scholarly journals Crumbs interacts with moesin and βHeavy-spectrin in the apical membrane skeleton of Drosophila

2002 ◽  
Vol 158 (5) ◽  
pp. 941-951 ◽  
Author(s):  
Emmanuelle Médina ◽  
Janice Williams ◽  
Elizabeth Klipfell ◽  
Daniela Zarnescu ◽  
Graham Thomas ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Apical Membrane ◽  
Transmembrane Protein ◽  
Membrane Skeleton ◽  
Cell Polarization ◽  
Epithelial Morphogenesis ◽  
Protein Network ◽  
Ferm Domain ◽  
Junctional Region ◽  
Domain Protein

The apical transmembrane protein Crumbs is necessary for both cell polarization and the assembly of the zonula adherens (ZA) in Drosophila epithelia. The apical spectrin-based membrane skeleton (SBMS) is a protein network that is essential for epithelial morphogenesis and ZA integrity, and exhibits close colocalization with Crumbs and the ZA in fly epithelia. These observations suggest that Crumbs may stabilize the ZA by recruiting the SBMS to the junctional region. Consistent with this hypothesis, we report that Crumbs is necessary for the organization of the apical SBMS in embryos and Schneider 2 cells, whereas the localization of Crumbs is not affected in karst mutants that eliminate the apical SBMS. Our data indicate that it is specifically the 4.1 protein/ezrin/radixin/moesin (FERM) domain binding consensus, and in particular, an arginine at position 7 in the cytoplasmic tail of Crumbs that is essential to efficiently recruit both the apical SBMS and the FERM domain protein, DMoesin. Crumbs, Discs lost, βHeavy-spectrin, and DMoesin are all coimmunoprecipitated from embryos, confirming the existence of a multimolecular complex. We propose that Crumbs stabilizes the apical SBMS via DMoesin and actin, leading to reinforcement of the ZA and effectively coupling epithelial morphogenesis and cell polarity.

scholarly journals Girdin is a component of the lateral polarity protein network restricting cell dissemination

2019 ◽  
Author(s):  
Cornélia Biehler ◽  
Li-Ting Wang ◽  
Myriam Sévigny ◽  
Alexandra Jetté ◽  
Clémence Gamblin ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Polarity ◽  
Cancer Progression ◽  
Cell Polarization ◽  
Protein Network ◽  
Poor Overall Survival ◽  
Lung Cancers ◽  
Epithelial Cancers ◽  
Human Ortholog ◽  
Cell Dissemination

AbstractEpithelial cell polarity defects support cancer progression. It is thus crucial to decipher the functional interactions within the polarity protein network. Here we show that Drosophila Girdin and its human ortholog (GIRDIN) sustain the function of crucial lateral polarity proteins by inhibiting the apical kinase aPKC. Loss of GIRDIN expression is also associated with overgrowth of disorganized cell cysts. Moreover, we observed cell dissemination from GIRDIN knockdown cysts and tumorspheres, thereby showing that GIRDIN supports the cohesion of multicellular epithelial structures. Consistent with these observations, alteration of GIRDIN expression is associated with a poor overall survival in subtypes of breast and lung cancers. Overall, we discovered a core mechanism contributing to epithelial cell polarization from flies to humans. Our data also indicate that GIRDIN has the potential to impair the progression of epithelial cancers by preserving cell polarity and restricting cell dissemination.

scholarly journals The WD40 protein Morg1 facilitates Par6–aPKC binding to Crb3 for apical identity in epithelial cells

2013 ◽  
Vol 200 (5) ◽  
pp. 635-650 ◽  
Author(s):  
Junya Hayase ◽  
Sachiko Kamakura ◽  
Yuko Iwakiri ◽  
Yoshihiro Yamaguchi ◽  
Tomoko Izaki ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epithelial Cells ◽  
Tight Junction ◽  
Apical Membrane ◽  
Transmembrane Protein ◽  
Cyst Formation ◽  
Cell Polarization ◽  
Small Gtpase ◽  
Apical Surface ◽  
And Function

Formation of apico-basal polarity in epithelial cells is crucial for both morphogenesis (e.g., cyst formation) and function (e.g., tight junction development). Atypical protein kinase C (aPKC), complexed with Par6, is considered to translocate to the apical membrane and function in epithelial cell polarization. However, the mechanism for translocation of the Par6–aPKC complex has remained largely unknown. Here, we show that the WD40 protein Morg1 (mitogen-activated protein kinase organizer 1) directly binds to Par6 and thus facilitates apical targeting of Par6–aPKC in Madin-Darby canine kidney epithelial cells. Morg1 also interacts with the apical transmembrane protein Crumbs3 to promote Par6–aPKC binding to Crumbs3, which is reinforced with the apically localized small GTPase Cdc42. Depletion of Morg1 disrupted both tight junction development in monolayer culture and cyst formation in three-dimensional culture; apico-basal polarity was notably restored by forced targeting of aPKC to the apical surface. Thus, Par6–aPKC recruitment to the premature apical membrane appears to be required for definition of apical identity of epithelial cells.

scholarly journals Dynamic rearrangement of the spectrin membrane skeleton during the generation of epithelial polarity in Drosophila

1999 ◽  
Vol 112 (17) ◽  
pp. 2843-2852 ◽  
Author(s):  
G.H. Thomas ◽  
J.A. Williams
Keyword(s):  
Cell Polarity ◽  
Cell Biology ◽  
Apical Membrane ◽  
Fundamental Problem ◽  
Basolateral Membrane ◽  
Membrane Skeleton ◽  
Common Mechanism ◽  
Primary Role ◽  
Epithelial Polarity ◽  
Membrane Domains

The origin of epithelial cell polarity during development is a fundamental problem in cell biology. Central to this process is the establishment of asymmetric membrane domains that will ultimately form the apical and basolateral surfaces. The spectrin-based membrane skeleton has long been thought to participate in the generation of this asymmetry. Drosophila melanogaster contains two known (beta)-spectrin isoforms: a conventional (beta)-spectrin chain, and the novel isoform (beta)(Heavy)-spectrin. These two proteins are restricted to the basolateral and apical membrane domains, respectively. To assay for the emergence of membrane asymmetry, we have characterized the distribution of these two (beta)-spectrins during the formation of the primary epithelium in the fly embryo. Our results show that the syncytial embryo contains a maternally established apical membrane skeleton containing (beta)(Heavy)-spectrin into which the basolateral (beta)-spectrin membrane skeleton is added. We have called this process basolateral interpolation. Although basolateral membrane skeleton addition begins during cellularization, it does not become fully established until the formation of a mature zonula adherens at mid to late gastrulation. The behavior of (beta)-spectrin is consistent with a primary role in establishing and/or maintaining the basolateral domain while the behavior of (beta)(Heavy)-spectrin suggests that its primary role is associated with a specialized DE-cadherin complex associated with the furrow canals and with the maturation of the zonula adherens. Thus, the apical spectrin membrane skeleton appears to play a distinct rather than analogous role to the basolateral spectrin membrane skeleton, during the emergence of cell polarity. We find that there are several parallels between our observations and previous studies on the establishment of primary epithelial polarity in vertebrates, suggesting that basolateral interpolation of the membrane skeleton may be a common mechanism in many organisms.

scholarly journals The Transforming Rho Family GTPase Wrch-1 Disrupts Epithelial Cell Tight Junctions and Epithelial Morphogenesis

2008 ◽  
Vol 29 (4) ◽  
pp. 1035-1049 ◽  
Author(s):  
Donita C. Brady ◽  
Jamie K. Alan ◽  
James P. Madigan ◽  
Alan S. Fanning ◽  
Adrienne D. Cox
Keyword(s):  
Epithelial Cell ◽  
Cell Polarity ◽  
Rho Gtpase ◽  
Mdck Cells ◽  
3D Culture ◽  
Cell Polarization ◽  
Epithelial Morphogenesis ◽  
Detectable Effect ◽  
Dependent Manner ◽  
Actin Organization

ABSTRACT Wrch-1, an atypical and transforming Rho GTPase, regulates cellular activities including proliferation and actin organization, but its functions and effectors remain poorly characterized. We show here that Wrch-1 distributes along the apical and basolateral membranes in MDCK cells and binds the cell polarity protein Par6 in a GTP-dependent manner. Activated Wrch-1 negatively regulates the kinetics of tight junction (TJ) assembly during epithelial cell polarization but has no detectable effect on overall cell polarity in confluent monolayers. It also causes a dramatic cytoskeletal reorganization and multilayering in cells grown in two-dimensional culture and disrupts cystogenesis of cells grown in three-dimensional (3D) culture. Similarly, short hairpin RNA-mediated knockdown of Wrch-1 perturbs cystogenesis in 3D culture, suggesting that tight regulation of Wrch-1 activity is necessary for normal epithelial morphogenesis. A weakly transforming effector domain mutant of activated Wrch-1 that inhibits Par6 binding abrogates the ability of Wrch-1 to disrupt TJ formation, actin organization, and epithelial morphogenesis. We hypothesize that Wrch-1-induced morphological and growth transformation may occur in part through Par6-mediated disruption of TJs and actin organization.

Cell polarity and tissue patterning in plants

Development ◽  
1991 ◽  
Vol 113 (Supplement_1) ◽  
pp. 83-93 ◽  
Author(s):  
Tsvi Sachs
Keyword(s):  
Cell Polarity ◽  
Cell Shape ◽  
Auxin Transport ◽  
Developmental Stages ◽  
Important Determinant ◽  
Genetic System ◽  
Cell Patterning ◽  
Cell Polarization ◽  
Sources And Sinks ◽  
Tissue Patterning

Cell polarization is the specialization of developmental events along one orientation or one direction. Such polarization must be an early, essential stage of tissue patterning. The specification of orientation could not occur only at the level of the genetic system and it must express a coordination of events in many cells. There is a positive feedback relation between cell polarization and the transport of the known hormone auxin: polarity determines oriented auxin transport while transport itself induces both new and continued polarization. Since cell polarization increases gradually, this feedback leads to the canalization of transport – and of the associated cell differentiation – along defined strands of specialized cells. Recent work has shown that the same canalized flow can also be an important determinant of cell shape. In primordial, embryonic regions cell growth is oriented along the flow of auxin from the shoot towards the root. In later developmental stages the cells respond to the same flow by growing in girth, presumably adjusting the capacity of the tissues to the flow of signals. Finally, disrupted flow near wounds results in the development of relatively unorganized callus. Continued callus development appears to require the participation of the cells, as sources and sinks of auxin and other signals. The overall picture to emerge suggests that cell patterning can result from competition between cells acting as preferred channels, sources and sinks for developmental signals.

scholarly journals Structural insights into the aPKC regulatory switch mechanism of the human cell polarity protein lethal giant larvae 2

2019 ◽  
Vol 116 (22) ◽  
pp. 10804-10812 ◽  
Author(s):  
Lior Almagor ◽  
Ivan S. Ufimtsev ◽  
Aruna Ayer ◽  
Jingzhi Li ◽  
William I. Weis
Keyword(s):  
Cell Polarity ◽  
Apical Membrane ◽  
Kinase C ◽  
Lethal Giant Larvae ◽  
Direct Binding ◽  
Switch Mechanism ◽  
Membrane Phosphorylation ◽  
Metazoan Cell ◽  
Structural Insights

Metazoan cell polarity is controlled by a set of highly conserved proteins. Lethal giant larvae (Lgl) functions in apical-basal polarity through phosphorylation-dependent interactions with several other proteins as well as the plasma membrane. Phosphorylation of Lgl by atypical protein kinase C (aPKC), a component of the partitioning-defective (Par) complex in epithelial cells, excludes Lgl from the apical membrane, a crucial step in the establishment of epithelial cell polarity. We present the crystal structures of human Lgl2 in both its unphosphorylated and aPKC-phosphorylated states. Lgl2 adopts a double β-propeller structure that is unchanged by aPKC phosphorylation of an unstructured loop in its second β-propeller, ruling out models of phosphorylation-dependent conformational change. We demonstrate that phosphorylation controls the direct binding of purified Lgl2 to negative phospholipids in vitro. We also show that a coil–helix transition of this region that is promoted by phosphatidylinositol 4,5-bisphosphate (PIP2) is also phosphorylation-dependent, implying a highly effective phosphorylative switch for membrane association.

scholarly journals Morphogenesis of the mouse node depends on the FERM domain protein Epb4.1l5

2008 ◽  
Vol 319 (2) ◽  
pp. 503
Author(s):  
Jeffrey D. Lee ◽  
Kathryn V. Anderson
Keyword(s):  
Ferm Domain ◽  
Domain Protein

Na+-sugar cotransport system as a polarization marker during organization of epithelial membrane

1988 ◽  
Vol 255 (6) ◽  
pp. C745-C753 ◽  
Author(s):  
C. Lasheras ◽  
J. A. Scott ◽  
C. A. Rabito
Keyword(s):  
Electrical Resistance ◽  
Apical Membrane ◽  
Sugar Transport ◽  
Cell Polarization ◽  
Transepithelial Electrical Resistance ◽  
Apical Surface ◽  
Binding Studies ◽  
Occluding Junctions ◽  
Basolateral Side ◽  
Epithelial Membranes

The present study analyzed the changes in Na+-dependent sugar transport and transepithelial electrical resistance as LLC-PK1 cells reorganize into epithelial membranes. Sugar influx increased to reach a maximum 9 h after plating. The increase in the transepithelial electrical resistance, however, showed a significant delay, reaching steady state 15 h after plating. No changes in the electrochemical Na+ gradient were observed during the reorganization of the epithelial membranes. Kinetic analysis and [3H]phlorizin-binding studies showed that the increase in sugar influx resulted from an increase in the number of carriers. Unidirectional sugar influx measurements indicated that the sugar transporters were primarily located at the apical surface of the epithelial cells. These observations are consistent with the hypothesis that the sorting of native proteins occurs intracellularly before their insertion in the apical membrane, or as an alternative that they are randomly inserted, but then immediately sorted such as any carrier could be detected in the basolateral side during the reorganization process. In addition, the results suggest that the functional development of the apical membrane may occur before the complete sealing of the intercellular space during the development of the occluding junctions. Furthermore, development of the sugar transport system and occluding junctions was inhibited by cycloheximide and puromycin but not by actinomycin D, suggesting that the expression of epithelial cell polarization is probably a posttranslational event in the protein synthesis.

scholarly journals LGN regulates mitotic spindle orientation during epithelial morphogenesis

2010 ◽  
Vol 189 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Zhen Zheng ◽  
Huabin Zhu ◽  
Qingwen Wan ◽  
Jing Liu ◽  
Zhuoni Xiao ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Mdck Cells ◽  
Apical Cell ◽  
Cell Polarization ◽  
Epithelial Morphogenesis ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Dividing Cells ◽  
Cortical Localization ◽  
Lateral Cell

Coordinated cell polarization and mitotic spindle orientation are thought to be important for epithelial morphogenesis. Whether spindle orientation is indeed linked to epithelial morphogenesis and how it is controlled at the molecular level is still unknown. Here, we show that the NuMA- and Gα-binding protein LGN is required for directing spindle orientation during cystogenesis of MDCK cells. LGN localizes to the lateral cell cortex, and is excluded from the apical cell cortex of dividing cells. Depleting LGN, preventing its cortical localization, or disrupting its interaction with endogenous NuMA or Gα proteins all lead to spindle misorientation and abnormal cystogenesis. Moreover, artificial mistargeting of endogenous LGN to the apical membrane results in a near 90° rotation of the spindle axis and profound cystogenesis defects that are dependent on cell division. The normal apical exclusion of LGN during mitosis appears to be mediated by atypical PKC. Thus, cell polarization–mediated spatial restriction of spindle orientation determinants is critical for epithelial morphogenesis.

scholarly journals Actin and microtubules drive differential aspects of planar cell polarity in multiciliated cells

2011 ◽  
Vol 195 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Michael E. Werner ◽  
Peter Hwang ◽  
Fawn Huisman ◽  
Peter Taborek ◽  
Clare C. Yu ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Planar Cell Polarity ◽  
Cell Polarization ◽  
Actin Dynamics ◽  
Cellular Organization ◽  
Cytoplasmic Microtubule ◽  
Local Coordination ◽  
Multiciliated Cells ◽  
Global Coordination ◽  
Microtubule Networks

Planar cell polarization represents the ability of cells to orient within the plane of a tissue orthogonal to the apical basal axis. The proper polarized function of multiciliated cells requires the coordination of cilia spacing and cilia polarity as well as the timing of cilia beating during metachronal synchrony. The planar cell polarity pathway and hydrodynamic forces have been shown to instruct cilia polarity. In this paper, we show how intracellular effectors interpret polarity to organize cellular morphology in accordance with asymmetric cellular function. We observe that both cellular actin and microtubule networks undergo drastic reorganization, providing differential roles during the polarized organization of cilia. Using computational angular correlation analysis of cilia orientation, we report a graded cellular organization downstream of cell polarity cues. Actin dynamics are required for proper cilia spacing, global coordination of cilia polarity, and coordination of metachronic cilia beating, whereas cytoplasmic microtubule dynamics are required for local coordination of polarity between neighboring cilia.

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