scholarly journals Eph signaling controls mitotic spindle orientation and cell proliferation in neuroepithelial cells

2019 ◽  
Vol 218 (4) ◽  
pp. 1200-1217 ◽  
Author(s):  
Maribel Franco ◽  
Ana Carmena
Keyword(s):  
Cell Proliferation ◽  
Cell Fate ◽  
Mitotic Spindle ◽  
Optic Lobe ◽  
Spindle Orientation ◽  
Intercellular Signaling ◽  
Neuroepithelial Cells ◽  
Core Components ◽  
Conserved Core ◽  
Activity Dependent

Mitotic spindle orientation must be tightly regulated during development and adult tissue homeostasis. It determines cell-fate specification and tissue architecture during asymmetric and symmetric cell division, respectively. Here, we uncover a novel role for Ephrin–Eph intercellular signaling in controlling mitotic spindle alignment in Drosophila optic lobe neuroepithelial cells through aPKC activity–dependent myosin II regulation. We show that conserved core components of the mitotic spindle orientation machinery, including Discs Large1, Mud/NuMA, and Canoe/Afadin, mislocalize in dividing Eph mutant neuroepithelial cells and produce spindle alignment defects in these cells when they are down-regulated. In addition, the loss of Eph leads to a Rho signaling–dependent activation of the PI3K–Akt1 pathway, enhancing cell proliferation within this neuroepithelium. Hence, Eph signaling is a novel extrinsic mechanism that regulates both spindle orientation and cell proliferation in the Drosophila optic lobe neuroepithelium. Similar mechanisms could operate in other Drosophila and vertebrate epithelia.

scholarly journals Mitotic spindle (DIS)orientation and DISease: Cause or consequence?

2012 ◽  
Vol 199 (7) ◽  
pp. 1025-1035 ◽  
Author(s):  
Anna Noatynska ◽  
Monica Gotta ◽  
Patrick Meraldi
Keyword(s):  
Cell Proliferation ◽  
Cell Fate ◽  
Mitotic Spindle ◽  
Brain Diseases ◽  
Spindle Orientation ◽  
Cell Fate Determination ◽  
Cellular Functions ◽  
Tissue Organization ◽  
Asymmetric Divisions ◽  
Correct Alignment

Correct alignment of the mitotic spindle during cell division is crucial for cell fate determination, tissue organization, and development. Mutations causing brain diseases and cancer in humans and mice have been associated with spindle orientation defects. These defects are thought to lead to an imbalance between symmetric and asymmetric divisions, causing reduced or excessive cell proliferation. However, most of these disease-linked genes encode proteins that carry out multiple cellular functions. Here, we discuss whether spindle orientation defects are the direct cause for these diseases, or just a correlative side effect.

scholarly journals NuMA-microtubule interactions are critical for spindle orientation and the morphogenesis of diverse epidermal structures

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Lindsey Seldin ◽  
Andrew Muroyama ◽  
Terry Lechler
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Cell Types ◽  
Epidermal Differentiation ◽  
Spindle Orientation ◽  
Direct Function ◽  
Spindle Positioning ◽  
Adult Mice ◽  
Neonatal Lethality ◽  
The Matrix

Mitotic spindle orientation is used to generate cell fate diversity and drive proper tissue morphogenesis. A complex of NuMA and dynein/dynactin is required for robust spindle orientation in a number of cell types. Previous research proposed that cortical dynein/dynactin was sufficient to generate forces on astral microtubules (MTs) to orient the spindle, with NuMA acting as a passive tether. In this study, we demonstrate that dynein/dynactin is insufficient for spindle orientation establishment in keratinocytes and that NuMA’s MT-binding domain, which targets MT tips, is also required. Loss of NuMA-MT interactions in skin caused defects in spindle orientation and epidermal differentiation, leading to neonatal lethality. In addition, we show that NuMA-MT interactions are also required in adult mice for hair follicle morphogenesis and spindle orientation within the transit-amplifying cells of the matrix. Loss of spindle orientation in matrix cells results in defective differentiation of matrix-derived lineages. Our results reveal an additional and direct function of NuMA during mitotic spindle positioning, as well as a reiterative use of spindle orientation in the skin to build diverse structures.

scholarly journals A lateral belt of cortical LGN and NuMA guides mitotic spindle movements and planar division in neuroepithelial cells

2011 ◽  
Vol 193 (1) ◽  
pp. 141-154 ◽  
Author(s):  
Elise Peyre ◽  
Florence Jaouen ◽  
Mehdi Saadaoui ◽  
Laurence Haren ◽  
Andreas Merdes ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Three Dimensional ◽  
Active Phase ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Neuroepithelial Cells ◽  
Subsequent Phase ◽  
Planar Orientation ◽  
Lateral Cell ◽  
Apical Localization

To maintain tissue architecture, epithelial cells divide in a planar fashion, perpendicular to their main polarity axis. As the centrosome resumes an apical localization in interphase, planar spindle orientation is reset at each cell cycle. We used three-dimensional live imaging of GFP-labeled centrosomes to investigate the dynamics of spindle orientation in chick neuroepithelial cells. The mitotic spindle displays stereotypic movements during metaphase, with an active phase of planar orientation and a subsequent phase of planar maintenance before anaphase. We describe the localization of the NuMA and LGN proteins in a belt at the lateral cell cortex during spindle orientation. Finally, we show that the complex formed of LGN, NuMA, and of cortically located Gαi subunits is necessary for spindle movements and regulates the dynamics of spindle orientation. The restricted localization of LGN and NuMA in the lateral belt is instructive for the planar alignment of the mitotic spindle, and required for its planar maintenance.

scholarly journals Membrane Targeting and Asymmetric Localization of Drosophila Partner of Inscuteable Are Discrete Steps Controlled by Distinct Regions of the Protein

2002 ◽  
Vol 22 (12) ◽  
pp. 4230-4240 ◽  
Author(s):  
Fengwei Yu ◽  
Chin Tong Ong ◽  
William Chia ◽  
Xiaohang Yang
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Protein Localization ◽  
Asymmetric Division ◽  
Terminal Region ◽  
Spindle Orientation ◽  
Functional Domain ◽  
Fate Determinants ◽  
Cell Fate Determinants ◽  
Apical Localization

ABSTRACT Asymmetric division of neural progenitors is a key mechanism by which neuronal diversity in the Drosophila central nervous system is generated. The distinct fates of the daughter cells derived from these divisions are achieved through preferential segregation of the cell fate determinants Prospero and Numb to one of the two daughters. This is achieved by coordinating apical and basal mitotic spindle orientation with the basal cortical localization of the cell fate determinants during mitosis. A complex of apically localized proteins, including Inscuteable (Insc), Partner of Inscuteable (Pins), Bazooka (Baz), DmPar-6, DaPKC, and Gαi, is required to mediate and coordinate basal protein localization with mitotic spindle orientation. Pins, a molecule which directly interacts with Insc, is a key component required for the integrity of this complex; in the absence of Pins, other components become mislocalized or destabilized, and basal protein localization and mitotic spindle orientation are defective. Here we define the functional domains of Pins. We show that the C-terminal region containing the Gαi binding GoLoco motifs is necessary and sufficient for targeting to the neuroblast cortex, which appears to be a prerequisite for apical localization of Pins. The N-terminal tetratricopeptide repeat-containing region of Pins is required for two processes; TPR repeats 1 to 3 plus the C-terminal region are required for apical localization but are insufficient to recruit Insc to the apical cortex, whereas TPR repeats 1 to 7 plus C-terminal Pins can perform both functions. Hence, the abilities of Pins to cortically localize, to apically localize, and to restore Insc apical localization are all separable, and all three capabilities are necessary to mediate asymmetric division. Moreover, the need for N-terminal Pins can be obviated by fusing a minimal Insc functional domain with the C-terminal region of Pins; this chimeric molecule is apically localized and can fulfill the functions of both Insc and Pins.

scholarly journals Junctional tumor suppressors interact with 14-3-3 proteins to control planar spindle alignment

2019 ◽  
Vol 218 (6) ◽  
pp. 1824-1838 ◽  
Author(s):  
Yu-ichiro Nakajima ◽  
Zachary T. Lee ◽  
Sean A. McKinney ◽  
Selene K. Swanson ◽  
Laurence Florens ◽  
...  
Keyword(s):  
Cell Fate ◽  
Tumor Suppressors ◽  
Mitotic Spindle ◽  
Wing Disc ◽  
Spindle Orientation ◽  
Epithelial Proliferation ◽  
Tissue Architecture ◽  
Drosophila Wing ◽  
Discs Large

Proper orientation of the mitotic spindle is essential for cell fate determination, tissue morphogenesis, and homeostasis. During epithelial proliferation, planar spindle alignment ensures the maintenance of polarized tissue architecture, and aberrant spindle orientation can disrupt epithelial integrity. Nevertheless, in vivo mechanisms that restrict the mitotic spindle to the plane of the epithelium remain poorly understood. Here we show that the junction-localized tumor suppressors Scribbled (Scrib) and Discs large (Dlg) control planar spindle orientation via Mud and 14-3-3 proteins in the Drosophila wing disc epithelium. During mitosis, Scrib is required for the junctional localization of Dlg, and both affect mitotic spindle movements. Using coimmunoprecipitation and mass spectrometry, we identify 14-3-3 proteins as Dlg-interacting partners and further report that loss of 14-3-3s causes both abnormal spindle orientation and disruption of epithelial architecture as a consequence of basal cell delamination and apoptosis. Combined, these biochemical and genetic analyses indicate that 14-3-3s function together with Scrib, Dlg, and Mud during planar cell division.

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