Ischemia-Induced Loss of Epithelial Polarity

MARK2 regulates the establishment of polarity in Madin–Darby canine kidney (MDCK) cells in part through phosphorylation of serine 227 of Rab11-FIP2. We identified Eps15 as an interacting partner of phospho-S227-Rab11-FIP2 (pS227-FIP2). During recovery from low calcium, Eps15 localized to the lateral membrane before pS227-FIP2 arrival. Later in recovery, Eps15 and pS227-FIP2 colocalized at the lateral membrane. In MDCK cells expressing the pseudophosphorylated FIP2 mutant FIP2(S227E), during recovery from low calcium, Eps15 was trapped and never localized to the lateral membrane. Mutation of any of the three NPF domains within GFP-FIP2(S227E) rescued Eps15 localization at the lateral membrane and reestablished single-lumen cyst formation in GFP-FIP2(S227E)–expressing cells in three-dimensional (3D) culture. Whereas expression of GFP-FIP2(S227E) induced the loss of E-cadherin and occludin, mutation of any of the NPF domains of GFP-FIP2(S227E) reestablished both proteins at the apical junctions. Knockdown of Eps15 altered the spatial and temporal localization of pS227-FIP2 and also elicited formation of multiple lumens in MDCK 3D cysts. Thus an interaction of Eps15 and pS227-FIP2 at the appropriate time and location in polarizing cells is necessary for proper establishment of epithelial polarity.

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Tissue-specific function of Patj in regulating the Crumbs complex and epithelial polarity

Development ◽

10.1242/dev.085449 ◽

2012 ◽

Vol 139 (24) ◽

pp. 4549-4554 ◽

Cited By ~ 15

Author(s):

C. Penalva ◽

V. Mirouse

Keyword(s):

Epithelial Polarity ◽

Specific Function ◽

Tissue Specific ◽

Crumbs Complex

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c-erbB-3

The Journal of Cell Biology ◽

10.1083/jcb.200109033 ◽

2002 ◽

Vol 157 (6) ◽

pp. 929-940 ◽

Cited By ~ 145

Author(s):

Martin Offterdinger ◽

Christian Schöfer ◽

Klara Weipoltshammer ◽

Thomas W. Grunt

Keyword(s):

Epithelial Cells ◽

Nuclear Localization ◽

Nuclear Export ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Site Directed Mutagenesis ◽

Receptor Protein ◽

Erbb Receptors ◽

Cell Fractionation ◽

Epithelial Polarity

c-erbB receptors are usually located in cell membranes and are activated by extracellular binding of EGF-like growth factors. Unexpectedly, using immunofluorescence we found high levels of c-erbB-3 within the nuclei of MTSV1-7 immortalized nonmalignant human mammary epithelial cells. Nuclear localization was mediated by the COOH terminus of c-erbB-3, and a nuclear localization signal was identified by site-directed mutagenesis and by transfer of the signal to chicken pyruvate kinase. A nuclear export inhibitor caused accumulation of c-erbB-3 in the nuclei of other mammary epithelial cell lines as demonstrated by immunofluorescence and biochemical cell fractionation, suggesting that c-erbB-3 shuttles between nuclear and nonnuclear compartments in these cells. Growth of MTSV1-7 on permeable filters induced epithelial polarity and concentration of c-erbB-3 within the nucleoli. However, the c-erbB-3 ligand heregulin β1 shifted c-erbB-3 from the nucleolus into the nucleoplasm and then into the cytoplasm. The subcellular localization of c-erbB-3 obviously depends on exogenous stimuli and on the stage of epithelial polarity and challenges the specific function of c-erbB-3 as a transmembrane receptor protein arguing for additional, as yet unidentified, roles of c-erbB-3 within the nucle(ol)us of mammary epithelial cells.

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Renal epithelial polarity in health and disease

Pediatric Nephrology ◽

10.1007/s004670050586 ◽

1999 ◽

Vol 13 (2) ◽

pp. 163-170 ◽

Cited By ~ 27

Author(s):

Mark C. Wagner ◽

B. A. Molitoris

Keyword(s):

Epithelial Polarity ◽

Health And Disease

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CD13 orients the apical-basal polarity axis necessary for lumen formation

Nature Communications ◽

10.1038/s41467-021-24993-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Li-Ting Wang ◽

Abira Rajah ◽

Claire M. Brown ◽

Luke McCaffrey

Keyword(s):

Epithelial Cells ◽

Apical Membrane ◽

Initiation Site ◽

Outer Cell ◽

Cell Periphery ◽

Complex Structures ◽

Peptidase Activity ◽

Epithelial Polarity ◽

Lumen Formation ◽

Apical Domain

AbstractPolarized epithelial cells can organize into complex structures with a characteristic central lumen. Lumen formation requires that cells coordinately orient their polarity axis so that the basolateral domain is on the outside and apical domain inside epithelial structures. Here we show that the transmembrane aminopeptidase, CD13, is a key determinant of epithelial polarity orientation. CD13 localizes to the apical membrane and associates with an apical complex with Par6. CD13-deficient cells display inverted polarity in which apical proteins are retained on the outer cell periphery and fail to accumulate at an intercellular apical initiation site. Here we show that CD13 is required to couple apical protein cargo to Rab11-endosomes and for capture of endosomes at the apical initiation site. This role in polarity utilizes the short intracellular domain but is independent of CD13 peptidase activity.

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LKB1 and AMPK maintain epithelial cell polarity under energetic stress

The Journal of Cell Biology ◽

10.1083/jcb.200702053 ◽

2007 ◽

Vol 177 (3) ◽

pp. 387-392 ◽

Cited By ~ 134

Author(s):

Vincent Mirouse ◽

Lance L. Swick ◽

Nevzat Kazgan ◽

Daniel St Johnston ◽

Jay E. Brenman

Keyword(s):

Tumor Suppressor ◽

Cell Polarity ◽

Growth Control ◽

Epithelial Polarity ◽

Energy Status ◽

Ampk Signaling ◽

Cellular Energy ◽

Energetic Stress ◽

Stress Dependent

LKB1 is mutated in both familial and spontaneous tumors, and acts as a master kinase that activates the PAR-1 polarity kinase and the adenosine 5′monophosphate–activated kinase (AMPK). This has led to the hypothesis that LKB1 acts as a tumor suppressor because it is required to maintain cell polarity and growth control through PAR-1 and AMPK, respectively. However, the genetic analysis of LKB1–AMPK signaling in vertebrates has been complicated by the existence of multiple redundant AMPK subunits. We describe the identification of mutations in the single Drosophila melanogaster AMPK catalytic subunit AMPKα. Surprisingly, ampkα mutant epithelial cells lose their polarity and overproliferate under energetic stress. LKB1 is required in vivo for AMPK activation, and lkb1 mutations cause similar energetic stress–dependent phenotypes to ampkα mutations. Furthermore, lkb1 phenotypes are rescued by a phosphomimetic version of AMPKα. Thus, LKB1 signals through AMPK to coordinate epithelial polarity and proliferation with cellular energy status, and this might underlie the tumor suppressor function of LKB1.

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Tankyrase regulates epithelial lumen formation via suppression of Rab11 GEFs

The Journal of Cell Biology ◽

10.1083/jcb.202008037 ◽

2021 ◽

Vol 220 (7) ◽

Author(s):

Arun A. Chandrakumar ◽

Étienne Coyaud ◽

Christopher B. Marshall ◽

Mitsuhiko Ikura ◽

Brian Raught ◽

...

Keyword(s):

Guanine Nucleotide Exchange Factors ◽

Protein Abundance ◽

Epithelial Polarity ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Lumen Formation ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factors ◽

Interaction Proteomics ◽

Sequential Inhibition

Rab11 GTPase proteins are required for cytokinesis, ciliogenesis, and lumenogenesis. Rab11a is critical for apical delivery of podocalyxin (PODXL) during lumen formation in epithelial cells. SH3BP5 and SH3BP5L are guanine nucleotide exchange factors (GEFs) for Rab11. We show that SH3BP5 and SH3BP5L are required for activation of Rab11a and cyst lumen formation. Using proximity-dependent biotin identification (BioID) interaction proteomics, we have identified SH3BP5 and its paralogue SH3BP5L as new substrates of the poly-ADP-ribose polymerase Tankyrase and the E3 ligase RNF146. We provide data demonstrating that epithelial polarity via cyst lumen formation is governed by Tankyrase, which inhibits Rab11a activation through the suppression of SH3BP5 and SH3BP5L. RNF146 reduces Tankyrase protein abundance and restores Rab11a activation and lumen formation. Thus, Rab11a activation is controlled by a signaling pathway composed of the sequential inhibition of SH3BP5 paralogues by Tankyrase, which is itself suppressed by RNF146.

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