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Messer CL, Burghardt E, McDonald JA. A deficiency screen of the X chromosome for Rap1 GTPase dominant interacting genes in Drosophila border cell migration. G3 (BETHESDA, MD.) 2025; 15:jkaf040. [PMID: 39993182 PMCID: PMC12060239 DOI: 10.1093/g3journal/jkaf040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2024] [Revised: 02/17/2025] [Accepted: 02/18/2025] [Indexed: 02/26/2025]
Abstract
Collective cell migration is critical to embryonic development, wound healing, and the immune response, but also drives tumor dissemination. Understanding how cell collectives coordinate migration in vivo has been a challenge, with potential therapeutic benefits that range from addressing developmental defects to designing targeted cancer treatments. The small GTPase Rap1 has emerged as a regulator of both embryogenesis and cancer cell migration. How active Rap1 coordinates downstream signaling functions required for coordinated collective migration is poorly understood. Drosophila border cells undergo a stereotyped and genetically tractable in vivo migration within the developing egg chamber of the ovary. This group of 6-8 cells migrates through a densely packed tissue microenvironment and serves as an excellent model for collective cell migration during development and disease. Rap1, like all small GTPases, has distinct activity state switches that link extracellular signals to organized cell behaviors. Proper regulation of Rap1 activity is essential for successful border cell migration yet the signaling partners and other downstream effectors are poorly characterized. Using the known requirement for Rap1 in border cell migration, we conducted a dominant suppressor screen for genes whose heterozygous loss modifies the migration defects observed upon constitutively active Rap1V12 expression. Here, we identified 7 genomic regions on the X chromosome that interact with Rap1V12. We mapped three genomic regions to single Rap1-interacting genes, frizzled 4, Ubiquitin-specific protease 16/45, and strawberry notch. Thus, this unbiased screening approach identified multiple new candidate regulators of Rap1 activity with roles in collective border cell migration.
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Affiliation(s)
- C Luke Messer
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
- Department of Natural Sciences, The University of Virginia's College at Wise, Wise, VA 24293, USA
| | - Emily Burghardt
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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Patel B, Patel J, Cho JH, Manne S, Bonala S, Henske E, Roegiers F, Markiewski M, Karbowniczek M. Exosomes mediate the acquisition of the disease phenotypes by cells with normal genome in tuberous sclerosis complex. Oncogene 2015; 35:3027-36. [DOI: 10.1038/onc.2015.358] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 07/31/2015] [Accepted: 08/24/2015] [Indexed: 01/14/2023]
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Rao SG, Janiszewski MM, Duca E, Nelson B, Abhinav K, Panagakou I, Vass S, Heck MMS. Invadolysin acts genetically via the SAGA complex to modulate chromosome structure. Nucleic Acids Res 2015; 43:3546-62. [PMID: 25779050 PMCID: PMC4402531 DOI: 10.1093/nar/gkv211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 02/28/2015] [Indexed: 11/24/2022] Open
Abstract
Identification of components essential to chromosome structure and behaviour remains a vibrant area of study. We have previously shown that invadolysin is essential in Drosophila, with roles in cell division and cell migration. Mitotic chromosomes are hypercondensed in length, but display an aberrant fuzzy appearance. We additionally demonstrated that in human cells, invadolysin is localized on the surface of lipid droplets, organelles that store not only triglycerides and sterols but also free histones H2A, H2Av and H2B. Is there a link between the storage of histones in lipid droplets and the aberrantly structured chromosomes of invadolysin mutants? We have identified a genetic interaction between invadolysin and nonstop, the de-ubiquitinating protease component of the SAGA (Spt-Ada-Gcn5-acetyltransferase) chromatin-remodelling complex. invadolysin and nonstop mutants exhibit phenotypic similarities in terms of chromosome structure in both diploid and polyploid cells. Furthermore, IX-141/not1 transheterozygous animals accumulate mono-ubiquitinated histone H2B (ubH2B) and histone H3 tri-methylated at lysine 4 (H3K4me3). Whole mount immunostaining of IX-141/not1 transheterozygous salivary glands revealed that ubH2B accumulates surprisingly in the cytoplasm, rather than the nucleus. Over-expression of the Bre1 ubiquitin ligase phenocopies the effects of mutating either the invadolysin or nonstop genes. Intriguingly, nonstop and mutants of other SAGA subunits (gcn5, ada2b and sgf11) all suppress an invadolysin-induced rough eye phenotype. We conclude that the abnormal chromosome phenotype of invadolysin mutants is likely the result of disrupting the histone modification cycle, as accumulation of ubH2B and H3K4me3 is observed. We further suggest that the mislocalization of ubH2B to the cytoplasm has additional consequences on downstream components essential for chromosome behaviour. We therefore propose that invadolysin plays a crucial role in chromosome organization via its interaction with the SAGA complex.
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Affiliation(s)
- Shubha Gururaja Rao
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Michal M Janiszewski
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Edward Duca
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Bryce Nelson
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Kanishk Abhinav
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Ioanna Panagakou
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Sharron Vass
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Margarete M S Heck
- University of Edinburgh, Queen's Medical Research Institute, University/BHF Centre for Cardiovascular Science, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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Hall S, Bone C, Oshima K, Zhang L, McGraw M, Lucas B, Fehon RG, Ward RE. Macroglobulin complement-related encodes a protein required for septate junction organization and paracellular barrier function in Drosophila. Development 2014; 141:889-98. [PMID: 24496625 DOI: 10.1242/dev.102152] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Polarized epithelia play crucial roles as barriers to the outside environment and enable the formation of specialized compartments for organs to carry out essential functions. Barrier functions are mediated by cellular junctions that line the lateral plasma membrane between cells, principally tight junctions in vertebrates and septate junctions (SJs) in invertebrates. Over the last two decades, more than 20 genes have been identified that function in SJ biogenesis in Drosophila, including those that encode core structural components of the junction such as Neurexin IV, Coracle and several claudins, as well as proteins that facilitate the trafficking of SJ proteins during their assembly. Here we demonstrate that Macroglobulin complement-related (Mcr), a gene previously implicated in innate immunity, plays an essential role during embryonic development in SJ organization and function. We show that Mcr colocalizes with other SJ proteins in mature ectodermally derived epithelial cells, that it shows interdependence with other SJ proteins for SJ localization, and that Mcr mutant epithelia fail to form an effective paracellular barrier. Tissue-specific RNA interference further demonstrates that Mcr is required cell-autonomously for SJ organization. Finally, we show a unique interdependence between Mcr and Nrg for SJ localization that provides new insights into the organization of the SJ. Together, these studies demonstrate that Mcr is a core component of epithelial SJs and also highlight an interesting relationship between innate immunity and epithelial barrier functions.
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Affiliation(s)
- Sonia Hall
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
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Manning AJ, Peters KA, Peifer M, Rogers SL. Regulation of epithelial morphogenesis by the G protein-coupled receptor mist and its ligand fog. Sci Signal 2013; 6:ra98. [PMID: 24222713 DOI: 10.1126/scisignal.2004427] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Epithelial morphogenesis is essential for shaping organs and tissues and for establishment of the three embryonic germ layers during gastrulation. Studies of gastrulation in Drosophila have provided insight into how epithelial morphogenesis is governed by developmental patterning mechanisms. We developed an assay to recapitulate morphogenetic shape changes in individual cultured cells and used RNA interference-based screening to identify Mist, a Drosophila G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR) that transduces signals from the secreted ligand Folded gastrulation (Fog) in cultured cells. Mist functioned in Fog-dependent embryonic morphogenesis, and the transcription factor Snail regulated expression of mist in zygotes. Our data revealed how a cell fate transcriptional program acts through a ligand-GPCR pair to stimulate epithelial morphogenetic shape changes.
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Affiliation(s)
- Alyssa J Manning
- 1Department of Biology, University of North Carolina at Chapel Hill, CB# 3280, Fordham Hall, South Road, Chapel Hill, NC 27599-3280, USA
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Neuman NA, Henske EP. Non-canonical functions of the tuberous sclerosis complex-Rheb signalling axis. EMBO Mol Med 2011; 3:189-200. [PMID: 21412983 PMCID: PMC3377068 DOI: 10.1002/emmm.201100131] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 02/11/2011] [Accepted: 02/16/2011] [Indexed: 01/10/2023] Open
Abstract
The protein products of the tuberous sclerosis complex (TSC) genes, TSC1 and TSC2, form a complex, which inhibits the small G-protein, Ras homolog enriched in brain (Rheb). The vast majority of research regarding these proteins has focused on mammalian Target of Rapamycin (mTOR), a target of Rheb. Here, we propose that there are clinically relevant functions and targets of TSC1, TSC2 and Rheb, which are independent of mTOR. We present evidence that such non-canonical functions of the TSC-Rheb signalling network exist, propose a standard of evidence for these non-canonical functions, and discuss their potential clinical and therapeutic implications for patients with TSC and lymphangioleiomyomatosis (LAM).
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Affiliation(s)
- Nicole A Neuman
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Identification of novel Ras-cooperating oncogenes in Drosophila melanogaster: a RhoGEF/Rho-family/JNK pathway is a central driver of tumorigenesis. Genetics 2011; 188:105-25. [PMID: 21368274 DOI: 10.1534/genetics.111.127910] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have shown previously that mutations in the apico-basal cell polarity regulators cooperate with oncogenic Ras (Ras(ACT)) to promote tumorigenesis in Drosophila melanogaster and mammalian cells. To identify novel genes that cooperate with Ras(ACT) in tumorigenesis, we carried out a genome-wide screen for genes that when overexpressed throughout the developing Drosophila eye enhance Ras(ACT)-driven hyperplasia. Ras(ACT)-cooperating genes identified were Rac1 Rho1, RhoGEF2, pbl, rib, and east, which encode cell morphology regulators. In a clonal setting, which reveals genes conferring a competitive advantage over wild-type cells, only Rac1, an activated allele of Rho1 (Rho1(ACT)), RhoGEF2, and pbl cooperated with Ras(ACT), resulting in reduced differentiation and large invasive tumors. Expression of RhoGEF2 or Rac1 with Ras(ACT) upregulated Jun kinase (JNK) activity, and JNK upregulation was essential for cooperation. However, in the whole-tissue system, upregulation of JNK alone was not sufficient for cooperation with Ras(ACT), while in the clonal setting, JNK upregulation was sufficient for Ras(ACT)-mediated tumorigenesis. JNK upregulation was also sufficient to confer invasive growth of Ras(V12)-expressing mammalian MCF10A breast epithelial cells. Consistent with this, HER2(+) human breast cancers (where human epidermal growth factor 2 is overexpressed and Ras signaling upregulated) show a significant correlation with a signature representing JNK pathway activation. Moreover, our genetic analysis in Drosophila revealed that Rho1 and Rac are important for the cooperation of RhoGEF2 or Pbl overexpression and of mutants in polarity regulators, Dlg and aPKC, with Ras(ACT) in the whole-tissue context. Collectively our analysis reveals the importance of the RhoGEF/Rho-family/JNK pathway in cooperative tumorigenesis with Ras(ACT).
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Vlachos S, Harden N. Genetic evidence for antagonism between Pak protein kinase and Rho1 small GTPase signaling in regulation of the actin cytoskeleton during Drosophila oogenesis. Genetics 2011; 187:501-12. [PMID: 21098722 PMCID: PMC3030492 DOI: 10.1534/genetics.110.120998] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/18/2010] [Indexed: 12/15/2022] Open
Abstract
During Drosophila oogenesis, basally localized F-actin bundles in the follicle cells covering the egg chamber drive its elongation along the anterior-posterior axis. The basal F-actin of the follicle cell is an attractive system for the genetic analysis of the regulation of the actin cytoskeleton, and results obtained in this system are likely to be broadly applicable in understanding tissue remodeling. Mutations in a number of genes, including that encoding the p21-activated kinase Pak, have been shown to disrupt organization of the basal F-actin and in turn affect egg chamber elongation. pak mutant egg chambers have disorganized F-actin distribution and remain spherical due to a failure to elongate. In a genetic screen to identify modifiers of the pak rounded egg chamber phenotype several second chromosome deficiencies were identified as suppressors. One suppressing deficiency removes the rho1 locus, and we determined using several rho1 alleles that removal of a single copy of rho1 can suppress the pak phenotype. Reduction of any component of the Rho1-activated actomyosin contractility pathway suppresses pak oogenesis defects, suggesting that Pak counteracts Rho1 signaling. There is ectopic myosin light chain phosphorylation in pak mutant follicle cell clones in elongating egg chambers, probably due at least in part to mislocalization of RhoGEF2, an activator of the Rho1 pathway. In early egg chambers, pak mutant follicle cells have reduced levels of myosin phosphorylation and we conclude that Pak both promotes and restricts myosin light chain phosphorylation in a temporally distinct manner during oogenesis.
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Affiliation(s)
| | - Nicholas Harden
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
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