Article

The mammalian Scribble polarity protein regulates epithelial cell adhesion and migration through E-cadherin

Center for Cell Signaling, Department of Microbiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 01/2006; 171(6):1061-71. DOI: 10.1083/jcb.200506094
Source: PubMed

ABSTRACT Scribble (Scrib) is a conserved polarity protein required in Drosophila melanogaster for synaptic function, neuroblast differentiation, and epithelial polarization. It is also a tumor suppressor. In rodents, Scrib has been implicated in receptor recycling and planar polarity but not in apical/basal polarity. We now show that knockdown of Scrib disrupts adhesion between Madin-Darby canine kidney epithelial cells. As a consequence, the cells acquire a mesenchymal appearance, migrate more rapidly, and lose directionality. Although tight junction assembly is delayed, confluent monolayers remain polarized. These effects are independent of Rac activation or Scrib binding to betaPIX. Rather, Scrib depletion disrupts E-cadherin-mediated cell-cell adhesion. The changes in morphology and migration are phenocopied by E-cadherin knockdown. Adhesion is partially rescued by expression of an E-cadherin-alpha-catenin fusion protein but not by E-cadherin-green fluorescent protein. These results suggest that Scrib stabilizes the coupling between E-cadherin and the catenins and are consistent with the idea that mammalian Scrib could behave as a tumor suppressor by regulating epithelial cell adhesion and migration.

0 Bookmarks
 · 
140 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The structure and function of the barrier layers restricting the free diffusion of substances between the central nervous system (brain and spinal cord) and the systemic circulation is of great medical interest as various pathological conditions often lead to their impairment. Excessive leakage of blood-borne molecules into the parenchyma and the concomitant fluctuations in the microenvironment following a transient breakdown of the blood-brain barrier (BBB) during ischemic/hypoxic conditions or because of an autoimmune disease are detrimental to the physiological functioning of nervous tissue. On the other hand, the treatment of neurological disorders is often hampered as only minimal amounts of therapeutic agents are able to penetrate a fully functional BBB or blood cerebrospinal fluid barrier. An in-depth understanding of the molecular machinery governing the establishment and maintenance of these barriers is necessary to develop rational strategies allowing a controlled delivery of appropriate drugs to the CNS. At the basis of such tissue barriers are intimate cell-cell contacts (zonulae occludentes, tight junctions) which are present in all polarized epithelia and endothelia. By creating a paracellular diffusion constraint TJs enable the vectorial transport across cell monolayers. More recent findings indicate that functional barriers are already established during development, protecting the fetal brain. As an understanding of the biogenesis of TJs might reveal the underlying mechanisms of barrier formation during ontogenic development numerous in vitro systems have been developed to study the assembly and disassembly of TJs. In addition, monitoring the stage-specific expression of TJ-associated proteins during development has brought much insight into the "developmental tightening" of tissue barriers. Over the last two decades a detailed molecular map of transmembrane and cytoplasmic TJ-proteins has been identified. These proteins not only form a cell-cell adhesion structure, but integrate various signaling pathways, thereby directly or indirectly impacting upon processes such as cell-cell adhesion, cytoskeletal rearrangement, and transcriptional control. This review will provide a brief overview on the establishment of the BBB during embryonic development in mammals and a detailed description of the ultrastructure, biogenesis, and molecular composition of epithelial and endothelial TJs will be given.
    Frontiers in Neuroscience 12/2014; 8:392. DOI:10.3389/fnins.2014.00392
  • [Show abstract] [Hide abstract]
    ABSTRACT: Epithelial-mesenchymal transition (EMT) promotes tumor invasion and metastasis, but the coordination and integration mechanisms of these processes are still not fully understood. In this study, we used a cross-species expression profiling strategy of Hela cells to determine an important genetic program transfers. In particular, we have discovered a new transfer function, which is not previously known about transcription factor forkhead box Q1 (FOXQ1). The shRNA anti-FOXQ1 gene was synthesized and transfected into the Hela and EpRas cells. RT-PCR assay was performed to detect the mRNA levels in cells. Cell adhesion and separation assay were used to examine the cell-cell adhesion and separation among cells. Wound healing assay was utilized to examine cell migration and invasion ability. Chromatin immunoprecipitation assay was used to investigate the interaction between E-cadherin and N-cadherin and FOXQ1 promoter region. The results indicated that ectopic expression of FOXQ1 increased cell migration and invasion in vitro, enhanced mammary epithelial cells in vivo lung metastasis, and triggered significant EMT. In contrast, the opposite effects in vitro and in vivo of FOXQ1 knockdown phenotypes were caused by these mechanisms. Notably, FOXQ1 repressed core EMT regulation of the expression of TGF-β1. FOXQ1 protein directly interacts with E-cadherin and N-cadherin promoter region. And surveys show that FOXQ1 expression regulation by TGF-β1 and blockade induced EMT both morphological and molecular levels. Our findings emphasize the feasibility of cross-species expression profiles, as a strategy to identify metastasis-related genes. The induction of EMT by FOXQ1 defines a new transfer function in promoting cancer behind possible mechanisms.
    Molecular and Cellular Biochemistry 10/2014; 397(1-2). DOI:10.1007/s11010-014-2185-1 · 2.39 Impact Factor
  • Source

Full-text (3 Sources)

Download
48 Downloads
Available from
May 15, 2014