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Apical polarity

Qiuhong Chen, Ritsuko Takada, Chiyo Noda, Satoru Kobayashi, Shinji Takada
Accumulating evidence suggests that exosomes are heterogeneous in molecular composition and physical properties. Here we examined whether epithelial cells secrete a heterogeneous population of exosomes, and if that is the case, whether epithelial cell polarity affects release of different populations of exosomes, especially that of those carrying Wnt. Sucrose-density ultracentrifugation and molecular marker analysis revealed that different populations of exosomes or exosome-like vesicles were released from MDCK cells depending on the cell polarity...
October 21, 2016: Scientific Reports
Xiaopeng Xiong, Xin Li, Yang-An Wen, Tianyan Gao
The proper establishment of epithelial polarity allows cells to sense and respond signals that arise from the microenvironment in a spatiotemporally controlled manner. Atypical PKCs (aPKCs) are implicated as key regulators of epithelial polarity. However, the molecular mechanism underlying the negative regulation of aPKCs remains largely unknown. In this study, we demonstrated that PH domain leucine-rich repeat protein phosphatase (PHLPP), a novel family of Ser/Thr protein phosphatases, plays an important role in regulating epithelial polarity by controlling the phosphorylation of both aPKC isoforms...
October 19, 2016: Journal of Biological Chemistry
Lauren Sfakis, Tim Kamaldinov, Melinda Larsen, James Castracane, Alexander Khmaladze
Quantifying confocal images to enable location of specific proteins of interest in 3D is important for many tissue engineering applications. Quantification of protein localization is essential for evaluation of specific scaffold constructs for cell growth and differentiation for application in tissue engineering and tissue regeneration strategies. Although obtaining information regarding protein expression levels is important, the location of proteins within cells grown on scaffolds is often key to evaluating scaffold efficacy...
October 19, 2016: Tissue Engineering. Part C, Methods
Whitney A Greene, Teresa A Burke, Elaine D Por, Ramesh R Kaini, Heuy-Ching Wang
Purpose: The purpose of this study was to characterize the secretion profile of induced pluripotent stem cell-derived retinal pigment epithelium (iPS-RPE) during wound healing. iPS-RPE was used to develop an in vitro wound healing model. We hypothesized that iPS-RPE secretes cytokines and growth factors which act in an autocrine manner to promote migration and proliferation of cells during wound healing. Methods: iPS-RPE was grown in transwells until fully confluent and pigmented...
August 1, 2016: Investigative Ophthalmology & Visual Science
Joseph Pickering, Matthew Towers
In an influential model of pattern formation, a gradient of Sonic hedgehog (Shh) signalling in the chick wing bud specifies cells with three antero-posterior positional values, which give rise to three morphologically different digits by a self-organizing mechanism with Turing-like properties. However, as four of the five digits of the mouse limb are morphologically similar in terms of phalangeal pattern, it has been suggested that self-organization alone could be sufficient. Here, we show that inhibition of Shh signalling at a specific stage of chick wing development results in a pattern of four digits, three of which can have the same number of phalanges...
October 1, 2016: Development
Weiyue Zheng, Masataka Umitsu, Ishaan Jagan, Charles W Tran, Noboru Ishiyama, Michael BeGora, Kiyomi Araki, Pamela S Ohashi, Mitsuhiko Ikura, Senthil K Muthuswamy
The polarity protein Scribble (SCRIB) regulates apical-basal polarity, directional migration and tumour suppression in Drosophila and mammals. Here we report that SCRIB is an important regulator of myeloid cell functions including bacterial infection and inflammation. SCRIB interacts directly with the NADPH oxidase (NOX) complex in a PSD95/Dlg/ZO-1 (PDZ)-domain-dependent manner and is required for NOX-induced reactive oxygen species (ROS) generation in culture and in vivo. On bacterial infection, SCRIB localized to phagosomes in a leucine-rich repeat-dependent manner and promoted ROS production within phagosomes to kill bacteria...
October 3, 2016: Nature Cell Biology
Roger D Farley
Light and transmission electron microscopy were used to study the development of book lungs in embryos of the spider Parasteatoda tepidariorum. There is a bilateral cluster of temporary lamellae that form just posterior to the second opisthosomal (O2) limb buds. These lamellae are replaced by advanced embryo (AE) book lungs that continue into postembryonic stages. Results herein agree with earlier suggestions that the O2 limb buds become the AE book lungs. Each O2 limb bud merges with the ventral surface of the O2 segment where the limb bud/book lung is internalized by covering with epidermis...
September 28, 2016: Arthropod Structure & Development
Francisco J Calero-Cuenca, Sol Sotillos
A tight relationship between apico-basal polarity and trafficking is essential for epithelial physiology and tissue homeostasis. Recent studies have described how some Rab GTPases, key components of the intracellular traffic machinery, contribute to the establishment of cell polarity in vertebrates. We have demonstrated a novel connection between cell polarity and trafficking: in Drosophila epithelia, the apical determinant aPKC is recycled via Rab11-Nuf-recycling endosomes to maintain cell polarity. Furthermore, the phosphorylation of Nuf by aPKC allows aPKC to control the sub-cellular localization of Nuf and its own membrane accumulation...
September 29, 2016: Small GTPases
Valérie Wattelet-Boyer, Lysiane Brocard, Kristoffer Jonsson, Nicolas Esnay, Jérôme Joubès, Frédéric Domergue, Sébastien Mongrand, Natasha Raikhel, Rishikesh P Bhalerao, Patrick Moreau, Yohann Boutté
The post-Golgi compartment trans-Golgi Network (TGN) is a central hub divided into multiple subdomains hosting distinct trafficking pathways, including polar delivery to apical membrane. Lipids such as sphingolipids and sterols have been implicated in polar trafficking from the TGN but the underlying mechanisms linking lipid composition to functional polar sorting at TGN subdomains remain unknown. Here we demonstrate that sphingolipids with α-hydroxylated acyl-chains of at least 24 carbon atoms are enriched in secretory vesicle subdomains of the TGN and are critical for de novo polar secretory sorting of the auxin carrier PIN2 to apical membrane of Arabidopsis root epithelial cells...
2016: Nature Communications
Thérèse Sergent, Karine Croizet, Yves-Jacques Schneider
SCOPE: Silicon is one of the most abundant trace elements in the body. Although pharmacokinetics data described its absorption from the diet and its body excretion, the mechanisms involved in the uptake and transport of silicon across the gut wall have not been established. METHODS AND RESULTS: Caco-2 cells were used as a well-accepted in vitro model of the human intestinal epithelium to investigate the transport, across the intestinal barrier in both the absorption and excretion directions, of silicon supplied as orthosilicic acid stabilized by vanillin (OSA-VC)...
September 27, 2016: Molecular Nutrition & Food Research
Basile Tarchini, Abigail L D Tadenev, Nicholas Devanney, Michel Cayouette
Sensory perception in the inner ear relies on the hair bundle, the highly polarized brush of movement detectors crowning hair cells. We previously showed that, in the mouse cochlea, the edge of the forming bundle is defined by the 'bare zone', a microvilli-free sub-region of apical membrane specified by the mInsc-LGN-Gαi protein complex. We now report that LGN and Gαi also occupy the very tip of stereocilia that directly abut the bare zone. We demonstrate that LGN and Gαi are both essential to promote the elongation and differential identity of stereocilia across rows...
September 22, 2016: Development
Maroof Alam, Audrey Bouillez, Ashujit Tagde, Rehan Ahmad, Hasan Rajabi, Takahiro Maeda, Masayuki Hiraki, Yozo Suzuki, Donald Kufe
: Apical-basal polarity and epithelial integrity are maintained in part by the Crumbs (CRB) complex. The C-terminal subunit of MUC1 (MUC1-C) is a transmembrane protein that is expressed at the apical border of normal epithelial cells and aberrantly at high levels over the entire surface of their transformed counterparts. However, it is not known if MUC1-C contributes to this loss of polarity that is characteristic of carcinoma cells. Here it is demonstrated that MUC1-C downregulates expression of the Crumbs complex CRB3 protein in triple-negative breast cancer (TNBC) cells...
September 22, 2016: Molecular Cancer Research: MCR
Emily H Stoops, Michael Hull, Michael J Caplan
Polarized epithelial cells sort newly synthesized and recycling plasma membrane proteins into distinct trafficking pathways directed to either the apical or basolateral membrane domains. While the trans Golgi network is a well-established site of protein sorting, increasing evidence indicates a key role for endosomes in the initial trafficking of newly synthesized proteins. Both basolateral and apical proteins have been shown to traverse endosomes en route to the plasma membrane. In particular, apical proteins traffic through either subapical early or recycling endosomes...
September 20, 2016: Traffic
Diego Cevallos Porta, Susana López, Carlos F Arias, Pavel Isa
Rotaviruses infect mature enterocytes from small intestine, however most data about their cellular entry are from studies carried out in non-intestinal polarized or non-polarized cell lines. In this work the entry of porcine rotavirus YM strain into small intestinal cell line IPEC-J2 was studied. It was found that YM and the human rotavirus Wa strain infect preferentially from the basolateral cell surface. Cell infection from the apical and basolateral surfaces was dependent on the presence of cholesterol. The treatment with neuraminidase, sucrose, and bafilomycin suggests that there are differences in the receptor usage and entry mechanism of the virus from the apical and basolateral surface...
September 15, 2016: Virology
Ying Gao, C Yan Cheng
Cell polarity is crucial to development since apico-basal polarity conferred by the 3 polarity protein modules (or complexes) is essential during embryogenesis, namely the Par (partition defective)-, the CRB (Crumbs)-, and the Scribble-based polarity protein modules. While these protein complexes and their component proteins have been extensively studied in Drosophila and C. elegans and also other mammalian tissues and/or cells, their presence and physiological significance in the testis remain unexplored until the first paper on the Par-based protein published in 2008...
May 2016: Spermatogenesis
Romina Fiorotto, Ambra Villani, Antonis Kourtidis, Roberto Scirpo, Mariangela Amenduni, Peter J Geibel, Massimilano Cadamuro, Carlo Spirli, Panos Z Anastasiadis, Mario Strazzabosco
: In the liver, CFTR regulates bile secretion and other functions at the apical membrane of biliary epithelial cells (i.e cholangiocytes). CF-related liver disease (CFLD) is a major cause of death in patients with CF. CFTR dysfunction affects innate immune pathways, generating a para-inflammatory status in the liver, and other epithelia. This study investigates the mechanisms linking CFTR to TLR4 activity. We found that CFTR is associated in a multi-protein complex at the apical membrane of normal mouse cholangiocytes, with proteins that negatively control Src activity...
September 15, 2016: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
Benoit Aigouy, André Le Bivic
The localisation of apico-basal polarity proteins along the Z-axis of epithelial cells is well understood while their distribution in the plane of the epithelium is poorly characterised. Here we provide a systematic description of the planar localisation of apico-basal polarity proteins in the Drosophila ommatidial epithelium. We show that the adherens junction proteins Shotgun and Armadillo, as well as the baso-lateral complexes, are bilateral, i.e. present on both sides of cell interfaces. In contrast, we report that other key adherens junction proteins, Bazooka and the myosin regulatory light chain (Spaghetti squash) are unilateral, i...
2016: Scientific Reports
Chiraz Yemmen, Yann Quilichini, Bernard Marchand, Sihem Bahri
Ultrastructural description of Ceratomyxa aegyptiaca Yemmen, Marton, Eszterbauer and Bahri, 2012 infecting the gallbladder of Solea aegyptiaca Chabanaud, 1927 from a tunisian north-east costal lagoon, was presented in this study. The primary cell was attached to the gallbladder epithelium and presented at one side cytoplasmic projections corresponding to pinocytotic invaginations. Netherless, early sporogonic stages development was carried with contact to the epithelial cells of gallbladder. Immature spores were identified in early sporoblasts by their valvogenic, capsulogenic and binucleated sporoplasmic cells...
2016: Zootaxa
Mika Toya, Masatoshi Takeichi
Polarized epithelial cells contain a characteristic array of microtubules in which non-centrosomal microtubules are aligned along the apical-to-basal axis of the cell with their minus ends oriented towards the apical pole. Although this unique orientation of microtubules was discovered in the late 1980s, how this orientation is established remains unresolved partly because of limited information about molecular factors that regulate the minus ends of non-centrosomal microtubules. Recent studies, however, identified novel minus end-associated proteins, revealing mechanisms by which the polarized arrays of microtubules are established in epithelial cells...
September 8, 2016: Cell Structure and Function
Marta Grabiec, Hana Hříbková, Miroslav Vařecha, Dana Střítecká, Aleš Hampl, Petr Dvořák, Yuh-Man Sun
This study elucidated the stage-specific roles of FGF2 signaling during neural development using in-vitro human embryonic stem cell-based developmental modeling. We found that the dysregulation of FGF2 signaling prior to the onset of neural induction resulted in the malformation of neural rosettes (a neural tube-like structure), despite cells having undergone neural induction. The aberrant neural rosette formation may be attributed to the misplacement of ZO-1, which is a polarized tight junction protein and shown co-localized with FGF2/FGFR1 in the apical region of neural rosettes, subsequently led to abnormal neurogenesis...
August 27, 2016: Stem Cell Research
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