Arabinogalactan Proteins in Plant Roots – An Update on Possible Functions

Responsiveness to environmental conditions and developmental plasticity of root systems are crucial determinants of plant fitness. These processes are interconnected at a cellular level with cell wall properties and cell surface signaling, which involve arabinogalactan proteins (AGPs) as essential components. AGPs are cell-wall localized glycoproteins, often GPI-anchored, which participate in root functions at many levels. They are involved in cell expansion and differentiation, regulation of root growth, interactions with other organisms, and environmental response. Due to the complexity of cell wall functional and regulatory networks, and despite the large amount of experimental data, the exact molecular mechanisms of AGP-action are still largely unknown. This dynamically evolving field of root biology is summarized in the present review.

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N-Acetylglucosamine Functions in Cell Signaling

Scientifica ◽

10.6064/2012/489208 ◽

2012 ◽

Vol 2012 ◽

pp. 1-15 ◽

Cited By ~ 63

Author(s):

James B. Konopka

Keyword(s):

Cell Wall ◽

Cell Surface ◽

Cell Signaling ◽

Amino Sugar ◽

Animal Cells ◽

Fungal Cell ◽

E Coli ◽

Human Fungal Pathogen ◽

Surface Signaling ◽

Cell Surface Signaling

The amino sugar N-acetylglucosamine (GlcNAc) is well known for the important structural roles that it plays at the cell surface. It is a key component of bacterial cell wall peptidoglycan, fungal cell wall chitin, and the extracellular matrix of animal cells. Interestingly, recent studies have also identified new roles for GlcNAc in cell signaling. For example, GlcNAc stimulates the human fungal pathogenCandida albicansto undergo changes in morphogenesis and expression of virulence genes. PathogenicE. coliresponds to GlcNAc by altering the expression of fimbriae and CURLI fibers that promote biofilm formation and GlcNAc stimulates soil bacteria to undergo changes in morphogenesis and production of antibiotics. Studies with animal cells have revealed that GlcNAc influences cell signaling through the posttranslational modification of proteins by glycosylation. O-linked attachment of GlcNAc to Ser and Thr residues regulates a variety of intracellular proteins, including transcription factors such as NFκB, c-myc, and p53. In addition, the specificity of Notch family receptors for different ligands is altered by GlcNAc attachment to fucose residues in the extracellular domain. GlcNAc also impacts signal transduction by altering the degree of branching of N-linked glycans, which influences cell surface signaling proteins. These emerging roles of GlcNAc as an activator and mediator of cellular signaling in fungi, animals, and bacteria will be the focus of this paper.

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Cell Wall Chitosaccharides Are Essential Components and Exposed Patterns of the Phytopathogenic Oomycete Aphanomyces euteiches

Eukaryotic Cell ◽

10.1128/ec.00091-08 ◽

2008 ◽

Vol 7 (11) ◽

pp. 1980-1993 ◽

Cited By ~ 51

Author(s):

Ilham Badreddine ◽

Claude Lafitte ◽

Laurent Heux ◽

Nicholas Skandalis ◽

Zacharoula Spanou ◽

...

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Molecular Mechanisms ◽

Expressed Sequence Tag ◽

Pathogenic Fungi ◽

Aphanomyces Euteiches ◽

Fungal Cell ◽

Cdna Sequences ◽

Essential Components ◽

Biochemical Analyses

ABSTRACT Chitin is an essential component of fungal cell walls, where it forms a crystalline scaffold, and chitooligosaccharides derived from it are signaling molecules recognized by the hosts of pathogenic fungi. Oomycetes are cellulosic fungus-like microorganisms which most often lack chitin in their cell walls. Here we present the first study of the cell wall of the oomycete Aphanomyces euteiches, a major parasite of legume plants. Biochemical analyses demonstrated the presence of ca. 10% N-acetyl-d-glucosamine (GlcNAc) in the cell wall. Further characterization of the GlcNAc-containing material revealed that it corresponds to noncrystalline chitosaccharides associated with glucans, rather than to chitin per se. Two putative chitin synthase (CHS) genes were identified by data mining of an A. euteiches expressed sequence tag collection and Southern blot analysis, and full-length cDNA sequences of both genes were obtained. Phylogeny analysis indicated that oomycete CHS diversification occurred before the divergence of the major oomycete lineages. Remarkably, lectin labeling showed that the Aphanomyces euteiches chitosaccharides are exposed at the cell wall surface, and study of the effect of the CHS inhibitor nikkomycin Z demonstrated that they are involved in cell wall function. These data open new perspectives for the development of antioomycete drugs and further studies of the molecular mechanisms involved in the recognition of pathogenic oomycetes by the host plants.

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Influence of environmental temperature on mouth-form plasticity in Pristionchus pacificus acts through daf-11-dependent cGMP signaling

10.1101/2021.05.22.445254 ◽

2021 ◽

Author(s):

Masa Lenuzzi ◽

Hanh Witte ◽

Metta Riebesell ◽

Christian Roedelsperger ◽

Ray L. Hong ◽

...

Keyword(s):

Regulatory Networks ◽

Developmental Plasticity ◽

Molecular Mechanisms ◽

Environmental Temperature ◽

Elevated Temperatures ◽

Environmental Sensing ◽

Environmental Signals ◽

Pristionchus Pacificus ◽

Cgmp Signaling ◽

Developmental Switch

Mouth-form plasticity in the nematode Pristionchus pacificus has become a powerful system to identify the genetic and molecular mechanisms associated with phenotypic (developmental) plasticity. In particular, the identification of developmental switch genes that can sense environmental stimuli and reprogram developmental processes has confirmed long-standing evolutionary theory. Together with the associated gene regulatory networks, these developmental switch genes have been important to show that plasticity is consistent with the Modern Synthesis of evolution. However, how these genes are involved in the direct sensing of the environment, or if the switch genes act downstream of another, primary environmental sensing mechanism, remains currently unknown. Here, we study the influence of environmental temperature on mouth-form plasticity. Using forward and reverse genetic technology including CRISPR/Cas9, we show that mutations in the guanylyl cyclase Ppa-daf-11, the Ppa-daf-25/AnkMy2 and the cyclic nucleotide-gated channel Ppa-tax-2 eliminate the response to elevated temperatures. Together, our study indicates that DAF-11, DAF-25 and TAX-2 have been co-opted for environmental sensing during mouth-form plasticity regulation in P. pacificus. This work suggests that developmental switch genes integrate environmental signals including perception by cGMP signaling.

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An Insight into GPCR and G-Proteins as Cancer Drivers

Cells ◽

10.3390/cells10123288 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3288

Author(s):

Preeti Kumari Chaudhary ◽

Soochong Kim

Keyword(s):

Tumor Growth ◽

G Proteins ◽

Cancer Progression ◽

Molecular Mechanisms ◽

Surface Signaling ◽

Tumor Growth And Metastasis ◽

Signaling Receptors ◽

Cell Surface Signaling ◽

Multiple Signaling ◽

Insight Into

G-protein-coupled receptors (GPCRs) are the largest family of cell surface signaling receptors known to play a crucial role in various physiological functions, including tumor growth and metastasis. Various molecules such as hormones, lipids, peptides, and neurotransmitters activate GPCRs that enable the coupling of these receptors to highly specialized transducer proteins, called G-proteins, and initiate multiple signaling pathways. Integration of these intricate networks of signaling cascades leads to numerous biochemical responses involved in diverse pathophysiological activities, including cancer development. While several studies indicate the role of GPCRs in controlling various aspects of cancer progression such as tumor growth, invasion, migration, survival, and metastasis through its aberrant overexpression, mutations, or increased release of agonists, the explicit mechanisms of the involvement of GPCRs in cancer progression is still puzzling. This review provides an insight into the various responses mediated by GPCRs in the development of cancers, the molecular mechanisms involved and the novel pharmacological approaches currently preferred for the treatment of cancer. Thus, these findings extend the knowledge of GPCRs in cancer cells and help in the identification of therapeutics for cancer patients.

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Histological aspects of the cryopreservation of potato

Acta Agronomica Hungarica ◽

10.1556/aagr.56.2008.3.10 ◽

2008 ◽

Vol 56 (3) ◽

pp. 341-348

Author(s):

P. Pepó ◽

A. Kovács

Keyword(s):

Cell Wall ◽

Low Temperatures ◽

Cell Walls ◽

Cellular Level ◽

Adaptive Mechanism ◽

Epidermal Layer ◽

Freezing And Thawing ◽

Meristematic Cells ◽

Suitable Solution ◽

Vacuolated Cells

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

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Radio-Susceptibility of Nasopharyngeal Carcinoma: Focus on Epstein- Barr Virus, MicroRNAs, Long Non-Coding RNAs and Circular RNAs

Current Molecular Pharmacology ◽

10.2174/1874467213666191227104646 ◽

2020 ◽

Vol 13 (3) ◽

pp. 192-205 ◽

Cited By ~ 2

Author(s):

Fanghong Lei ◽

Tongda Lei ◽

Yun Huang ◽

Mingxiu Yang ◽

Mingchu Liao ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Regulatory Networks ◽

Epstein Barr Virus ◽

Molecular Mechanisms ◽

Acquired Resistance ◽

Treatment Strategies ◽

Circular Rnas ◽

Barr Virus ◽

Non Coding Rnas ◽

Epstein Barr

Nasopharyngeal carcinoma (NPC) is a type of head and neck cancer. As a neoplastic disorder, NPC is a highly malignant squamous cell carcinoma that is derived from the nasopharyngeal epithelium. NPC is radiosensitive; radiotherapy or radiotherapy combining with chemotherapy are the main treatment strategies. However, both modalities are usually accompanied by complications and acquired resistance to radiotherapy is a significant impediment to effective NPC therapy. Therefore, there is an urgent need to discover effective radio-sensitization and radio-resistance biomarkers for NPC. Recent studies have shown that Epstein-Barr virus (EBV)-encoded products, microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), which share several common signaling pathways, can function in radio-related NPC cells or tissues. Understanding these interconnected regulatory networks will reveal the details of NPC radiation sensitivity and resistance. In this review, we discuss and summarize the specific molecular mechanisms of NPC radio-sensitization and radio-resistance, focusing on EBV-encoded products, miRNAs, lncRNAs and circRNAs. This will provide a foundation for the discovery of more accurate, effective and specific markers related to NPC radiotherapy. EBVencoded products, miRNAs, lncRNAs and circRNAs have emerged as crucial molecules mediating the radio-susceptibility of NPC. This understanding will improve the clinical application of markers and inform the development of novel therapeutics for NPC.

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Claudin Tight Junction Proteins: Novel Aspects in Paracellular Transport

Peritoneal Dialysis International ◽

10.1177/089686080802800605 ◽

2008 ◽

Vol 28 (6) ◽

pp. 577-584 ◽

Cited By ~ 32

Author(s):

Constanze Will ◽

Michael Fromm ◽

Dominik Müller

Keyword(s):

Tight Junction ◽

Solute Transport ◽

Molecular Mechanisms ◽

Family Members ◽

Transport Processes ◽

Paracellular Transport ◽

Solute Flux ◽

Solute Fluxes ◽

Essential Components ◽

Renal Tubular

Claudins are essential components of the intercellular tight junction and major determinants of paracellular solute fluxes across epithelia and endothelia. Many members of this family display a distinct charge or size specificity, whereas others render the epithelium impermeable to transport. Due to intercellular localization, claudin-mediated transport processes are passive and driven by an electrochemical gradient. In epithelial tissues, claudins exhibit a temporal–spatial expression pattern corresponding with regional and local solute transport profiles. Whereas paracellular transport mechanisms in organs such as intestine and kidney have been extensively investigated, little is known about the molecular mechanisms determining solute transport in the peritoneum, and thus the determinants of peritoneal dialysis. Given the ubiquitous expression of claudins in endothelia and epithelia, it is predictable that claudins also contribute to pore formation and determination in the peritoneum, and that they are involved in solute flux. Therefore, we review the basic characteristics of claudin family members and their function as exemplified in renal tubular transport and give an outlook to what extent claudin family members might be of importance for solute reabsorption across the peritoneal membrane.

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Integrative Modelling of Gene Expression and Digital Phenotypes to Describe Senescence in Wheat

Genes ◽

10.3390/genes12060909 ◽

2021 ◽

Vol 12 (6) ◽

pp. 909

Author(s):

Anyela Valentina Camargo Rodriguez

Keyword(s):

Gene Expression ◽

Regulatory Networks ◽

Molecular Mechanisms ◽

Developmental Stages ◽

Computational Modelling ◽

Plant Morphology ◽

Reproductive Organs ◽

Biological Trait ◽

Cereal Grain ◽

Plant Level

Senescence is the final stage of leaf development and is critical for plants’ fitness as nutrient relocation from leaves to reproductive organs takes place. Although senescence is key in nutrient relocation and yield determination in cereal grain production, there is limited understanding of the genetic and molecular mechanisms that control it in major staple crops such as wheat. Senescence is a highly orchestrated continuum of interacting pathways throughout the lifecycle of a plant. Levels of gene expression, morphogenesis, and phenotypic development all play key roles. Yet, most studies focus on a short window immediately after anthesis. This approach clearly leaves out key components controlling the activation, development, and modulation of the senescence pathway before anthesis, as well as during the later developmental stages, during which grain development continues. Here, a computational multiscale modelling approach integrates multi-omics developmental data to attempt to simulate senescence at the molecular and plant level. To recreate the senescence process in wheat, core principles were borrowed from Arabidopsis Thaliana, a more widely researched plant model. The resulted model describes temporal gene regulatory networks and their effect on plant morphology leading to senescence. Digital phenotypes generated from images using a phenomics platform were used to capture the dynamics of plant development. This work provides the basis for the application of computational modelling to advance understanding of the complex biological trait senescence. This supports the development of a predictive framework enabling its prediction in changing or extreme environmental conditions, with a view to targeted selection for optimal lifecycle duration for improving resilience to climate change.

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Galectin-3: A factotum in carcinogenesis bestowing an archery for prevention

Tumor Biology ◽

10.3233/tub-200051 ◽

2021 ◽

Vol 43 (1) ◽

pp. 77-96

Author(s):

T. Jeethy Ram ◽

Asha Lekshmi ◽

Thara Somanathan ◽

K. Sujathan

Keyword(s):

Cancer Progression ◽

Molecular Mechanisms ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Therapy Resistance ◽

Cellular Level ◽

Clinical Samples ◽

Innovative Strategy ◽

Mesenchymal Transition ◽

Galectin 3

Cancer metastasis and therapy resistance are the foremost hurdles in oncology at the moment. This review aims to pinpoint the functional aspects of a unique multifaceted glycosylated molecule in both intracellular and extracellular compartments of a cell namely galectin-3 along with its metastatic potential in different types of cancer. All materials reviewed here were collected through the search engines PubMed, Scopus, and Google scholar. Among the 15 galectins identified, the chimeric gal-3 plays an indispensable role in the differentiation, transformation, and multi-step process of tumor metastasis. It has been implicated in the molecular mechanisms that allow the cancer cells to survive in the intravascular milieu and promote tumor cell extravasation, ultimately leading to metastasis. Gal-3 has also been found to have a pivotal role in immune surveillance and pro-angiogenesis and several studies have pointed out the importance of gal-3 in establishing a resistant phenotype, particularly through the epithelial-mesenchymal transition process. Additionally, some recent findings suggest the use of gal-3 inhibitors in overcoming therapeutic resistance. All these reports suggest that the deregulation of these specific lectins at the cellular level could inhibit cancer progression and metastasis. A more systematic study of glycosylation in clinical samples along with the development of selective gal-3 antagonists inhibiting the activity of these molecules at the cellular level offers an innovative strategy for primary cancer prevention.

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Somatic Embryogenesis in Centaurium erythraea Rafn—Current Status and Perspectives: A Review

Plants ◽

10.3390/plants10010070 ◽

2020 ◽

Vol 10 (1) ◽

pp. 70

Author(s):

Ana D. Simonović ◽

Milana M. Trifunović-Momčilov ◽

Biljana K. Filipović ◽

Marija P. Marković ◽

Milica D. Bogdanović ◽

...

Keyword(s):

Somatic Embryogenesis ◽

Somatic Embryos ◽

Developmental Plasticity ◽

Leaf Explants ◽

Arabinogalactan Proteins ◽

Culture Conditions ◽

Current Status ◽

Special Focus ◽

Root Explants ◽

Centaurium Erythraea

Centaurium erythraea (centaury) is a traditionally used medicinal plant, with a spectrum of secondary metabolites with confirmed healing properties. Centaury is an emerging model in plant developmental biology due to its vigorous regenerative potential and great developmental plasticity when cultured in vitro. Hereby, we review nearly two decades of research on somatic embryogenesis (SE) in centaury. During SE, somatic cells are induced by suitable culture conditions to express their totipotency, acquire embryogenic characteristics, and eventually give rise to somatic embryos. When SE is initiated from centaury root explants, the process occurs spontaneously (on hormone-free medium), directly (without the callusing phase), and the somatic embryos are of unicellular origin. SE from leaf explants has to be induced by plant growth regulators and is indirect (preceded by callusing). Histological observations and culture conditions are compared in these two systems. The changes in antioxidative enzymes were followed during SE from the leaf explants. Special focus is given to the role of arabinogalactan proteins during SE, which were analyzed using a variety of approaches. The newest and preliminary results, including centaury transcriptome, novel potential SE markers, and novel types of arabinogalactan proteins, are discussed as perspectives of centaury research.

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