1
|
Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR protein caps orient the mitotic spindle in C. elegans early embryos. Curr Biol 2023; 33:4312-4329.e6. [PMID: 37729910 PMCID: PMC10615879 DOI: 10.1016/j.cub.2023.08.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/24/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases, it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact-free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, isolated single blastomeres lacking cell contacts are able to break symmetry and form PAR-3/atypical protein kinase C (aPKC) caps. Polarity caps form independently of actomyosin flows and microtubules and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
Collapse
Affiliation(s)
- Naomi J Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Nadia I Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Daniel J Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA.
| |
Collapse
|
2
|
Naturale VF, Pickett MA, Feldman JL. Persistent cell contacts enable E-cadherin/HMR-1- and PAR-3-based symmetry breaking within a developing C. elegans epithelium. Dev Cell 2023; 58:1830-1846.e12. [PMID: 37552986 PMCID: PMC10592304 DOI: 10.1016/j.devcel.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 05/10/2023] [Accepted: 07/17/2023] [Indexed: 08/10/2023]
Abstract
Tissue-wide patterning is essential to multicellular development, requiring cells to individually generate polarity axes and coordinate them in space and time with neighbors. Using the C. elegans intestinal epithelium, we identified a patterning mechanism that is informed by cell contact lifetime asymmetry and executed via the scaffolding protein PAR-3 and the transmembrane protein E-cadherin/HMR-1. Intestinal cells break symmetry as PAR-3 and HMR-1 recruit apical determinants into punctate "local polarity complexes" (LPCs) at homotypic contacts. LPCs undergo an HMR-1-based migration to a common midline, thereby establishing tissue-wide polarity. Thus, symmetry breaking results from PAR-3-dependent intracellular polarization coupled to HMR-1-based tissue-level communication, which occurs through a non-adhesive signaling role for HMR-1. Differential lifetimes between homotypic and heterotypic cell contacts are created by neighbor exchanges and oriented divisions, patterning where LPCs perdure and thereby breaking symmetry. These cues offer a logical and likely conserved framework for how epithelia without obvious molecular asymmetries can polarize.
Collapse
Affiliation(s)
| | - Melissa A Pickett
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Biological Sciences, San José State University, San José, CA 95192, USA
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
3
|
McIntyre DC, Nance J. Niche cells regulate primordial germ cell quiescence in response to basement membrane signaling. Development 2023; 150:dev201640. [PMID: 37497562 PMCID: PMC10445801 DOI: 10.1242/dev.201640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023]
Abstract
Stem cell quiescence, proliferation and differentiation are controlled by interactions with niche cells and a specialized extracellular matrix called basement membrane (BM). Direct interactions with adjacent BM are known to regulate stem cell quiescence; however, it is less clear how niche BM relays signals to stem cells that it does not contact. Here, we examine how niche BM regulates Caenorhabditis elegans primordial germ cells (PGCs). BM regulates PGC quiescence even though PGCs are enwrapped by somatic niche cells and do not contact the BM; this can be demonstrated by depleting laminin, which causes normally quiescent embryonic PGCs to proliferate. We show that following laminin depletion, niche cells relay proliferation-inducing signals from the gonadal BM to PGCs via integrin receptors. Disrupting the BM proteoglycan perlecan blocks PGC proliferation when laminin is depleted, indicating that laminin functions to inhibit a proliferation-inducing signal originating from perlecan. Reducing perlecan levels in fed larvae hampers germline growth, suggesting that BM signals regulate germ cell proliferation under physiological conditions. Our results reveal how BM signals can regulate stem cell quiescence indirectly, by activating niche cell integrin receptors.
Collapse
Affiliation(s)
- Daniel C. McIntyre
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, NY 10016, USA
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
- University of Virginia, Department of Biology, 90 Geldard Drive, Physical Life Science Building Room 318, Charlottesville, VA 22904, USA
| | - Jeremy Nance
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, NY 10016, USA
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
| |
Collapse
|
4
|
Zhang N, Zhang H, Khan LA, Jafari G, Eun Y, Membreno E, Gobel V. The biosynthetic-secretory pathway, supplemented by recycling routes, determines epithelial membrane polarity. SCIENCE ADVANCES 2023; 9:eade4620. [PMID: 37379377 PMCID: PMC10306302 DOI: 10.1126/sciadv.ade4620] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 05/24/2023] [Indexed: 06/30/2023]
Abstract
In prevailing epithelial polarity models, membrane-based polarity cues (e.g., the partitioning-defective PARs) position apicobasal cellular membrane domains. Intracellular vesicular trafficking expands these domains by sorting polarized cargo toward them. How the polarity cues themselves are polarized in epithelia and how sorting confers long-range apicobasal directionality to vesicles is still unclear. Here, a systems-based approach using two-tiered C. elegans genomics-genetics screens identifies trafficking molecules that are not implicated in apical sorting yet polarize apical membrane and PAR complex components. Live tracking of polarized membrane biogenesis indicates that the biosynthetic-secretory pathway, linked to recycling routes, is asymmetrically oriented toward the apical domain during this domain's biosynthesis, and that this directionality is regulated upstream of PARs and independent of polarized target membrane domains. This alternative mode of membrane polarization could offer solutions to open questions in current models of epithelial polarity and polarized trafficking.
Collapse
Affiliation(s)
- Nan Zhang
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
- Key Laboratory of Zoonosis Research by the Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Hongjie Zhang
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Liakot A. Khan
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| | - Gholamali Jafari
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| | - Yong Eun
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
- Department of Medicine, NYC Health & Hospitals/Harlem, Columbia University, New York, NY, USA
| | - Edward Membreno
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| | - Verena Gobel
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
5
|
Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR-3 caps orient the mitotic spindle in C. elegans early embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.27.534341. [PMID: 37034756 PMCID: PMC10081169 DOI: 10.1101/2023.03.27.534341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, apical PAR-3 can form polarity caps independently of actomyosin flows and the small GTPase CDC-42, and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
Collapse
Affiliation(s)
- Naomi J. Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Nadia I. Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Daniel J. Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| |
Collapse
|
6
|
Liu A, Ouyang X, Wang Z, Dong B. ELMOD3-Rab1A-Flotillin2 cascade regulates lumen formation via vesicle trafficking in Ciona notochord. Open Biol 2023; 13:220367. [PMID: 36918025 PMCID: PMC10014252 DOI: 10.1098/rsob.220367] [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: 03/16/2023] Open
Abstract
Lumen development is a crucial phase in tubulogenesis, although its molecular mechanisms are largely unknown. In this study, we discovered an ELMO domain-containing 3 (ELMOD3), which belongs to ADP-ribosylation factor GTPase-activating protein family, was necessary to form the notochord lumen in Ciona larvae. We demonstrated that ELMOD3 interacted with lipid raft protein Flotillin2 and regulated its subcellular localization. The loss-of-function of Flotillin2 prevented notochord lumen formation. Furthermore, we found that ELMOD3 also interacted with Rab1A, which is the regulatory GTPase for vesicle trafficking and located at the notochord cell surface. Rab1A mutations arrested the lumen formation, phenocopying the loss-of-function of ELMOD3 and Flotillin2. Our findings further suggested that Rab1A interactions influenced Flotillin2 localization. We thus identified a unique pathway in which ELMOD3 interacted with Rab1A, which controlled the Flotillin2-mediated vesicle trafficking from cytoplasm to apical membrane, required for Ciona notochord lumen formation.
Collapse
Affiliation(s)
- Amei Liu
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Xiuke Ouyang
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Zhuqing Wang
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Bo Dong
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
- Laoshan Laboratory, Qingdao 266237, People's Republic of China
| |
Collapse
|
7
|
Shaping subcellular tubes through vesicle trafficking: Common and distinct pathways. Semin Cell Dev Biol 2023; 133:74-82. [PMID: 35365398 DOI: 10.1016/j.semcdb.2022.03.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/23/2022]
Abstract
Cells with subcellular lumens form some of the most miniature tubes in the tubular organs of animals. These are often crucial components of the system, executing functions at remote body locations. Unlike tubes formed by intercellular or autocellular junctions, the cells with junctionless subcellular lumens face unique challenges in modifying the cell shape and plasma membrane organization to incorporate a membrane-bound tube within, often associated with dramatic cellular growth and extensions. Results in the recent years have shown that membrane dynamics, including both the primary delivery and recycling, is crucial in providing the cell with the flexibility to face these challenges. A significant portion of this information has come from two in vivo invertebrate models; the Drosophila tracheal terminal cells and the C. elegans excretory cell. This review focuses on the data obtained from these systems in the recent past about how trafficking pathways influence subcellular tube and branching morphogenesis. Given that such tubes occur in vertebrate vasculature, these insights are relevant to human health, and we contrast our conclusions with the less understood subcellular tubes of angiogenesis.
Collapse
|
8
|
Naturale VF, Pickett MA, Feldman JL. Context matters: Lessons in epithelial polarity from the Caenorhabditis elegans intestine and other tissues. Curr Top Dev Biol 2023; 154:37-71. [PMID: 37100523 DOI: 10.1016/bs.ctdb.2023.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Epithelia are tissues with diverse morphologies and functions across metazoans, ranging from vast cell sheets encasing internal organs to internal tubes facilitating nutrient uptake, all of which require establishment of apical-basolateral polarity axes. While all epithelia tend to polarize the same components, how these components are deployed to drive polarization is largely context-dependent and likely shaped by tissue-specific differences in development and ultimate functions of polarizing primordia. The nematode Caenorhabditis elegans (C. elegans) offers exceptional imaging and genetic tools and possesses unique epithelia with well-described origins and roles, making it an excellent model to investigate polarity mechanisms. In this review, we highlight the interplay between epithelial polarization, development, and function by describing symmetry breaking and polarity establishment in a particularly well-characterized epithelium, the C. elegans intestine. We compare intestinal polarization to polarity programs in two other C. elegans epithelia, the pharynx and epidermis, correlating divergent mechanisms with tissue-specific differences in geometry, embryonic environment, and function. Together, we emphasize the importance of investigating polarization mechanisms against the backdrop of tissue-specific contexts, while also underscoring the benefits of cross-tissue comparisons of polarity.
Collapse
Affiliation(s)
- Victor F Naturale
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Melissa A Pickett
- Department of Biology, Stanford University, Stanford, CA, United States; Department of Biological Sciences, San José State University, San José, CA, United States
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, CA, United States.
| |
Collapse
|
9
|
Pickett MA, Sallee MD, Cote L, Naturale VF, Akpinaroglu D, Lee J, Shen K, Feldman JL. Separable mechanisms drive local and global polarity establishment in the Caenorhabditiselegans intestinal epithelium. Development 2022; 149:dev200325. [PMID: 36264257 PMCID: PMC9845746 DOI: 10.1242/dev.200325] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 10/06/2022] [Indexed: 11/17/2022]
Abstract
Apico-basolateral polarization is essential for epithelial cells to function as selective barriers and transporters, and to provide mechanical resilience to organs. Epithelial polarity is established locally, within individual cells to establish distinct apical, junctional and basolateral domains, and globally, within a tissue where cells coordinately orient their apico-basolateral axes. Using live imaging of endogenously tagged proteins and tissue-specific protein depletion in the Caenorhabditiselegans embryonic intestine, we found that local and global polarity establishment are temporally and genetically separable. Local polarity is initiated prior to global polarity and is robust to perturbation. PAR-3 is required for global polarization across the intestine but local polarity can arise in its absence, as small groups of cells eventually established polarized domains in PAR-3-depleted intestines in a HMR-1 (E-cadherin)-dependent manner. Despite the role of PAR-3 in localizing PKC-3 to the apical surface, we additionally found that PAR-3 and PKC-3/aPKC have distinct roles in the establishment and maintenance of local and global polarity. Taken together, our results indicate that different mechanisms are required for local and global polarity establishment in vivo.
Collapse
Affiliation(s)
- Melissa A. Pickett
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Department of Biological Sciences, San Jose State University, San Jose, CA 95112, USA
| | - Maria D. Sallee
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Lauren Cote
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | | | - Joo Lee
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | |
Collapse
|
10
|
Agarwal P, Shemesh T, Zaidel-Bar R. Directed cell invasion and asymmetric adhesion drive tissue elongation and turning in C. elegans gonad morphogenesis. Dev Cell 2022; 57:2111-2126.e6. [PMID: 36049484 DOI: 10.1016/j.devcel.2022.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/03/2022] [Accepted: 08/09/2022] [Indexed: 12/15/2022]
Abstract
Development of the C. elegans gonad has long been studied as a model of organogenesis driven by collective cell migration. A somatic cell named the distal tip cell (DTC) is thought to serve as the leader of following germ cells; yet, the mechanism for DTC propulsion and maneuvering remains elusive. Here, we demonstrate that the DTC is not self-propelled but rather is pushed by the proliferating germ cells. Proliferative pressure pushes the DTC forward, against the resistance of the basement membrane in front. The DTC locally secretes metalloproteases that degrade the impeding membrane, resulting in gonad elongation. Turning of the gonad is achieved by polarized DTC-matrix adhesions. The asymmetrical traction results in a bending moment on the DTC. Src and Cdc42 regulate integrin adhesion polarity, whereas an external netrin signal determines DTC orientation. Our findings challenge the current view of DTC migration and offer a distinct framework to understand organogenesis.
Collapse
Affiliation(s)
- Priti Agarwal
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tom Shemesh
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| |
Collapse
|
11
|
Barrera-Velázquez M, Ríos-Barrera LD. Crosstalk between basal extracellular matrix adhesion and building of apical architecture during morphogenesis. Biol Open 2021; 10:bio058760. [PMID: 34842274 PMCID: PMC8649640 DOI: 10.1242/bio.058760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tissues build complex structures like lumens and microvilli to carry out their functions. Most of the mechanisms used to build these structures rely on cells remodelling their apical plasma membranes, which ultimately constitute the specialised compartments. In addition to apical remodelling, these shape changes also depend on the proper attachment of the basal plasma membrane to the extracellular matrix (ECM). The ECM provides cues to establish apicobasal polarity, and it also transduces forces that allow apical remodelling. However, physical crosstalk mechanisms between basal ECM attachment and the apical plasma membrane remain understudied, and the ones described so far are very diverse, which highlights the importance of identifying the general principles. Here, we review apicobasal crosstalk of two well-established models of membrane remodelling taking place during Drosophila melanogaster embryogenesis: amnioserosa cell shape oscillations during dorsal closure and subcellular tube formation in tracheal cells. We discuss how anchoring to the basal ECM affects apical architecture and the mechanisms that mediate these interactions. We analyse this knowledge under the scope of other morphogenetic processes and discuss what aspects of apicobasal crosstalk may represent widespread phenomena and which ones are used to build subsets of specialised compartments.
Collapse
Affiliation(s)
- Mariana Barrera-Velázquez
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510, Mexico
- Undergraduate Program on Genomic Sciences, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico
| | - Luis Daniel Ríos-Barrera
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510, Mexico
| |
Collapse
|
12
|
Sallee MD, Pickett MA, Feldman JL. Apical PAR complex proteins protect against programmed epithelial assaults to create a continuous and functional intestinal lumen. eLife 2021; 10:64437. [PMID: 34137371 PMCID: PMC8245128 DOI: 10.7554/elife.64437] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 06/16/2021] [Indexed: 12/16/2022] Open
Abstract
Sustained polarity and adhesion of epithelial cells is essential for the protection of our organs and bodies, and this epithelial integrity emerges during organ development amidst numerous programmed morphogenetic assaults. Using the developing Caenorhabditis elegans intestine as an in vivo model, we investigated how epithelia maintain their integrity through cell division and elongation to build a functional tube. Live imaging revealed that apical PAR complex proteins PAR-6/Par6 and PKC-3/aPkc remained apical during mitosis while apical microtubules and microtubule-organizing center (MTOC) proteins were transiently removed. Intestine-specific depletion of PAR-6, PKC-3, and the aPkc regulator CDC-42/Cdc42 caused persistent gaps in the apical MTOC as well as in other apical and junctional proteins after cell division and in non-dividing cells that elongated. Upon hatching, gaps coincided with luminal constrictions that blocked food, and larvae arrested and died. Thus, the apical PAR complex maintains apical and junctional continuity to construct a functional intestinal tube.
Collapse
|
13
|
Parallel Rap1>RalGEF>Ral and Ras signals sculpt the C. elegans nervous system. Dev Biol 2021; 477:37-48. [PMID: 33991533 DOI: 10.1016/j.ydbio.2021.05.004] [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: 01/27/2021] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 11/23/2022]
Abstract
Ras is the most commonly mutated oncogene in humans and uses three oncogenic effectors: Raf, PI3K, and RalGEF activation of Ral. Understanding the importance of RalGEF>Ral signaling in cancer is hampered by the paucity of knowledge about their function in animal development, particularly in cell movements. We found that mutations that disrupt function of RalGEF or Ral enhance migration phenotypes of mutants for genes with established roles in cell migration. We used as a model the migration of the canal associated neurons (CANs), and validated our results in HSN cell migration, neurite guidance, and general animal locomotion. These functions of RalGEF and Ral are specific to their control of Ral signaling output rather than other published functions of these proteins. In this capacity Ral functions cell autonomously as a permissive developmental signal. In contrast, we observed Ras, the canonical activator of RalGEF>Ral signaling in cancer, to function as an instructive signal. Furthermore, we unexpectedly identified a function for the close Ras relative, Rap1, consistent with activation of RalGEF>Ral. These studies define functions of RalGEF>Ral, Rap1 and Ras signaling in morphogenetic processes that fashion the nervous system. We have also defined a model for studying how small GTPases partner with downstream effectors. Taken together, this analysis defines novel molecules and relationships in signaling networks that control cell movements during development of the nervous system.
Collapse
|
14
|
Abstract
As multi-cellular organisms evolved from small clusters of cells to complex metazoans, biological tubes became essential for life. Tubes are typically thought of as mainly playing a role in transport, with the hollow space (lumen) acting as a conduit to distribute nutrients and waste, or for gas exchange. However, biological tubes also provide a platform for physiological, mechanical, and structural functions. Indeed, tubulogenesis is often a critical aspect of morphogenesis and organogenesis. C. elegans is made up of tubes that provide structural support and protection (the epidermis), perform the mechanical and enzymatic processes of digestion (the buccal cavity, pharynx, intestine, and rectum), transport fluids for osmoregulation (the excretory system), and execute the functions necessary for reproduction (the germline, spermatheca, uterus and vulva). Here we review our current understanding of the genetic regulation, molecular processes, and physical forces involved in tubulogenesis and morphogenesis of the epidermal, digestive and excretory systems in C. elegans.
Collapse
Affiliation(s)
- Daniel D Shaye
- Department of Physiology and Biophysics, University of Illinois at Chicago-College of Medicine, Chicago, IL, United States.
| | - Martha C Soto
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ, United States.
| |
Collapse
|