1
|
Hapak SM, Rothlin CV, Ghosh S. PAR3-PAR6-atypical PKC polarity complex proteins in neuronal polarization. Cell Mol Life Sci 2018; 75:2735-2761. [PMID: 29696344 PMCID: PMC11105418 DOI: 10.1007/s00018-018-2828-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/03/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023]
Abstract
Polarity is a fundamental feature of cells. Protein complexes, including the PAR3-PAR6-aPKC complex, have conserved roles in establishing polarity across a number of eukaryotic cell types. In neurons, polarity is evident as distinct axonal versus dendritic domains. The PAR3, PAR6, and aPKC proteins also play important roles in neuronal polarization. During this process, either aPKC kinase activity, the assembly of the PAR3-PAR6-aPKC complex or the localization of these proteins is regulated downstream of a number of signaling pathways. In turn, the PAR3, PAR6, and aPKC proteins control various effector molecules to establish neuronal polarity. Herein, we discuss the many signaling mechanisms and effector functions that have been linked to PAR3, PAR6, and aPKC during the establishment of neuronal polarity.
Collapse
Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN, 55455, USA.
| | - Carla V Rothlin
- Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT, 06520, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT, 06511, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| |
Collapse
|
2
|
Affiliation(s)
| | | | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case
Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106-4965,
United States
| |
Collapse
|
3
|
Sticking together the Crumbs - an unexpected function for an old friend. Nat Rev Mol Cell Biol 2013; 14:307-14. [PMID: 23609509 DOI: 10.1038/nrm3568] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell polarity and cell-cell junctions have pivotal roles in organizing cells into tissues and in mediating cell-cell communication. The transmembrane protein Crumbs has a well-established role in the maintenance of epithelial polarity, and it can also regulate signalling via the Notch and Hippo pathways to influence tissue growth. The functions of Crumbs in epithelial polarity and Hippo-mediated growth depend on its short intracellular domain. Recent evidence now points to a conserved and fundamental role for the extracellular domain of Crumbs in mediating homophilic Crumbs-Crumbs interactions at cell-cell junctions.
Collapse
|
4
|
Letizia A, Ricardo S, Moussian B, Martín N, Llimargas M. A functional role of the extracellular domain of Crumbs in cell architecture and apicobasal polarity. J Cell Sci 2013; 126:2157-63. [PMID: 23525000 DOI: 10.1242/jcs.122382] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Regulated cell shape changes in epithelial cells, which contribute to most organs and tissues, are at the basis of morphogenesis. Crumbs (Crb) is an essential apical determinant controlling epithelial apicobasal polarity. Here we provide evidence for a novel role of Crb apical localisation and stabilisation in controlling cell shape through apical domain organisation and adherens junction positioning. We find that Crb apical stabilisation requires the extracellular domain. In vivo results from Drosophila suggest that the extracellular domain assists Crb apical stabilisation by mediating Crb-Crb interactions at opposing cell membranes. We further confirm Crb-Crb extracellular interactions by showing that the extracellular domain of Crb is sufficient to promote cell aggregation in vitro. Furthermore, we report that Crb apical stabilisation mediated by the extracellular domain is also required for maintenance of Crb apicobasal polarity. Our results provide new insights into the mechanisms of apicobasal polarity and the cellular mechanisms of tissue architecture.
Collapse
Affiliation(s)
- Annalisa Letizia
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | | | | | | | | |
Collapse
|
5
|
Positive feedback and mutual antagonism combine to polarize Crumbs in the Drosophila follicle cell epithelium. Curr Biol 2012; 22:1116-22. [PMID: 22658591 DOI: 10.1016/j.cub.2012.04.020] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 03/06/2012] [Accepted: 04/11/2012] [Indexed: 12/15/2022]
Abstract
Epithelial tissues are composed of polarized cells with distinct apical and basolateral membrane domains. In the Drosophila ovarian follicle cell epithelium, apical membranes are specified by Crumbs (Crb), Stardust (Sdt), and the aPKC-Par6-cdc42 complex. Basolateral membranes are specified by Lethal giant larvae (Lgl), Discs large (Dlg), and Scribble (Scrib). Apical and basolateral determinants are known to act in a mutually antagonistic fashion, but it remains unclear how this interaction generates polarity. We have built a computer model of apicobasal polarity that suggests that the combination of positive feedback among apical determinants plus mutual antagonism between apical and basal determinants is essential for polarization. In agreement with this model, in vivo experiments define a positive feedback loop in which Crb self-recruits via Crb-Crb extracellular domain interactions, recruitment of Sdt-aPKC-Par6-cdc42, aPKC phosphorylation of Crb, and recruitment of Expanded (Ex) and Kibra (Kib) to prevent endocytic removal of Crb from the plasma membrane. Lgl antagonizes the operation of this feedback loop, explaining why apical determinants do not normally spread into the basolateral domain. Once Crb is removed from the plasma membrane, it undergoes recycling via Rab11 endosomes. Our results provide a dynamic model for understanding how epithelial polarity is maintained in Drosophila follicle cells.
Collapse
|
6
|
Galy A, Schenck A, Sahin HB, Qurashi A, Sahel JA, Diebold C, Giangrande A. CYFIP dependent actin remodeling controls specific aspects of Drosophila eye morphogenesis. Dev Biol 2011; 359:37-46. [PMID: 21884694 DOI: 10.1016/j.ydbio.2011.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/11/2011] [Accepted: 08/15/2011] [Indexed: 12/20/2022]
Abstract
Cell rearrangements shape organs and organisms using molecular pathways and cellular processes that are still poorly understood. Here we investigate the role of the Actin cytoskeleton in the formation of the Drosophila compound eye, which requires extensive remodeling and coordination between different cell types. We show that CYFIP/Sra-1, a member of the WAVE/SCAR complex and regulator of Actin remodeling, controls specific aspects of eye architecture: rhabdomere extension, rhabdomere terminal web organization, adherens junctions, retina depth and basement membrane integrity. We demonstrate that some phenotypes manifest independently, due to defects in different cell types. Mutations in WAVE/SCAR and in ARP2/3 complex subunits but not in WASP, another major regulator of Actin nucleation, phenocopy CYFIP defects. Thus, the CYFIP-SCAR-ARP2/3 pathway orchestrates specific tissue remodeling processes.
Collapse
Affiliation(s)
- Anne Galy
- Fovea-Pharmaceuticals, Institut de la vision, 17 rue Moreau 75012 Paris, France
| | - Annette Schenck
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Donders Institute for Brain, Cognition and Behaviour & Radboud University Nijmegen Medical Center, 6525 GA Nijmegen, The Netherlands.
| | - H Bahar Sahin
- Department of Molecular Biology and Genetics, Bogazici University, Bebek, Istanbul, Turkey
| | - Abrar Qurashi
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - José-Alain Sahel
- INSERM, U968, Université Pierre et Marie Curie-Paris 6, UM80, Institut de la Vision, CNRS, UMR-7210, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France; Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Céline Diebold
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/UDS, BP 10142, 67404 Illkirch, CU de Strasbourg, France
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/UDS, BP 10142, 67404 Illkirch, CU de Strasbourg, France.
| |
Collapse
|
7
|
Hsu YC, Jensen AM. Multiple domains in the Crumbs Homolog 2a (Crb2a) protein are required for regulating rod photoreceptor size. BMC Cell Biol 2010; 11:60. [PMID: 20670434 PMCID: PMC2927502 DOI: 10.1186/1471-2121-11-60] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 07/29/2010] [Indexed: 12/26/2022] Open
Abstract
Background Vertebrate retinal photoreceptors are morphologically complex cells that have two apical regions, the inner segment and the outer segment. The outer segment is a modified cilium and is continuously regenerated throughout life. The molecular and cellular mechanisms that underlie vertebrate photoreceptor morphogenesis and the maintenance of the outer segment are largely unknown. The Crumbs (Crb) complex is a key regulator of apical membrane identity and size in epithelia and in Drosophila photoreceptors. Mutations in the human gene CRUMBS HOMOLOG 1 (CRB1) are associated with early and severe vision loss. Drosophila Crumbs and vertebrate Crb1 and Crumbs homolog 2 (Crb2) proteins are structurally similar, all are single pass transmembrane proteins with a large extracellular domain containing multiple laminin- and EGF-like repeats and a small intracellular domain containing a FERM-binding domain and a PDZ-binding domain. In order to begin to understand the role of the Crb family of proteins in vertebrate photoreceptors we generated stable transgenic zebrafish in which rod photoreceptors overexpress full-length Crb2a protein and several other Crb2a constructs engineered to lack specific domains. Results We examined the localization of Crb2a constructs and their effects on rod morphology. We found that only the full-length Crb2a protein approximated the normal localization of Crb2a protein apical to adherens junctions in the photoreceptor inner segment. Several Crb2a construct proteins localized abnormally to the outer segment and one construct localized abnormally to the cell body. Overexpression of full-length Crb2a greatly increased inner segment size while expression of several other constructs increased outer segment size. Conclusions Our observations suggest that particular domains in Crb2a regulate its localization and thus may regulate its regionalized function. Our results also suggest that the PDZ-binding domain in Crb2a might bring a protein(s) into the Crb complex that alters the function of the FERM-binding domain.
Collapse
Affiliation(s)
- Ya-Chu Hsu
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | | |
Collapse
|
8
|
Richardson ECN, Pichaud F. Crumbs is required to achieve proper organ size control during Drosophila head development. Development 2010; 137:641-50. [PMID: 20110329 DOI: 10.1242/dev.041913] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Crumbs (Crb) is a conserved apical polarity determinant required for zonula adherens specification and remodelling during Drosophila development. Interestingly, crb function in maintaining apicobasal polarity appears largely dispensable in primary epithelia such as the imaginal discs. Here, we show that crb function is not required for maintaining epithelial integrity during the morphogenesis of the Drosophila head and eye. However, although crb mutant heads are properly developed, they are also significantly larger than their wild-type counterparts. We demonstrate that in the eye, this is caused by an increase in cell proliferation that can be attributed to an increase in ligand-dependent Notch (N) signalling. Moreover, we show that in crb mutant cells, ectopic N activity correlates with an increase in N and Delta endocytosis. These data indicate a role for Crb in modulating endocytosis at the apical epithelial plasma membrane, which we demonstrate is independent of Crb function in apicobasal polarity. Overall, our work reveals a novel function for Crb in limiting ligand-dependent transactivation of the N receptor at the epithelial cell membrane.
Collapse
Affiliation(s)
- Emily C N Richardson
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London, UK
| | | |
Collapse
|
9
|
Walther RF, Pichaud F. Immunofluorescent staining and imaging of the pupal and adult Drosophila visual system. Nat Protoc 2007; 1:2635-42. [PMID: 17406519 DOI: 10.1038/nprot.2006.379] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This immunofluorescence protocol can be used to assay cell morphology, cell positioning and subcellular localization of proteins in the fly eye at stages of development from early pupation to adult. The protocol includes the following procedures: collecting and developmentally staging Drosophila pupae, dissecting fly eyes at defined stages of development, immunostaining of retina and preparing visual system samples (i.e., retina and optic lobe) for confocal microscopy. It is supplemented with images of key dissection steps, guidelines for troubleshooting and examples of data obtained using these methods. Overall, this protocol takes up to 9 d to complete. The amount of hands-on time required on each day varies, ranging from 30 min to several hours depending on the number of stages and/or genotypes one wishes to study.
Collapse
Affiliation(s)
- Rhian F Walther
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | | |
Collapse
|
10
|
Pinal N, Goberdhan DCI, Collinson L, Fujita Y, Cox IM, Wilson C, Pichaud F. Regulated and polarized PtdIns(3,4,5)P3 accumulation is essential for apical membrane morphogenesis in photoreceptor epithelial cells. Curr Biol 2006; 16:140-9. [PMID: 16431366 DOI: 10.1016/j.cub.2005.11.068] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 11/09/2005] [Accepted: 11/23/2005] [Indexed: 12/31/2022]
Abstract
BACKGROUND In a specialized epithelial cell such as the Drosophila photoreceptor, a conserved set of proteins is essential for the establishment of polarity, its maintenance, or both--in Drosophila, these proteins include the apical factors Bazooka, D-atypical protein kinase C, and D-Par6 together with D-Ecadherin. However, little is known about the mechanisms by which such apical factors might regulate the differentiation of the apical membrane into functional domains such as an apical-most stack of microvilli or more lateral sub-apical membrane. RESULTS We show that in photoreceptors Bazooka (D-Par3) recruits the tumor suppressor lipid phosphatase PTEN to developing cell-cell junctions (Zonula Adherens, za). za-localized PTEN controls the spatially restricted accumulation of optimum levels of the lipid PtdIns(3,4,5)P3 within the apical membrane domain. This in turn finely tunes activation of Akt1, a process essential for proper morphogenesis of the light-gathering organelle, consisting of a stack of F-actin rich microvilli within the apical membrane. CONCLUSIONS Spatially localized PtdIns(3,4,5)P3 mediates directional sensing during neutrophil and Dictyostelium chemotaxis. We conclude that a conserved mechanism also operates during photoreceptor epithelial cell morphogenesis in order to achieve normal differentiation of the apical membrane.
Collapse
Affiliation(s)
- Noelia Pinal
- Medical Research Council Laboratory for Molecular Cell Biology and Cell Biology Unit, Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
11
|
Mollereau B, Domingos PM. Photoreceptor differentiation in Drosophila: from immature neurons to functional photoreceptors. Dev Dyn 2005; 232:585-92. [PMID: 15704118 DOI: 10.1002/dvdy.20271] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
How a pool of equipotent cells acquires a multitude of distinct fates is a major question in developmental biology. The study of photoreceptor (PR) cell differentiation in Drosophila has been used to address this question. PR differentiation is a process that extends over a period of 5 days: It begins in the larval eye imaginal disc when PRs are recruited and commit to particular PR fates, and it culminates in the pupal eye disc with the morphogenesis of the rhabdomeres and the initiation of rhodopsin expression. Several models for PR specification agree that the Ras and Notch signaling pathways are important for the specification of different PR subtypes (Freeman [1997] Development 124:261-270; Cooper and Bray [2000] Curr. Biol. 10:1507-1510; Tomlinson and Struhl [2001] Mol. Cell. 7:487-495). In the first part of this review, we briefly describe the different signaling pathways and transcription factors required for the specification and differentiation of the different PR subtypes in the larval eye disc. In the second part, we review the roles of several transcription factors, which are required for the terminal photoreceptor differentiation and rhodopsin expression.
Collapse
Affiliation(s)
- Bertrand Mollereau
- Strang Laboratory of Cancer Research, The Rockefeller University, New York, New York 10021, USA.
| | | |
Collapse
|
12
|
Williams JA, MacIver B, Klipfell EA, Thomas GH. The C-terminal domain ofDrosophilaβHeavy-spectrin exhibits autonomous membrane association and modulates membrane area. J Cell Sci 2004; 117:771-82. [PMID: 14734656 DOI: 10.1242/jcs.00922] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Current models of cell polarity invoke asymmetric cues that reorganize the secretory apparatus to induce polarized protein delivery. An important step in this process is the stabilization of the protein composition in each polarized membrane domain. The spectrin-based membrane skeleton is thought to contribute to such stabilization by increasing the half-life of many proteins at the cell surface. Genetic evidence is consistent with a negative role for Drosophila βHeavy-spectrin in endocytosis, but the inhibitory mechanism has not been elucidated. Here, we investigated the membrane binding properties of the C-terminal nonrepetitive domain of βHeavy-spectrin through its in vivo expression in transgenic flies. We found that this region is a membrane-association domain that requires a pleckstrin homology domain for full activity, and we showed for the first time that robust membrane binding by such a C-terminal domain requires additional contributions outside the pleckstrin homology. In addition, we showed that expression of the βHeavy-spectrin C-terminal domain has a potent effect on epithelial morphogenesis. This effect is associated with its ability to induce an expansion in plasma membrane surface area. The membrane expansions adopt a very specific bi-membrane structure that sequesters both the C-terminal domain and the endocytic protein dynamin. Our data provide supporting evidence for the inhibition of endocytosis by βHeavy-spectrin, and suggest that the C-terminal domain mediates this effect through interaction with the endocytic machinery. Spectrin may be an active partner in the stabilization of polarized membrane domains.
Collapse
Affiliation(s)
- Janice A Williams
- Department of Biology, Department of Biochemistry and Molecular Biology, Eberly College of Science, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | | | |
Collapse
|