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Yan C Cheng - One of the best experts on this subject based on the ideXlab platform.
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biology and regulation of ectoplasmic specialization an atypical Adherens Junction type in the testis
Biochimica et Biophysica Acta, 2008Co-Authors: Elissa W P Wong, Dolores D Mruk, Yan C ChengAbstract:Anchoring Junctions are cell adhesion apparatus present in all epithelia and endothelia. They are found at the cell-cell interface (Adherens Junction (AJ) and desmosome) and cell-matrix interface (focal contact and hemidesmosome). In this review, we focus our discussion on AJ in particular the dynamic changes and regulation of this Junction type in normal epithelia using testis as a model. There are extensive restructuring of AJ (e.g., ectoplasmic specialization, ES, a testis-specific AJ) at the Sertoli-Sertoli cell interface (basal ES) and Sertoli-elongating spermatid interface (apical ES) during the seminiferous epithelial cycle of spermatogenesis to facilitate the migration of developing germ cells across the seminiferous epithelium. Furthermore, recent findings have shown that ES also confers cell orientation and polarity in the seminiferous epithelium, illustrating that some of the functions initially ascribed to tight Junctions (TJ), such as conferring cell polarity, are also part of the inherent properties of the AJ (e.g., apical ES) in the testis. The biology and regulation based on recent studies in the testis are of interest to cell biologists in the field, in particular their regulation, which perhaps is applicable to tumorigenesis.
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mitogen activated protein kinases Adherens Junction dynamics and spermatogenesis a review of recent data
Developmental Biology, 2005Co-Authors: Chinghang Wong, Yan C ChengAbstract:Mitogen-activated protein kinases (MAPKs) are important regulators of many cellular processes. In mammalian testes, these kinases are involved in controlling cell division, differentiation, survival and death, and are therefore critical to spermatogenesis. Recent studies have also illustrated their involvement in Junction restructuring in the seminiferous epithelium, especially at the ectoplasmic specialization (ES), a testis-specific Adherens Junction (AJ) type. ES contributes to the adhesion between Sertoli cells at the blood-testis barrier, as well as between Sertoli and developing spermatids (step 9 and beyond) at the adluminal compartment. MAPKs regulate AJ dynamics in the testis via their effects on the turnover of Junction-associated protein complexes, the production of proteases and protease inhibitors, and the cytoskeleton structure. In this review, roles of the three major MAPK members, namely extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK, in ES dynamics are critically discussed. An integrated model of how these three MAPKs regulate adhesion function in the seminiferous epithelium is also presented. This model will serve as the framework for future investigation in the field.
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regulation of sertoli germ cell Adherens Junction dynamics via changes in protein protein interactions of the n cadherin β catenin protein complex which are possibly mediated by c src and myotubularin related protein 2 an in vivo study using an andro
Endocrinology, 2005Co-Authors: Jiayi Zhang, Chinghang Wong, Dolores D Mruk, Nikki P Y Lee, Weiliang Xia, Will M Lee, Yan C ChengAbstract:Using a well characterized model of cell-cell actin-based Adherens Junction (AJ) disruption by suppressing the intratesticular testosterone level in adult rats with testosterone-estradiol implants, we have confirmed earlier findings that Sertoli-germ cell AJ dynamics are regulated by the activation of kinases via putative signaling pathways but with some unexpected findings as follows. First, the loss of germ cells from the seminiferous epithelium during androgen suppression was associated with a surge in myotubularin-related protein 2 (MTMR2, a lipid phosphatase, in which adult MTMR2−/− mice were recently shown to be azoospermic because of the loss of cell adhesion function between germ and Sertoli cells); kinases: phosphatidylinositol 3-kinase, c-Src, and C-terminal Src kinase; adaptors: α-actinin, vinculin, afadin, and p130 Crk-associated protein; and AJ-integral membrane proteins at the ectoplasmic specialization (ES, a testis-specific cell-cell actin-based AJ type) site: N-cadherin, β-catenin, integr...
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protein kinases and Adherens Junction dynamics in the seminiferous epithelium of the rat testis
Journal of Cellular Physiology, 2005Co-Authors: Nikki P Y Lee, Yan C ChengAbstract:Earlier studies in multiple epithelia have shown that cell–cell actin-based Adherens Junction (AJ) dynamics are regulated, at least in part, by the interplay of kinases and phosphatases that determines the intracellular phosphoprotein content. Yet it is virtually unknown regarding the role of protein kinases in Sertoli–germ cell AJ dynamics in the seminiferous epithelium of the testis. To address this issue, an in vitro coculture system utilizing Sertoli and germ cells was used to study the regulation of several protein kinases, including c-Src (the cellular form of the v-src transforming gene of Rous Sarcoma virus, RSV), carboxyl-terminal Src kinase (Csk), and casein kinase 2 (CK2), during AJ assembly. Both Sertoli and germ cells were shown to express c-Src, Csk, and CK2 with a relative Sertoli:germ cell ratio of ∼1:1, suggesting both cell types contributed equally to the pool of these kinases in the epithelium. c-Src and Csk were shown to be stage-specific proteins during the epithelial cycle, being highest at stages VII–VIII. Studies using immunoprecipitation have illustrated that these kinases were structurally associated with the N-cadherin/β-catenin, but not the nectin/afadin, protein complex, implicating that the cadherin/catenin protein complex is their likely putative substrate. An induction in c-Src, Csk, and CK2 were detected during Sertoli–germ cell AJ assembly in vitro but not when Sertoli cells were cultured alone. When adult rats were treated with 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide (AF-2364), a compound known to induce germ cell loss from the seminiferous epithelium, in particular elongating/elongate and round spermatids, by disrupting Sertoli–germ cell AJs, an induction of c-Src and Csk, but not CK2, was detected. Furthermore, a transient increase in the intrinsic kinase activities of c-Src, but not CK2, was also detected. This event was also associated with a loss of protein–protein association of N-cadherin and β-catenin from the cadherin/catenin/c-Src/Csk/CK2 protein complex. Administration of PP1, a c-Src inhibitor, into adult rats via the jugular vein could induce the loss of spermatocytes and round spermatids, but not elongating/elongate spermatids, from the seminiferous epithelium. This result thus implicates the importance of c-Src in maintaining the integrity of AJs and possibly desmosome-like Junctions between Sertoli cells and spermatocytes/round spermatids. In short, the data reported herein have shown that c-Src, Csk, and CK2 are novel protein kinases in AJ dynamics in the testis. © 2004 Wiley-Liss, Inc.
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ectoplasmic specialization a testis specific cell cell actin based Adherens Junction type is this a potential target for male contraceptive development
Human Reproduction Update, 2004Co-Authors: Nikki P Y Lee, Yan C ChengAbstract:The seminiferous tubule of the mammalian testis is largely composed of Sertoli and germ cells, which coordinate with Leydig cells in the interstitium and perform two major physiological functions, namely spermatogenesis and steroidogenesis respectively. Each tubule is morphologically divided into (i) the seminiferous epithelium composing Sertoli and germ cells, and (ii) the basement membrane (a modified form of extracellular matrix); underneath this lies the collagen fibril network, the myoid cell layer, and the lymphatic vessel, which collectively constitute the tunica propia. In the seminiferous epithelium, of rodent testes each type A1 spermatogonium (diploid, 2n) differentiates into 256 elongated spermatids (haploid, 1n) during spermatogenesis. Additionally, developing germ cells must migrate progressively from the basal to the luminal edge of the adluminal compartment so that fully developed spermatids can be released into the lumen at spermiation. Without this timely event of cell movement, spermatogenesis cannot reach completion and infertility will result. Yet developing round elongating/elongated spermatids must remain attached to the epithelium via a specialized Sertoli‐ germ cell actin-based Adherens Junction (AJ) type known as ectoplasmic specialization (ES), which is crucial not only for cell attachment but also for spermatid movement and orientation in the epithelium. However, the biochemical composition and molecular architecture of the protein complexes that constitute the ES have only recently been studied. Furthermore, the signalling pathways that regulate ES dynamics are virtually unknown. This review highlights recent advances in these two areas of research. It is expected that, if adequately expanded, these studies should yield new insights into the development of novel contraceptives targeted to perturb ES function in the testis. The potential to specifically target the ES may also mean that contraceptive action could be achieved without perturbing the hypothalamic‐pituitary ‐testicular axis.
Peter Mundel - One of the best experts on this subject based on the ideXlab platform.
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the glomerular slit diaphragm is a modified Adherens Junction
Journal of The American Society of Nephrology, 2000Co-Authors: Jochen Reiser, Wilhelm Kriz, Matthias Kretzler, Peter MundelAbstract:Abstract . The glomerular slit diaphragm between podocyte foot processes shares typical morphologic features with an Adherens Junction. Differentiated cultured podocytes form cellular structures comparable to filtration slits in vivo . At those sites, zonula occludens-1 (ZO-1) was coexpressed with P-cadherin as well as with α-, β-, and γ-catenin. In situ , P-cadherin was detected at the slit diaphragm in association with ZO-1 as shown by confocal microscopy and immunogold double labeling electron microscopy. P-cadherin expression in vivo and in vitro was confirmed by reverse transcription-PCR. These findings led to the concept that the slit diaphragm represents an Adherens Junction composed of P-cadherin, α-, β-, and γ-catenin, and ZO-1. In contrast to an Adherens Junction of a similar composition recently described in cultured fibroblasts, the slit diaphragm complex does not contain vinculin, which was found in nearby focal contacts. A P-cadherinbased Adherens Junction is well-suited to explain the zipper-like structure of the slit diaphragm. The present study should allow new avenues leading to the identification of additional slit diaphragm-associated proteins conferring specificity to this unique cell Junction.
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the glomerular slit diaphragm is a modified Adherens Junction
Journal of The American Society of Nephrology, 2000Co-Authors: Jochen Reiser, Wilhelm Kriz, Matthias Kretzler, Peter MundelAbstract:The glomerular slit diaphragm between podocyte foot processes shares typical morphologic features with an Adherens Junction. Differentiated cultured podocytes form cellular structures comparable to filtration slits in vivo. At those sites, zonula occludens-1 (ZO-1) was coexpressed with P-cadherin as well as with alpha-, beta-, and gamma-catenin. In situ, P-cadherin was detected at the slit diaphragm in association with ZO-1 as shown by confocal microscopy and immunogold double labeling electron microscopy. P-cadherin expression in vivo and in vitro was confirmed by reverse transcription-PCR. These findings led to the concept that the slit diaphragm represents an Adherens Junction composed of P-cadherin, alpha-, beta-, and gamma-catenin, and ZO-1. In contrast to an Adherens Junction of a similar composition recently described in cultured fibroblasts, the slit diaphragm complex does not contain vinculin, which was found in nearby focal contacts. A P-cadherin-based Adherens Junction is well-suited to explain the zipper-like structure of the slit diaphragm. The present study should allow new avenues leading to the identification of additional slit diaphragm-associated proteins conferring specificity to this unique cell Junction.
Haiyan Xu - One of the best experts on this subject based on the ideXlab platform.
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Comparative study of in vitro effects of different nanoparticles at non-cytotoxic concentration on the Adherens Junction of human vascular endothelial cells
International Journal of Nanomedicine, 2019Co-Authors: Aiyun Yang, Lifan Du, Lingyu Piao, Jie Meng, Haiyan XuAbstract:Effects of different nanoparticles (NPs) exposure at acutely non-cytotoxic concentrations are particularly worthy to figure out, compare, and elucidate. To investigate and compare the effect of a small library of NPs at non-cytotoxic concentration on the Adherens Junction of human umbilical vein endothelial cells (HUVECs), obtaining new insights of NPs safety evaluation. The HUVECs layer was exposed to NPs including gold (Au), platinum (Pt), silica (SiO2), titanium dioxide (TiO2), ferric oxide (Fe2O3), oxidized multi-walled carbon nanotubes, with different surface chemistry and size distribution. Cellular uptake of NPs was observed by transmission electron microscopy. and the cytotoxicity was determined by Cell Counting Kit-8 assay. The NP-induced variation of intracellular reactive oxygen species (ROS) and catalase (CAT) activity was measured using the probe of 2'7'-dichlorodihydr fluorescein diacetate and a CAT analysis kit, respectively. The level of VE-cadherin of HUVECs was analyzed by Western blot, and the loss of Adherens Junction was observed with laser confocal microscopy. The acutely non-cytotoxic concentrations of different NPs were determined and applied to HUVECs. The NPs increased the level of intracellular ROS and the activity of CAT to different degrees, depending on the characteristics. At the same time, the HUVECs lost their Adherens Junction protein VE-cadherin and gaps were formed between the cells. The NP-induced oxidative stress and gap formation could be rescued by the supplementary N-acetylcysteine in the incubation. The increase of intracellular ROS and CAT activity was one common effect of NPs, even at the non-cytotoxic concentration, and the degree was dependent on the composition, surface chemistry, and size distribution of the NP. The effect led to the gap formation between the cells, while could be rescued by the antioxidant. Therefore, the variation of Adherens Junction between endothelial cells was suggested to evaluate for NPs when used as therapeutics and diagnostics.
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comparative study of in vitro effects of different nanoparticles at non cytotoxic concentration on the Adherens Junction of human vascular endothelial cells
International Journal of Nanomedicine, 2019Co-Authors: Aiyun Yang, Lifan Du, Lingyu Piao, Jie Meng, Haiyan XuAbstract:Background: Effects of different nanoparticles (NPs) exposure at acutely non-cytotoxic concentrations are particularly worthy to figure out, compare, and elucidate. Objective: To investigate and compare the effect of a small library of NPs at non-cytotoxic concentration on the Adherens Junction of human umbilical vein endothelial cells (HUVECs), obtaining new insights of NPs safety evaluation. Materials and methods: The HUVECs layer was exposed to NPs including gold (Au), platinum (Pt), silica (SiO2), titanium dioxide (TiO2), ferric oxide (Fe2O3), oxidized multi-walled carbon nanotubes, with different surface chemistry and size distribution. Cellular uptake of NPs was observed by transmission electron microscopy. and the cytotoxicity was determined by Cell Counting Kit-8 assay. The NP-induced variation of intracellular reactive oxygen species (ROS) and catalase (CAT) activity was measured using the probe of 2'7'-dichlorodihydr fluorescein diacetate and a CAT analysis kit, respectively. The level of VE-cadherin of HUVECs was analyzed by Western blot, and the loss of Adherens Junction was observed with laser confocal microscopy. Results: The acutely non-cytotoxic concentrations of different NPs were determined and applied to HUVECs. The NPs increased the level of intracellular ROS and the activity of CAT to different degrees, depending on the characteristics. At the same time, the HUVECs lost their Adherens Junction protein VE-cadherin and gaps were formed between the cells. The NP-induced oxidative stress and gap formation could be rescued by the supplementary N-acetylcysteine in the incubation. Conclusion: The increase of intracellular ROS and CAT activity was one common effect of NPs, even at the non-cytotoxic concentration, and the degree was dependent on the composition, surface chemistry, and size distribution of the NP. The effect led to the gap formation between the cells, while could be rescued by the antioxidant. Therefore, the variation of Adherens Junction between endothelial cells was suggested to evaluate for NPs when used as therapeutics and diagnostics.
Kenneth S. Kosik - One of the best experts on this subject based on the ideXlab platform.
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δ catenin at the synaptic Adherens Junction
Trends in Cell Biology, 2005Co-Authors: Kenneth S. Kosik, Christine P. Donahue, Inbal Israely, Xin Liu, Tomoyo OchiishiAbstract:δ-catenin belongs to the p120-catenin (p120 ctn ) protein family, which is characterized by ten, characteristically spaced Armadillo repeats that bind to the juxtamembrane segment of the classical cadherins. δ-catenin is the only member of this family that is expressed specifically in neurons, where it binds to PDZ domain proteins in the post-synaptic compartment. As a component of both Adherens and synaptic Junctions, δ-catenin can link the Adherens Junction to the synapse and, thereby, coordinate synaptic input with changes in the Adherens Junction. By virtue of its restriction to the post-synaptic area, δ-catenin creates an asymmetric Adherens Junction in the region of the synapse. The crucial nature of the specialized function of δ-catenin in neurons is demonstrated by a targeted gene mutation, which causes deficits in learning and in synaptic plasticity. Taken together, recent evidence indicates that δ-catenin is a sensor of synaptic activity and implements activity-related morphological changes at the synapse.
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δ-Catenin at the synaptic–Adherens Junction
Trends in cell biology, 2005Co-Authors: Kenneth S. Kosik, Christine P. Donahue, Inbal Israely, Xin Liu, Tomoyo OchiishiAbstract:δ-catenin belongs to the p120-catenin (p120 ctn ) protein family, which is characterized by ten, characteristically spaced Armadillo repeats that bind to the juxtamembrane segment of the classical cadherins. δ-catenin is the only member of this family that is expressed specifically in neurons, where it binds to PDZ domain proteins in the post-synaptic compartment. As a component of both Adherens and synaptic Junctions, δ-catenin can link the Adherens Junction to the synapse and, thereby, coordinate synaptic input with changes in the Adherens Junction. By virtue of its restriction to the post-synaptic area, δ-catenin creates an asymmetric Adherens Junction in the region of the synapse. The crucial nature of the specialized function of δ-catenin in neurons is demonstrated by a targeted gene mutation, which causes deficits in learning and in synaptic plasticity. Taken together, recent evidence indicates that δ-catenin is a sensor of synaptic activity and implements activity-related morphological changes at the synapse.
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delta catenin is a nervous system specific Adherens Junction protein which undergoes dynamic relocalization during development
The Journal of Comparative Neurology, 2000Co-Authors: Jianhua Zhou, Miguel Medina, Tomohide Goto, Margaretha Jacobson, Pradeep G Bhide, Kenneth S. KosikAbstract:delta-catenin is a member of the Armadillo repeat family and component of the Adherens Junction discovered in a two-hybrid assay as a bona fide interactor with presenilin-1 (Zhou et al., [1997], NeuroReport 8:2085-2090), a protein which carries mutations that cause familial Alzheimer's disease. The expression pattern of delta-catenin was mapped between embryonic day 10 (E10) and adulthood by Northern blots, in situ hybridization and immunohistochemistry in the mouse. In development, delta-catenin is dynamically regulated with respect to its site of expression. It is first expressed within proliferating neuronal progenitor cells of the neuroepithelium, becomes down-regulated during neuronal migration, and is later reexpressed in the dendritic compartment of postmitotic neurons. In the mouse, delta-catenin mRNA is expressed by E10, increases and peaks at postnatal day (P)7, with lower levels in adulthood. In the developing neocortex, delta-catenin mRNA is strongly expressed in the proliferative ventricular zone and the developing cortical plate, yet is conspicuously less prominent in the intermediate zone, which contains migrating cortical neurons, delta-catenin protein forms a honeycomb pattern in the neuroepithelium by labeling the cell periphery in a typical Adherens Junction pattern. By E18, delta-catenin expression shifts primarily to nascent apical dendrites, a pattern that continues through adulthood. The dynamic relocalization of delta-catenin expression during development, taken together with previously published data which described a role for delta-catenin in cell motility (Lu et al., [1999] J. Cell. Biol. 144:519-532), suggests the hypothesis that delta-catenin regulation is closely linked to neuronal migration and may play a role in the establishment of mature dendritic relationships in the neuropil.
Mark Peifer - One of the best experts on this subject based on the ideXlab platform.
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the drosophila afadin and zo 1 homologues canoe and polychaetoid act in parallel to maintain epithelial integrity when challenged by Adherens Junction remodeling
Molecular Biology of the Cell, 2019Co-Authors: Lathiena Manning, Kia Z Perezvale, Kristina N Schaefer, Mycah T Sewell, Mark PeiferAbstract:During morphogenesis, cells must change shape and move without disrupting tissue integrity. This requires cell–cell Junctions to allow dynamic remodeling while resisting forces generated by the actomyosin cytoskeleton. Multiple proteins play roles in Junctional–cytoskeletal linkage, but the mechanisms by which they act remain unclear. Drosophila Canoe maintains Adherens Junction–cytoskeletal linkage during gastrulation. Canoe’s mammalian homologue Afadin plays similar roles in cultured cells, working in parallel with ZO-1 proteins, particularly at multicellular Junctions. We take these insights back to the fly embryo, exploring how cells maintain epithelial integrity when challenged by Adherens Junction remodeling during germband extension and dorsal closure. We found that Canoe helps cells maintain Junctional–cytoskeletal linkage when challenged by the Junctional remodeling inherent in mitosis, cell intercalation, and neuroblast invagination or by forces generated by the actomyosin cable at the leading edge. However, even in the absence of Canoe, many cells retain epithelial integrity. This is explained by a parallel role played by the ZO-1 homologue Polychaetoid. In embryos lacking both Canoe and Polychaetoid, cell Junctions fail early, with multicellular Junctions especially sensitive, leading to widespread loss of epithelial integrity. Our data suggest that Canoe and Polychaetoid stabilize Bazooka/Par3 at cell–cell Junctions, helping maintain balanced apical contractility and tissue integrity.
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scribble and discs large direct Adherens Junction positioning and supermolecular assembly to establish apical basal polarity
bioRxiv, 2019Co-Authors: Teresa T Bonello, Mark PeiferAbstract:Abstract Apical-basal polarity is a fundamental property of animal tissues. The Drosophila embryo provides an outstanding model for defining mechanisms that initiate and maintain polarity. Polarity is initiated during cellularization, when cell-cell Adherens Junctions are positioned at the future boundary of apical and basolateral domains. Polarity maintenance then involves complementary and antagonistic interplay between apical and basal polarity complexes. The Scribble/Dlg module is well-known for promoting basolateral identity during polarity maintenance. Here we report a surprising role for the Scribble/Dlg module in polarity initiation, placing it at the top of the network that positions Adherens Junctions. Scribble and Dlg are enriched in nascent Adherens Junctions and are essential for Adherens Junction positioning and supermolecular assembly. They also play a role in basal Junction assembly. We test hypotheses for the underlying mechanisms. Our data suggest that the Scribble/Dlg module plays multiple roles in polarity initiation, via Par-1-dependent and independent mechanisms. Different domains of Scribble contribute to these distinct roles. Together these data reveal novel roles for Scribble/Dlg as master scaffolds regulating the assembly of distinct Junctional complexes at different times and places.
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the drosophila afadin and zo 1 homologs canoe and polychaetoid act in parallel to maintain epithelial integrity when challenged by Adherens Junction remodeling
bioRxiv, 2019Co-Authors: Lathiena Manning, Kia Z Perezvale, Kristina N Schaefer, Mycah T Sewell, Mark PeiferAbstract:Abstract During morphogenesis cells must change shape and move without disrupting tissue integrity. This requires cell-cell Junctions to allow dynamic remodeling while resisting force generated by the actomyosin cytoskeleton. Multiple proteins play roles in Junctional-cytoskeletal linkage, but the mechanisms by which they act remain unclear. Drosophila Canoe maintains Adherens Junction-cytoskeletal linkage during gastrulation. Canoe’s mammalian homolog Afadin plays similar roles in cultured cells, working in parallel with ZO-1 proteins, particularly at multicellular Junctions. We took these insights back into the fly embryo, exploring how cells maintain epithelial integrity when challenged by Adherens Junction remodeling during germband extension and dorsal closure. We found Canoe helps cells maintain Junctional-cytoskeletal linkage when challenged by the Junctional remodeling inherent in mitosis, cell intercalation and neuroblast invagination, or by forces generated by the actomyosin cable at the leading edge. However, even in the absence of Canoe many cells retain epithelial integrity. This is explained by a parallel role played by the ZO-1 homolog Polychaetoid. In embryos lacking both Canoe and Polychaetoid, cell Junctions fail early, with multicellular Junctions especially sensitive, leading to widespread loss of epithelial integrity. Our data suggest Canoe and Polychaetoid stabilize Bazooka/Par3 at cell-cell Junctions, helping maintain balanced apical contractility and tissue integrity.
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apkc controls microtubule organization to balance Adherens Junction symmetry and planar polarity during development
Developmental Cell, 2007Co-Authors: Tony J. C. Harris, Mark PeiferAbstract:Tissue morphogenesis requires assembling and disassembling individual cell-cell contacts without losing epithelial integrity. This requires dynamic control of Adherens Junction (AJ) positioning around the apical domain, but the mechanisms involved are unclear. We show that atypical Protein Kinase C (aPKC) is required for symmetric AJ positioning during Drosophila embryogenesis. aPKC is dispensable for initial apical AJ recruitment, but without aPKC, AJs form atypical planar-polarized puncta at gastrulation. Preceding this, microtubules fail to dissociate from centrosomes, and at gastrulation abnormally persistent centrosomal microtubule asters cluster AJs into the puncta. Dynein enrichment at the puncta suggests it may draw AJs and microtubules together and microtubule disruption disperses the puncta. Through cytoskeletal disruption in wild-type embryos, we find a balance of microtubule and actin interactions controls AJ symmetry versus planar polarity during normal gastrulation. aPKC apparently regulates this balance. Without aPKC, abnormally strong microtubule interactions break AJ symmetry and epithelial structure is lost.
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Drosophila p120catenin plays a supporting role in cell adhesion but is not an essential Adherens Junction component.
The Journal of cell biology, 2003Co-Authors: Steven H. Myster, Robert Cavallo, Charles T. Anderson, Donald T. Fox, Mark PeiferAbstract:Cadherin–catenin complexes, localized to Adherens Junctions, are essential for cell–cell adhesion. One means of regulating adhesion is through the juxtamembrane domain of the cadherin cytoplasmic tail. This region is the binding site for p120, leading to the hypothesis that p120 is a key regulator of cell adhesion. p120 has also been suggested to regulate the GTPase Rho and to regulate transcription via its binding partner Kaiso. To test these hypothesized functions, we turned to Drosophila, which has only a single p120 family member. It localizes to Adherens Junctions and binds the juxtamembrane region of DE-cadherin (DE-cad). We generated null alleles of p120 and found that mutants are viable and fertile and have no substantial changes in Junction structure or function. However, p120 mutations strongly enhance mutations in the genes encoding DE-cadherin or Armadillo, the β-catenin homologue. Finally, we examined the localization of p120 during embryogenesis. p120 localizes to Adherens Junctions, but its localization there is less universal than that of core Adherens Junction proteins. Together, these data suggest that p120 is an important positive modulator of adhesion but that it is not an essential core component of Adherens Junctions.