scholarly journals Morphogenetic forces planar polarize LGN/Pins in the embryonic head during Drosophila gastrulation

2022 ◽  
Author(s):  
Jaclyn M Camuglia ◽  
Soline Chanet ◽  
Adam C Martin
Keyword(s):  
Planar Cell Polarity ◽  
Adherens Junction ◽  
Drosophila Embryo ◽  
Spindle Orientation ◽  
Planar Polarity ◽  
Ventral Furrow ◽  
Adherens Junction Protein ◽  
Early Drosophila Embryo ◽  
Junction Protein

Spindle orientation is often achieved by a complex of Pins/LGN, Mud/NuMa, Gαi, and Dynein, which interacts with astral microtubules to rotate the spindle. Cortical Pins/LGN recruitment serves as a critical step in this process. Here, we identify Pins-mediated planar cell polarized divisions in several of the mitotic domains of the early Drosophila embryo. We found that neither planar cell polarity pathways nor planar polarized myosin localization determined division orientation; instead, our findings strongly suggest that Pins planar polarity and force generated from mesoderm invagination are important. Disrupting Pins polarity via overexpression of a myristoylated version of Pins caused randomized division angles. We found that disrupting forces through chemical inhibitors, laser ablation, and depletion of an adherens junction protein disrupted Pins planar polarity and spindle orientation. Furthermore, snail depletion, which abrogates ventral furrow forces, disrupted Pins polarization and spindle orientation, suggesting that morphogenetic movements and resulting forces transmitted through the tissue can polarize Pins and orient division. Thus, morphogenetic forces associated with mesoderm invagination result in planar polarized Pins to mediate division orientation at a distant region of the embryo during morphogenesis. To our knowledge, this is the first in vivo example where mechanical force has been shown to polarize Pins to mediate division orientation.

scholarly journals PLEKHA7, an apical adherens junction protein, suppresses inflammatory breast cancer in the context of high E-cadherin and p120-catenin expression.

2020 ◽  
Author(s):  
Lindy J Pence ◽  
Antonis Kourtidis ◽  
Ryan W. Feathers ◽  
Mary T. Haddad ◽  
Sotiris Sotiriou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Line ◽  
Inflammatory Breast Cancer ◽  
Adherens Junction ◽  
Major Protein ◽  
Breast Cancers ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
E Cadherin

Abstract Background: Inflammatory breast cancer is a highly aggressive form of breast cancer that robustly forms clusters of tumor emboli in dermal lymphatics and readily metastasizes. Inflammatory breast cancers express high levels of E-cadherin, the major protein of adherens junctions, which may enhance the ability of tumor cells to form such clusters and contribute to metastasis. Seemingly contradictory, E-cadherin has both tumor-suppressing and tumor-promoting roles in cancer; previous studies suggest that this depends on the balance between apical and basolateral cadherin-catenin complexes. Methods: In the present study, we use immunohistochemistry of inflammatory breast cancer patient samples and biochemical analysis of cell lines to determine the expression of PLEKHA7, an apical adherens junction protein. We use viral transduction to ectopically express PLEKHA7 in the SUM149 inflammatory breast cancer cell line. The effect of PLEKHA7 on the aggressiveness of inflammatory breast cancer in 2D, 3D and in-vivo were examined. Results: We determined that PLEKHA7 was deregulated in inflammatory breast cancer, demonstrating improper localization or lost expression in a strong majority of patient samples and very low expression in cell line models. We found that re-expressing PLEKHA7 is sufficient to suppress proliferation, anchorage independent growth, spheroid viability, and tumor growth in-vivo. We also observed a negative-selection pressure within the xenograft tumors to lose PLEKHA7 function or expression.Conclusions: The data indicate that PLEKHA7 is frequently deregulated and acts as a suppressor of inflammatory breast cancer. They also suggest that the resulting imbalance between apical and basolateral cadherin-catenin complexes contributes to growth, survival and emboli-forming capacities of inflammatory breast cancer.

scholarly journals PLEKHA7, an Apical Adherens Junction Protein, Suppresses Inflammatory Breast Cancer in the Context of High E-Cadherin and p120-Catenin Expression

2021 ◽  
Vol 22 (3) ◽  
pp. 1275
Author(s):  
Lindy J. Pence ◽  
Antonis Kourtidis ◽  
Ryan W. Feathers ◽  
Mary T. Haddad ◽  
Sotiris Sotiriou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Inflammatory Breast Cancer ◽  
Driving Forces ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Tumor Emboli ◽  
E Cadherin

Inflammatory breast cancer is a highly aggressive form of breast cancer that forms clusters of tumor emboli in dermal lymphatics and readily metastasizes. These cancers express high levels of E-cadherin, the major mediator of adherens junctions, which enhances formation of tumor emboli. Previous studies suggest that E-cadherin promotes cancer when the balance between apical and basolateral cadherin complexes is disrupted. Here, we used immunohistochemistry of inflammatory breast cancer patient samples and analysis of cell lines to determine the expression of PLEKHA7, an apical adherens junction protein. We used viral transduction to re-express PLEKHA7 in inflammatory breast cancer cells and examined their aggressiveness in 2D and 3D cultures and in vivo. We determined that PLEKHA7 was deregulated in inflammatory breast cancer, demonstrating improper localization or lost expression in most patient samples and very low expression in cell lines. Re-expressing PLEKHA7 suppressed proliferation, anchorage independent growth, spheroid viability, and tumor growth in vivo. The data indicate that PLEKHA7 is frequently deregulated and acts to suppress inflammatory breast cancer. The data also promote the need for future inquiry into the imbalance between apical and basolateral cadherin complexes as driving forces in inflammatory breast cancer.

scholarly journals An in vivo structure-function study of armadillo, the beta-catenin homologue, reveals both separate and overlapping regions of the protein required for cell adhesion and for wingless signaling.

1996 ◽  
Vol 134 (5) ◽  
pp. 1283-1300 ◽  
Author(s):  
S Orsulic ◽  
M Peifer
Keyword(s):  
Structure Function ◽  
Cellular Localization ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Beta Catenin ◽  
Function Study ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Wingless Signaling

Armadillo, the Drosophila homologue of vertebrate beta-catenin, plays a pivotal role both in Wingless signaling and in assembly of adherens junctions. We performed the first in vivo structure-function study of an adherens junction protein, by generating and examining a series of Armadillo mutants in the context of the entire animal. We tested each mutant by assaying its biological function, its ability to bind proteins that normally associate with Armadillo in adherens junctions, its cellular localization, and its pattern of phosphorylation. We mapped the binding sites for DE-cadherin and alpha-catenin. Although these bind to Armadillo independently of each other, binding of each is required for the function of adherens junctions. We identified two separate regions of Armadillo critical for Wingless signaling. We demonstrated that endogenous Armadillo accumulates in the nucleus and provide evidence that it may act there in transducing Wingless signal. We found that the Arm repeats, which make up the central two-thirds of Armadillo, differ among themselves in their functional importance in different processes. Finally, we demonstrated that Armadillo's roles in adherens junctions and Wingless signaling are independent. We discuss the potential biochemical role of Armadillo in each process.

116. Contribution of claudin-11 to the inter-Sertoli cell tight junction, in vitro

2005 ◽  
Vol 17 (9) ◽  
pp. 72
Author(s):  
M. J. McCabe ◽  
P. G. Stanton
Keyword(s):  
Tight Junction ◽  
Mrna Expression ◽  
Sertoli Cell ◽  
Adhesion Molecule ◽  
Sertoli Cells ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein

The inter-Sertoli cell tight junction (TJ) forms the blood testis barrier (BTB) between Sertoli cells and is composed of three major transmembrane proteins: claudin-11, occludin and junctional adhesion molecule. Formation of the BTB occurs during puberty associating with an increase in circulating gonadotrophins. Claudin-11 and occludin are hormonally regulated in vitro although their importance to the function of the TJ is unknown. The aim of this study was to investigate the contribution of claudin-11 to the inter-Sertoli cell TJ in vitro by blocking gene expression using RNA interference. Two claudin-11-specific siRNA fragments were designed for this purpose. Sertoli cells in primary culture formed stable TJs within 5 days as measured by transepithelial electrical resistance (TER). The addition of siRNA for 2 days resulted in a significant (P < 0.01) 55% (mean, SD, n = 4 cultures) decrease in TER along with a major reduction in claudin-11 localisation to the TJ as assessed by immunocytochemistry. The specificity of the siRNA was shown by the presence of extensive immunostaining of occludin and of the adherens junction protein β-catenin in the same treatments. Similarly, claudin-11 mRNA expression significantly (P < 0.01) decreased by 71% (mean, SD, n = 3 cultures) in response to both claudin-11 siRNA fragments. Occludin mRNA expression was not affected. It is concluded that claudin-11 contributes at least 55% to the function of the rat Sertoli cell TJ in vitro. It is hypothesised that the remaining 45% of TJ function can be attributed to other integral proteins, such as occludin and junctional adhesion molecule. It is expected that claudin-11 and other TJ proteins play a pivotal role in the function of the BTB in vivo with potential implications in fertility and contraception.

scholarly journals The AF-6 Homolog Canoe Acts as a Rap1 Effector During Dorsal Closure of the Drosophila Embryo

Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 159-169
Author(s):  
Benjamin Boettner ◽  
Phoebe Harjes ◽  
Satoshi Ishimaru ◽  
Michael Heke ◽  
Hong Qing Fan ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Genetic Interaction ◽  
Critical Role ◽  
Adherens Junction ◽  
Small Gtpases ◽  
Drosophila Embryo ◽  
Dorsal Closure ◽  
Cell Sheets ◽  
Jnk Pathway

Abstract Rap1 belongs to the highly conserved Ras subfamily of small GTPases. In Drosophila, Rap1 plays a critical role in many different morphogenetic processes, but the molecular mechanisms executing its function are unknown. Here, we demonstrate that Canoe (Cno), the Drosophila homolog of mammalian junctional protein AF-6, acts as an effector of Rap1 in vivo. Cno binds to the activated form of Rap1 in a yeast two-hybrid assay, the two molecules colocalize to the adherens junction, and they display very similar phenotypes in embryonic dorsal closure (DC), a process that relies on the elongation and migration of epithelial cell sheets. Genetic interaction experiments show that Rap1 and Cno act in the same molecular pathway during DC and that the function of both molecules in DC depends on their ability to interact. We further show that Rap1 acts upstream of Cno, but that Rap1, unlike Cno, is not involved in the stimulation of JNK pathway activity, indicating that Cno has both a Rap1-dependent and a Rap1-independent function in the DC process.

scholarly journals β-Catenin is a pH sensor with decreased stability at higher intracellular pH

2018 ◽  
Vol 217 (11) ◽  
pp. 3965-3976 ◽  
Author(s):  
Katharine A. White ◽  
Bree K. Grillo-Hill ◽  
Mario Esquivel ◽  
Jobelle Peralta ◽  
Vivian N. Bui ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Ph Sensor ◽  
Adherens Junction ◽  
Protein Protein Interactions ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Evolutionarily Conserved ◽  
Ph Dependent

β-Catenin functions as an adherens junction protein for cell–cell adhesion and as a signaling protein. β-catenin function is dependent on its stability, which is regulated by protein–protein interactions that stabilize β-catenin or target it for proteasome-mediated degradation. In this study, we show that β-catenin stability is regulated by intracellular pH (pHi) dynamics, with decreased stability at higher pHi in both mammalian cells and Drosophila melanogaster. β-Catenin degradation requires phosphorylation of N-terminal residues for recognition by the E3 ligase β-TrCP. While β-catenin phosphorylation was pH independent, higher pHi induced increased β-TrCP binding and decreased β-catenin stability. An evolutionarily conserved histidine in β-catenin (found in the β-TrCP DSGIHS destruction motif) is required for pH-dependent binding to β-TrCP. Expressing a cancer-associated H36R–β-catenin mutant in the Drosophila eye was sufficient to induce Wnt signaling and produced pronounced tumors not seen with other oncogenic β-catenin alleles. We identify pHi dynamics as a previously unrecognized regulator of β-catenin stability, functioning in coincidence with phosphorylation.

Sign in / Sign up

Export Citation Format

Share Document