic reprograming in estrogen receptor-positive breast cancer. Nat Commun 2021; 12:1920. [PMID: 33772001 PMCID: PMC7998036 DOI: 10.1038/s41467-021-22101-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/25/2021] [Indexed: 12/13/2022] Open
Abstract
Adipogenesis associated Mth938 domain containing (AAMDC) represents an uncharacterized oncogene amplified in aggressive estrogen receptor-positive breast cancers. We uncover that AAMDC regulates the expression of several metabolic enzymes involved in the one-carbon folate and methionine cycles, and lipid metabolism. We show that AAMDC controls PI3K-AKT-mTOR signaling, regulating the translation of ATF4 and MYC and modulating the transcriptional activity of AAMDC-dependent promoters. High AAMDC expression is associated with sensitization to dactolisib and everolimus, and these PI3K-mTOR inhibitors exhibit synergistic interactions with anti-estrogens in IntClust2 models. Ectopic AAMDC expression is sufficient to activate AKT signaling, resulting in estrogen-independent tumor growth. Thus, AAMDC-overexpressing tumors may be sensitive to PI3K-mTORC1 blockers in combination with anti-estrogens. Lastly, we provide evidence that AAMDC can interact with the RabGTPase-activating protein RabGAP1L, and that AAMDC, RabGAP1L, and Rab7a colocalize in endolysosomes. The discovery of the RabGAP1L-AAMDC assembly platform provides insights for the design of selective blockers to target malignancies having the AAMDC amplification.
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Affiliation(s)
- Emily Golden
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Rabab Rashwan
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Department of Microbiology and Immunology, Faculty of Medicine, Minia University, Minia, Egypt
| | - Eleanor A Woodward
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Agustin Sgro
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia
| | - Edina Wang
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Anabel Sorolla
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Charlene Waryah
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Wan Jun Tie
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Elisabet Cuyàs
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Girona Biomedical Research Institute, Girona, Catalonia, Spain
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology, Girona, Catalonia, Spain
| | - Magdalena Ratajska
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland
- The Centre for Cell Therapy and Regenerative Medicine, School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- Department of Pathology, Otago University, Dunedin, New Zealand
| | - Iwona Kardaś
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland
- Laboratory of Clinical Genetics, University Clinical Centre, Gdansk, Poland
| | - Piotr Kozlowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Elizabeth K M Johnstone
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne and Perth, Australia
| | - Heng B See
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne and Perth, Australia
| | - Ciara Duffy
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia
| | - Jeremy Parry
- Department of Anatomical Pathology, Path West Laboratory, Fiona Stanley Hospital Network, Murdoch, WA, Australia
| | - Kim A Lagerborg
- Departments of Medicine and Pharmacology, University of California, San Diego, CA, USA
| | - Piotr Czapiewski
- Department of Pathomorphology, Medical University of Gdansk, Gdansk, Poland
- Institute of Pathology, Dessau Medical Centre, Dessau, Germany
| | - Javier A Menendez
- Girona Biomedical Research Institute, Girona, Catalonia, Spain
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology, Girona, Catalonia, Spain
| | - Adam Gorczyński
- Department of Pathomorphology, Medical University of Gdansk, Gdansk, Poland
| | - Bartosz Wasag
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland
- Laboratory of Clinical Genetics, University Clinical Centre, Gdansk, Poland
| | - Kevin D G Pfleger
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne and Perth, Australia
- Dimerix Limited, Nedlands, WA, Australia
| | - Christina Curtis
- Stanford University School of Medicine (Departments of Medicine & Genetics) and Stanford Cancer Institute, Stanford, CA, USA
| | - Bum-Kyu Lee
- Department of Biomedical Sciences, Cancer Research Center, University at Albany-State University of New York, Rensselaer, NY, USA
| | - Jonghwan Kim
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Joseph Cursons
- Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Nathan J Pavlos
- The Centre for Cell Therapy and Regenerative Medicine, School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Wojciech Biernat
- Department of Pathomorphology, Medical University of Gdansk, Gdansk, Poland
| | - Mohit Jain
- Departments of Medicine and Pharmacology, University of California, San Diego, CA, USA
| | - Andrew J Woo
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Andrew Redfern
- School of Medicine, University of Western Australia, Perth, WA, Australia
| | - Pilar Blancafort
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia.
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia.
- The Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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16
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Landin Malt A, Hogan AK, Smith CD, Madani MS, Lu X. Wnts regulate planar cell polarity via heterotrimeric G protein and PI3K signaling. J Cell Biol 2021; 219:152025. [PMID: 32805026 PMCID: PMC7659710 DOI: 10.1083/jcb.201912071] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/15/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
In the mammalian cochlea, the planar cell polarity (PCP) pathway aligns hair cell orientation along the plane of the sensory epithelium. Concurrently, multiple cell intrinsic planar polarity (referred to as iPCP) modules mediate planar polarization of the hair cell apical cytoskeleton, including the kinocilium and the V-shaped hair bundle essential for mechanotransduction. How PCP and iPCP are coordinated during development and the roles of Wnt ligands in this process remain unresolved. Here we show that genetic blockade of Wnt secretion in the cochlear epithelium resulted in a shortened cochlear duct and misoriented and misshapen hair bundles. Mechanistically, Wnts stimulate Gi activity by regulating the localization of Daple, a guanine nucleotide exchange factor (GEF) for Gαi. In turn, the Gβγ complex signals through phosphoinositide 3-kinase (PI3K) to regulate kinocilium positioning and asymmetric localizations of a subset of core PCP proteins, thereby coordinating PCP and iPCP. Thus, our results identify a putative Wnt/heterotrimeric G protein/PI3K pathway for PCP regulation.
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Affiliation(s)
- Andre Landin Malt
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA
| | - Arielle K Hogan
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA
| | - Connor D Smith
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA
| | - Maxwell S Madani
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA
| | - Xiaowei Lu
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA
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17
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Ear J, Abd El-Hafeez AA, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, McCaffrey L, Kufareva I, Sahoo D, Ghosh P. A long isoform of GIV/Girdin contains a PDZ-binding module that regulates localization and G-protein binding. J Biol Chem 2021; 296:100493. [PMID: 33675748 PMCID: PMC8042451 DOI: 10.1016/j.jbc.2021.100493] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
PDZ domains are one of the most abundant protein domains in eukaryotes and are frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and fine-tune cellular signaling. However, how such interaction affects protein function is difficult to predict and must be solved empirically. Here we describe a long isoform of the guanine nucleotide exchange factor GIV/Girdin (CCDC88A) that we named GIV-L, which is conserved throughout evolution, from invertebrates to vertebrates, and contains a PBM. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes onto cell junctions and has a PDZ interactome (as shown through annotating Human Cell Map and BioID-proximity labeling studies), which impacts GIV-L's ability to bind and activate trimeric G-protein, Gαi, through its guanine-nucleotide exchange modulator (GEM) module. This GEM module is found exclusively in vertebrates. We propose that the two functional modules in GIV may have evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analysis in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how regulation in GIV/CCDC88A transcript helps to achieve protein modularity, which allows the protein to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
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Affiliation(s)
- Jason Ear
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Biological Sciences Department, California State Polytechnic University, Pomona, California, USA.
| | - Amer Ali Abd El-Hafeez
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Suchismita Roy
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Julie Choi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Soni Khandelwal
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Luke McCaffrey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Canada; Gerald Bronfman Department of Oncology, McGill University, Montreal, Canada
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Department of Medicine, University of California San Diego, La Jolla, California, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, La Jolla, California, USA; Veterans Affairs Medical Center, La Jolla, California, USA.
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18
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Zhu Y, Delhommel F, Cordier F, Lüchow S, Mechaly A, Colcombet-Cazenave B, Girault V, Pepermans E, Bahloul A, Gautier C, Brûlé S, Raynal B, Hoos S, Haouz A, Caillet-Saguy C, Ivarsson Y, Wolff N. Deciphering the Unexpected Binding Capacity of the Third PDZ Domain of Whirlin to Various Cochlear Hair Cell Partners. J Mol Biol 2020; 432:5920-5937. [PMID: 32971111 DOI: 10.1016/j.jmb.2020.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 10/23/2022]
Abstract
Hearing is a mechanical and neurochemical process, which occurs in the hair cells of inner ear that converts the sound vibrations into electrical signals transmitted to the brain. The multi-PDZ scaffolding protein whirlin plays a critical role in the formation and function of stereocilia exposed at the surface of hair cells. In this article, we reported seven stereociliary proteins that encode PDZ binding motifs (PBM) and interact with whirlin PDZ3, where four of them are first reported. We solved the atomic resolution structures of complexes between whirlin PDZ3 and the PBMs of myosin 15a, CASK, harmonin a1 and taperin. Interestingly, the PBM of CASK and taperin are rare non-canonical PBM, which are not localized at the extreme C terminus. This large capacity to accommodate various partners could be related to the distinct functions of whirlin at different stages of the hair cell development.
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Affiliation(s)
- Yanlei Zhu
- Unité Récepteurs-Canaux, Institut Pasteur, 75015 Paris, France; Complexité du Vivant, Sorbonne Université, 75005 Paris, France
| | - Florent Delhommel
- Unité Récepteurs-Canaux, Institut Pasteur, 75015 Paris, France; Complexité du Vivant, Sorbonne Université, 75005 Paris, France
| | | | | | - Ariel Mechaly
- Plateforme de Cristallographie, Institut Pasteur, Paris, France
| | - Baptiste Colcombet-Cazenave
- Unité Récepteurs-Canaux, Institut Pasteur, 75015 Paris, France; Complexité du Vivant, Sorbonne Université, 75005 Paris, France
| | | | - Elise Pepermans
- Complexité du Vivant, Sorbonne Université, 75005 Paris, France; Unité de génétique et physiologie de l'audition, Institut Pasteur, 75015 Paris, France
| | - Amel Bahloul
- Unité de génétique et physiologie de l'audition, Institut Pasteur, 75015 Paris, France
| | - Candice Gautier
- Istituto Pasteur - Fondazione C. Bolognetti, Sapienza Università di Roma, Rome, Italy
| | - Sébastien Brûlé
- Plateforme de Biophysique Moléculaire, Institut Pasteur, Paris, France
| | - Bertrand Raynal
- Plateforme de Biophysique Moléculaire, Institut Pasteur, Paris, France
| | - Sylviane Hoos
- Plateforme de Biophysique Moléculaire, Institut Pasteur, Paris, France
| | - Ahmed Haouz
- Plateforme de Cristallographie, Institut Pasteur, Paris, France
| | | | - Ylva Ivarsson
- Department of Chemistry-BMC, Uppsala University, Sweden
| | - Nicolas Wolff
- Unité Récepteurs-Canaux, Institut Pasteur, 75015 Paris, France.
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19
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Ear J, Ali Abd El-hafeez A, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, Mccaffrey L, Kufareva I, Sahoo D, Ghosh P. Evolution of Modularity, Interactome and Functions of GIV/Girdin (CCDC88A) from Invertebrates to Vertebrates.. [DOI: 10.1101/2020.09.28.317172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractPDZ domains are one of the most abundant protein domains in eukaryotes and frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and finetune cellular signaling. Here we describe the presence of a PBM on GIV/Girdin (CCDC88A) that is conserved throughout evolution, from invertebrates to vertebrates, and is generated as a long isoform-variant in humans, which we named GIV-L. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes to the cell junctions, and has a unique PDZ-interactome, which impacts GIV-L’s ability to bind and activate trimeric G-protein, Gi through its guanine-nucleotide exchange modulator (GEM) module; the GEM module is found exclusively in vertebrates. Thus, the two functional modules in GIV evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analyses in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how GIV/CCDC88A in humans displays evolutionary flexibility in modularity, which allows the resultant isoforms to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
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20
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Abstract
The cochlea, a coiled structure located in the ventral region of the inner ear, acts as the primary structure for the perception of sound. Along the length of the cochlear spiral is the organ of Corti, a highly derived and rigorously patterned sensory epithelium that acts to convert auditory stimuli into neural impulses. The development of the organ of Corti requires a series of inductive events that specify unique cellular characteristics and axial identities along its three major axes. Here, we review recent studies of the cellular and molecular processes regulating several aspects of cochlear development, such as axial patterning, cochlear outgrowth and cellular differentiation. We highlight how the precise coordination of multiple signaling pathways is required for the successful formation of a complete organ of Corti.
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Affiliation(s)
- Elizabeth Carroll Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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21
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Cytoplasmic Dynein Functions in Planar Polarization of Basal Bodies within Ciliated Cells. iScience 2020; 23:101213. [PMID: 32535020 PMCID: PMC7300155 DOI: 10.1016/j.isci.2020.101213] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/26/2020] [Accepted: 05/27/2020] [Indexed: 12/22/2022] Open
Abstract
Despite common consensus about the importance of planar cell polarity (PCP) proteins in tissue orientation, little is known about the mechanisms used by PCP proteins to promote planar polarization of cytoskeletons within individual cells. One PCP protein Fzd6 asymmetrically localizes to the apical cell membrane of multi-ciliated ependymal cells lining the lateral ventricular (LV) wall on the side that contacts cerebrospinal fluid flow. Individual ependymal cells have planar polarized microtubules that connect ciliary basal bodies (BBs) with the cell cortex of the Fzd side to coordinate cilia orientation. Here, we report that cytoplasmic dynein is anchored to the cell cortex of the Fzd side via an adapter protein Daple that regulates microtubule dynamics. Asymmetric localization of cortical dynein generates a pulling force on dynamic microtubules connected to BBs, which in turn orients BBs toward the Fzd side. This is required for coordinated cilia orientation on the LV wall. Daple anchors cytoplasmic dynein to the cell cortex of ependymal cells on LV wall Cytoplasmic dynein is anchored to the Fzd6/Dvl1/Daple side of the cell cortex Cytoplasmic dynein functions include BB positioning and orientation Cortex-anchored dynein generates a pulling force on microtubules connected to BBs
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22
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Using Sox2 to alleviate the hallmarks of age-related hearing loss. Ageing Res Rev 2020; 59:101042. [PMID: 32173536 DOI: 10.1016/j.arr.2020.101042] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory deficit. ARHL reduces the quality of life of the growing population, setting seniors up for the enhanced mental decline. The size of the needy population, the structural deficit, and a likely research strategy for effective treatment of chronic neurosensory hearing in the elderly are needed. Although there has been profound advancement in auditory regenerative research, there remain multiple challenges to restore hearing loss. Thus, additional investigations are required, using novel tools. We propose how the (1) flat epithelium, remaining after the organ of Corti has deteriorated, can be converted to the repaired-sensory epithelium, using Sox2. This will include (2) developing an artificial gene regulatory network transmitted by (3) large viral vectors to the flat epithelium to stimulate remnants of the organ of Corti to restore hair cells. We hope to unite with our proposal toward the common goal, eventually restoring a functional human hearing organ by transforming the flat epithelial cells left after the organ of Corti loss.
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Namba T, Ishihara S. Cytoskeleton polarity is essential in determining orientational order in basal bodies of multi-ciliated cells. PLoS Comput Biol 2020; 16:e1007649. [PMID: 32084125 PMCID: PMC7055923 DOI: 10.1371/journal.pcbi.1007649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 03/04/2020] [Accepted: 01/09/2020] [Indexed: 01/16/2023] Open
Abstract
In multi-ciliated cells, directed and synchronous ciliary beating in the apical membrane occurs through appropriate configuration of basal bodies (BBs, roots of cilia). Although it has been experimentally shown that the position and orientation of BBs are coordinated by apical cytoskeletons (CSKs), such as microtubules (MTs), and planar cell polarity (PCP), the underlying mechanism for achieving the patterning of BBs is not yet understood. In this study, we propose that polarity in bundles of apical MTs play a crucial role in the patterning of BBs. First, the necessity of the polarity was discussed by theoretical consideration on the symmetry of the system. The existence of the polarity was investigated by measuring relative angles between the MTs and BBs using published experimental data. Next, a mathematical model for BB patterning was derived by combining the polarity and self-organizational ability of CSKs. In the model, BBs were treated as finite-size particles in the medium of CSKs and excluded volume effects between BBs and CSKs were taken into account. The model reproduces the various experimental observations, including normal and drug-treated phenotypes. Our model with polarity provides a coherent and testable mechanism for apical BB pattern formation. We have also discussed the implication of our study on cell chirality. Synchronous and directed ciliary beating in trachea allows transport and ejection of virus and dust from the body. This ciliary function depends on the coordinated configuration of basal bodies (root of cilia) in apical cell membrane. However, the mechanism for their formation remains unknown. In this study, we show that the polarity in apical microtubule bundles plays a significant role in the organization of basal bodies. A mathematical model incorporating polarity has been formulated which provides a coherent explanation and is able to reproduce experimental observations. We have clarified both necessity (‘why polarity is required for pattern formation’) and sufficiency (‘how polarity works for pattern formation’) of cytoskeleton polarity for correct pattering of basal bodies with verification by experimental data. This model further leads us to a possible mechanism for cellular chirality.
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Affiliation(s)
- Toshinori Namba
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo, Japan
| | - Shuji Ishihara
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo, Japan
- Universal Biology Institute, The University of Tokyo, Komaba, Tokyo, Japan
- * E-mail:
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Tyrosine-Based Signals Regulate the Assembly of Daple⋅PARD3 Complex at Cell-Cell Junctions. iScience 2020; 23:100859. [PMID: 32058970 PMCID: PMC7005484 DOI: 10.1016/j.isci.2020.100859] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/27/2019] [Accepted: 01/16/2020] [Indexed: 01/06/2023] Open
Abstract
Polarized distribution of organelles and molecules inside a cell is vital for a range of cellular processes and its loss is frequently encountered in disease. Polarization during planar cell migration is a special condition in which cellular orientation is triggered by cell-cell contact. We demonstrate that the protein Daple (CCDC88C) is a component of cell junctions in epithelial cells which serves like a cellular “compass” for establishing and maintaining contact-triggered planar polarity. Furthermore, these processes may be mediated through interaction with the polarity regulator PARD3. This interaction, mediated by Daple's PDZ-binding motif (PBM) and the third PDZ domain of PARD3, is fine-tuned by tyrosine phosphorylation on Daple's PBM by receptor and non-receptor tyrosine kinases, such as Src. Hypophosphorylation strengthens the interaction, whereas hyperphosphorylation disrupts it, thereby revealing an unexpected role of Daple as a platform for signal integration and gradient sensing for tyrosine-based signals within the planar cell polarity pathway. Daple localizes to cell junction, regulates planar cell migration Localization requires Daple's C-terminal PDZ-binding motif (PBM) The PBM binds a PDZ module of the polarity determinant PARD3 The Daple⋅PARD3 interaction is regulated by tyrosine-based signals
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Montcouquiol M, Kelley MW. Development and Patterning of the Cochlea: From Convergent Extension to Planar Polarity. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a033266. [PMID: 30617059 DOI: 10.1101/cshperspect.a033266] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Within the mammalian cochlea, sensory hair cells and supporting cells are aligned in curvilinear rows that extend along the length of the tonotopic axis. In addition, all of the cells within the epithelium are uniformly polarized across the orthogonal neural-abneural axis. Finally, each hair cell is intrinsically polarized as revealed by the presence of an asymmetrically shaped and apically localized stereociliary bundle. It has been known for some time that many of the developmental processes that regulate these patterning events are mediated, to some extent, by the core planar cell polarity (PCP) pathway. This article will review more recent work demonstrating how components of the PCP pathway interact with cytoskeletal motor proteins to regulate cochlear outgrowth. Finally, a signaling pathway originally identified for its role in asymmetric cell divisions has recently been shown to mediate several aspects of intrinsic hair cell polarity, including kinocilia migration, bundle shape, and elongation.
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Affiliation(s)
- Mireille Montcouquiol
- INSERM, Neurocentre Magendie, U1215, F-33077 Bordeaux, France.,University of Bordeaux, Neurocentre Magendie, U1215, F-33077 Bordeaux, France
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
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Tarchini B, Lu X. New insights into regulation and function of planar polarity in the inner ear. Neurosci Lett 2019; 709:134373. [PMID: 31295539 PMCID: PMC6732021 DOI: 10.1016/j.neulet.2019.134373] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/02/2019] [Accepted: 07/06/2019] [Indexed: 12/18/2022]
Abstract
Acquisition of cell polarity generates signaling and cytoskeletal asymmetry and thus underpins polarized cell behaviors during tissue morphogenesis. In epithelial tissues, both apical-basal polarity and planar polarity, which refers to cell polarization along an axis orthogonal to the apical-basal axis, are essential for epithelial morphogenesis and function. A prime example of epithelial planar polarity can be found in the auditory sensory epithelium (or organ of Corti, OC). Sensory hair cells, the sound receptors, acquire a planar polarized apical cytoskeleton which is uniformely oriented along an axis orthogonal to the longitudinal axis of the cochlear duct. Both cell-intrinsic and tissue-level planar polarity are necessary for proper perception of sound. Here we review recent insights into the novel roles and mechanisms of planar polarity signaling gained from genetic analysis in mice, focusing mainly on the OC but also with some discussions on the vestibular sensory epithelia.
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Affiliation(s)
- Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA; Department of Medicine, Tufts University, Boston, 02111, MA, USA; Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, 04469, ME, USA.
| | - Xiaowei Lu
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22908, USA.
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Intrinsic planar polarity mechanisms influence the position-dependent regulation of synapse properties in inner hair cells. Proc Natl Acad Sci U S A 2019; 116:9084-9093. [PMID: 30975754 DOI: 10.1073/pnas.1818358116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Encoding the wide range of audible sounds in the mammalian cochlea is collectively achieved by functionally diverse type I spiral ganglion neurons (SGNs) at each tonotopic position. The firing of each SGN is thought to be driven by an individual active zone (AZ) of a given inner hair cell (IHC). These AZs present distinct properties according to their position within the IHC, to some extent forming a gradient between the modiolar and the pillar IHC side. In this study, we investigated whether signaling involved in planar polarity at the apical surface can influence position-dependent AZ properties at the IHC base. Specifically, we tested the role of Gαi proteins and their binding partner LGN/Gpsm2 implicated in cytoskeleton polarization and hair cell (HC) orientation along the epithelial plane. Using high and superresolution immunofluorescence microscopy as well as patch-clamp combined with confocal Ca2+ imaging we analyzed IHCs in which Gαi signaling was blocked by Cre-induced expression of the pertussis toxin catalytic subunit (PTXa). PTXa-expressing IHCs exhibited larger CaV1.3 Ca2+-channel clusters and consequently greater Ca2+ influx at the whole-cell and single-synapse levels, which also showed a hyperpolarized shift of activation. Moreover, PTXa expression collapsed the modiolar-pillar gradients of ribbon size and maximal synaptic Ca2+ influx. Finally, genetic deletion of Gαi3 and LGN/Gpsm2 also disrupted the modiolar-pillar gradient of ribbon size. We propose a role for Gαi proteins and LGN in regulating the position-dependent AZ properties in IHCs and suggest that this signaling pathway contributes to setting up the diverse firing properties of SGNs.
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Marivin A, Morozova V, Walawalkar I, Leyme A, Kretov DA, Cifuentes D, Dominguez I, Garcia-Marcos M. GPCR-independent activation of G proteins promotes apical cell constriction in vivo. J Cell Biol 2019; 218:1743-1763. [PMID: 30948426 PMCID: PMC6504902 DOI: 10.1083/jcb.201811174] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/19/2019] [Accepted: 03/12/2019] [Indexed: 01/21/2023] Open
Abstract
Heterotrimeric G proteins are signaling switches that control organismal morphogenesis across metazoans. In invertebrates, specific GPCRs instruct G proteins to promote collective apical cell constriction in the context of epithelial tissue morphogenesis. In contrast, tissue-specific factors that instruct G proteins during analogous processes in vertebrates are largely unknown. Here, we show that DAPLE, a non-GPCR protein linked to human neurodevelopmental disorders, is expressed specifically in the neural plate of Xenopus laevis embryos to trigger a G protein signaling pathway that promotes apical cell constriction during neurulation. DAPLE localizes to apical cell-cell junctions in the neuroepithelium, where it activates G protein signaling to drive actomyosin-dependent apical constriction and subsequent bending of the neural plate. This function is mediated by a Gα-binding-and-activating (GBA) motif that was acquired by DAPLE in vertebrates during evolution. These findings reveal that regulation of tissue remodeling during vertebrate development can be driven by an unconventional mechanism of heterotrimeric G protein activation that operates in lieu of GPCRs.
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Affiliation(s)
- Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Veronika Morozova
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Isha Walawalkar
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Anthony Leyme
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Dmitry A Kretov
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Daniel Cifuentes
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Isabel Dominguez
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
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Par3 is essential for the establishment of planar cell polarity of inner ear hair cells. Proc Natl Acad Sci U S A 2019; 116:4999-5008. [PMID: 30814219 DOI: 10.1073/pnas.1816333116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the inner ear sensory epithelia, stereociliary hair bundles atop sensory hair cells are mechanosensory apparatus with planar polarized structure and orientation. This is established during development by the concerted action of tissue-level, intercellular planar cell polarity (PCP) signaling and a hair cell-intrinsic, microtubule-mediated machinery. However, how various polarity signals are integrated during hair bundle morphogenesis is poorly understood. Here, we show that the conserved cell polarity protein Par3 is essential for planar polarization of hair cells. Par3 deletion in the inner ear disrupted cochlear outgrowth, hair bundle orientation, kinocilium positioning, and basal body planar polarity, accompanied by defects in the organization and cortical attachment of hair cell microtubules. Genetic mosaic analysis revealed that Par3 functions both cell-autonomously and cell-nonautonomously to regulate kinocilium positioning and hair bundle orientation. At the tissue level, intercellular PCP signaling regulates the asymmetric localization of Par3, which in turn maintains the asymmetric localization of the core PCP protein Vangl2. Mechanistically, Par3 interacts with and regulates the localization of Tiam1 and Trio, which are guanine nucleotide exchange factors (GEFs) for Rac, thereby stimulating Rac-Pak signaling. Finally, constitutively active Rac1 rescued the PCP defects in Par3-deficient cochleae. Thus, a Par3-GEF-Rac axis mediates both tissue-level and hair cell-intrinsic PCP signaling.
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Pelaseyed T, Bretscher A. Regulation of actin-based apical structures on epithelial cells. J Cell Sci 2018; 131:131/20/jcs221853. [PMID: 30333133 DOI: 10.1242/jcs.221853] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cells of transporting epithelia are characterized by the presence of abundant F-actin-based microvilli on their apical surfaces. Likewise, auditory hair cells have highly reproducible rows of apical stereocilia (giant microvilli) that convert mechanical sound into an electrical signal. Analysis of mutations in deaf patients has highlighted the critical components of tip links between stereocilia, and related structures that contribute to the organization of microvilli on epithelial cells have been found. Ezrin/radixin/moesin (ERM) proteins, which are activated by phosphorylation, provide a critical link between the plasma membrane and underlying actin cytoskeleton in surface structures. Here, we outline recent insights into how microvilli and stereocilia are built, and the roles of tip links. Furthermore, we highlight how ezrin is locally regulated by phosphorylation, and that this is necessary to maintain polarity. Localized phosphorylation is achieved through an intricate coincidence detection mechanism that requires the membrane lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the apically localized ezrin kinase, lymphocyte-oriented kinase (LOK, also known as STK10) or Ste20-like kinase (SLK). We also discuss how ezrin-binding scaffolding proteins regulate microvilli and how, despite these significant advances, it remains to be discovered how the cell polarity program ultimately interfaces with these processes.
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Affiliation(s)
- Thaher Pelaseyed
- Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden
| | - Anthony Bretscher
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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