scholarly journals Drosophila USP22/nonstop polarizes the actin cytoskeleton during collective border cell migration

2021 ◽  
Vol 220 (7) ◽  
Author(s):  
Hammed Badmos ◽  
Neville Cobbe ◽  
Amy Campbell ◽  
Richard Jackson ◽  
Daimark Bennett

Polarization of the actin cytoskeleton is vital for the collective migration of cells in vivo. During invasive border cell migration in Drosophila, actin polarization is directly controlled by the Hippo signaling complex, which resides at contacts between border cells in the cluster. Here, we identify, in a genetic screen for deubiquitinating enzymes involved in border cell migration, an essential role for nonstop/USP22 in the expression of Hippo pathway components expanded and merlin. Loss of nonstop function consequently leads to a redistribution of F-actin and the polarity determinant Crumbs, loss of polarized actin protrusions, and tumbling of the border cell cluster. Nonstop is a component of the Spt-Ada-Gcn5-acetyltransferase (SAGA) transcriptional coactivator complex, but SAGA’s histone acetyltransferase module, which does not bind to expanded or merlin, is dispensable for migration. Taken together, our results uncover novel roles for SAGA-independent nonstop/USP22 in collective cell migration, which may help guide studies in other systems where USP22 is necessary for cell motility and invasion.

2020 ◽  
Author(s):  
Hammed Badmos ◽  
Neville Cobbe ◽  
Amy Campbell ◽  
Daimark Bennett

Polarisation of the actin cytoskeleton is vital for the collective migration of cells in vivo. During invasive border cell migration in Drosophila, actin polarisation is directly controlled by Hippo pathway components, which reside at contacts between border cells in the cluster. Here we identify, in a genetic screen for deubiquitinating enzymes involved in border cell migration, an essential role for non-stop/USP22 in the expression of Hippo pathway components expanded and merlin; loss of non-stop function consequently leads to a redistribution of F-actin and the polarity determinant Crumbs, loss of polarised actin protrusions and premature tumbling of the border cell cluster. Non-stop is a component of the Spt-Ada-Gcn5-acetyltransferase (SAGA) transcriptional coactivator complex, but SAGA’s histone acetyltransferase module, which does not bind to expanded or merlin, is dispensable for migration. Taken together, our results uncover novel roles for SAGA-independent non-stop/USP22 in Hippo-mediated collective cell migration, which may help guide studies in other systems where USP22 is necessary for cell motility and invasion.


2013 ◽  
Vol 201 (6) ◽  
pp. 875-885 ◽  
Author(s):  
Eliana P. Lucas ◽  
Ichha Khanal ◽  
Pedro Gaspar ◽  
Georgina C. Fletcher ◽  
Cedric Polesello ◽  
...  

Collective migration of Drosophila border cells depends on a dynamic actin cytoskeleton that is highly polarized such that it concentrates around the outer rim of the migrating cluster of cells. How the actin cytoskeleton becomes polarized in these cells to enable collective movement remains unknown. Here we show that the Hippo signaling pathway links determinants of cell polarity to polarization of the actin cytoskeleton in border cells. Upstream Hippo pathway components localize to contacts between border cells inside the cluster and signal through the Hippo and Warts kinases to polarize actin and promote border cell migration. Phosphorylation of the transcriptional coactivator Yorkie (Yki)/YAP by Warts does not mediate the function of this pathway in promoting border cell migration, but rather provides negative feedback to limit the speed of migration. Instead, Warts phosphorylates and inhibits the actin regulator Ena to activate F-actin Capping protein activity on inner membranes and thereby restricts F-actin polymerization mainly to the outer rim of the migrating cluster.


2017 ◽  
Author(s):  
Yasmin Sallak ◽  
Alba Yurani Torres ◽  
Hongyan Yin ◽  
Denise Montell

AbstractThe tyrosine kinase Src is over-expressed in numerous human cancers and is associated with poor prognosis. While Src has been extensively studied, its contributions to collective cell migration in vivo remain incompletely understood. Here we show that Src42A, but not Src64, is required for the specification and migration of the border cells in the Drosophila ovary, a well-developed and genetically tractable in vivo cell migration model. We found active Src42A enriched at border cell/nurse cell interfaces, where E-cadherin is less abundant, and depleted from border cell/border cell and border cell/polar cell junctions where E-cadherin is more stable, whereas total Src42A protein co-localizes with E-cadherin. Over-expression of wild type Src42A mislocalized Src activity and prevented border cell migration. Constitutively active or kinase dead forms of Src42A also impeded border cells. These findings establish border cells as a model for investigating the mechanisms of action of Src in cooperative, collective, cell-on-cell migration in vivo.


2019 ◽  
Author(s):  
Maureen C. Lamb ◽  
Kelsey K. Anliker ◽  
Tina L. Tootle

AbstractFascin is an actin bundling protein that is essential for developmental cell migrations and promotes cancer metastasis. In addition to bundling actin, Fascin has several actin-independent roles. Border cell migration during Drosophila oogenesis provides an excellent model to study Fascin’s various roles during invasive, collective cell migration. Border cell migration requires Fascin. Fascin functions not only within the migrating border cells, but also within the nurse cells, the substrate for this migration. Loss of Fascin results in increased, shorter and mislocalized protrusions during migration. Data supports the model that Fascin promotes the activity of Enabled, an actin elongating factor, to regulate migration. Additionally, loss of Fascin inhibits border cell delamination. These defects are partially due to altered E-cadherin localization in the border cells; this is predicted to be an actin-independent role of Fascin. Overall, Fascin is essential for multiple aspects of this invasive, collective cell migration, and functions in both actin-dependent and -independent manners. These findings have implications beyond Drosophila, as border cell migration has emerged as a model to study mechanisms mediating cancer metastasis.


2016 ◽  
Vol 27 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Wenjuan Xiang ◽  
Dabing Zhang ◽  
Denise J. Montell

Collective cell migration is emerging as a major contributor to normal development and disease. Collective movement of border cells in the Drosophila ovary requires cooperation between two distinct cell types: four to six migratory cells surrounding two immotile cells called polar cells. Polar cells secrete a cytokine, Unpaired (Upd), which activates JAK/STAT signaling in neighboring cells, stimulating their motility. Without Upd, migration fails, causing sterility. Ectopic Upd expression is sufficient to stimulate motility in otherwise immobile cells. Thus regulation of Upd is key. Here we report a limited RNAi screen for nuclear proteins required for border cell migration, which revealed that the gene encoding Tousled-like kinase (Tlk) is required in polar cells for Upd expression without affecting polar cell fate. In the absence of Tlk, fewer border cells are recruited and motility is impaired, similar to inhibition of JAK/STAT signaling. We further show that Tlk in polar cells is required for JAK/STAT activation in border cells. Genetic interactions further confirmed Tlk as a new regulator of Upd/JAK/STAT signaling. These findings shed light on the molecular mechanisms regulating the cooperation of motile and nonmotile cells during collective invasion, a phenomenon that may also drive metastatic cancer.


2021 ◽  
Author(s):  
Maureen C. Lamb ◽  
Chathuri P. Kaluarachchi ◽  
Thiranjeewa I. Lansakara ◽  
Yiling Lan ◽  
Alexei V. Tivanski ◽  
...  

AbstractA key regulator of collective cell migrations, which drive development and cancer metastasis, is substrate stiffness. Increased substrate stiffness promotes migration and is controlled by Myosin. Using Drosophila border cell migration as a model of collective cell migration, we identify, for the first time, that the actin bundling protein Fascin limits Myosin activity in vivo. Loss of Fascin results in: increased activated Myosin on the border cells and their substrate, the nurse cells; decreased border cell Myosin dynamics; and increased nurse cell stiffness as measured by atomic force microscopy. Reducing Myosin restores on-time border cell migration in fascin mutant follicles. Further, Fascin’s actin bundling activity is required to limit Myosin activation. Surprisingly, we find that Fascin regulates Myosin activity in the border cells to control nurse cell stiffness to promote migration. Thus, these data shift the paradigm from a substrate stiffness-centric model of regulating migration, to uncover that collectively migrating cells play a critical role in controlling the mechanical properties of their substrate in order to promote their own migration. This new means of mechanical regulation of migration is likely conserved across contexts and organisms, as Fascin and Myosin are common regulators of cell migration.


2021 ◽  
Author(s):  
Lauren Penfield ◽  
Denise Montell

Cells migrate collectively through confined environments during development and cancer metastasis. While the nucleus, a large and stiff organelle, impedes cell migration between non-deformable pillars in vitro, its function in vivo may vary depending on the microenvironment. Further, it is unknown how nuclei contribute to collective migration in vivo and whether nuclei in different positions within cell collectives experience different forces. Here, we use border cell migration in the fly ovary as an in vivo model to investigate the effects of confined, collective migration on nuclei and the contribution of nuclear lamins to migration. We found severe yet transient nuclear deformations occur, particularly in the leading cell, as border cells squeeze through tiny crevices between germline cells, termed nurse cells. Leading cells extend protrusions between nurse cells, which may pry open space to allow the cluster to advance. Here we report that the leading cell nuclei deformed as they moved into leading protrusions. Then as protrusions widened, the nucleus recovered a more circular shape. These data suggest that lead cell nuclei may help protrusions expand and thereby enlarge the migration path. To test how nuclei might promote or impede border cell migration, we investigated nuclear lamins, proteins that assemble into intermediate filaments and structurally support the nuclear envelope. Depletion of the Drosophila B-type lamin, Lam, from the outer, motile border cells, but not the inner, nonmotile polar cells, impeded border cell migration, whereas perturbations of the A-type lamin, LamC, did not. While wild type border cell clusters typically have one large leading protrusion as they delaminate from the anterior follicular epithelium, clusters depleted of B-type lamin had multiple, short-lived protrusions, resulting in unproductive cluster movement and failure to progress along the migration path. Further, border cell nuclei depleted of B-type lamins were small, formed blebs, and ruptured. Together, these data indicate that B-type lamin is requied for nuclear integrity, which in turn stabilizes the leading protrusion and promotes overall cluster polarization and collective movement through confined spaces.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Maureen C Lamb ◽  
Chathuri P Kaluarachchi ◽  
Thiranjeewa I Lansakara ◽  
Samuel Q Mellentine ◽  
Yiling Lan ◽  
...  

A key regulator of collective cell migrations, which drive development and cancer metastasis, is substrate stiffness. Increased substrate stiffness promotes migration and is controlled by Myosin. Using Drosophila border cell migration as a model of collective cell migration, we identify, for the first time, that the actin bundling protein Fascin limits Myosin activity in vivo. Loss of Fascin results in: increased activated Myosin on the border cells and their substrate, the nurse cells; decreased border cell Myosin dynamics; and increased nurse cell stiffness as measured by atomic force microscopy. Reducing Myosin restores on-time border cell migration in fascin mutant follicles. Further, Fascin’s actin bundling activity is required to limit Myosin activation. Surprisingly, we find that Fascin regulates Myosin activity in the border cells to control nurse cell stiffness to promote migration. Thus, these data shift the paradigm from a substrate stiffness-centric model of regulating migration, to uncover that collectively migrating cells play a critical role in controlling the mechanical properties of their substrate in order to promote their own migration. This understudied means of mechanical regulation of migration is likely conserved across contexts and organisms, as Fascin and Myosin are common regulators of cell migration.


2021 ◽  
Author(s):  
XIAORAN GUO ◽  
Wei Dai ◽  
Denise Montell

Collective cell migration is critical for normal development, wound healing, and in tumor progression and metastasis. Border cells in the Drosophila ovary provide a genetically tractable model to identify molecular mechanisms that drive this important cell behavior. In an unbiased screen for defects in border cell migration in mosaic clones, we identified a mutation in the catsup gene. Catsup, the Drosophila ortholog of Zip7, is a large, multifunctional, transmembrane protein of the endoplasmic reticulum (ER), which has been reported to negatively regulate catecholamine biosynthesis, to regulate Notch signaling, to function as a zinc transporter, and to limit ER stress. Here we report that catsup knockdown caused ER stress in border cells and that ectopic induction of ER stress was sufficient to block migration. Notch and EGFR trafficking were also disrupted. Wild type Catsup rescued the migration defect but point mutations known to disrupt the zinc ion transport of Zip7 did not. We conclude that migrating cells are particularly susceptible to defects in zinc transport and ER homeostasis.


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