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Flagellar Locomotion in E. coli
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In an ever-changing environment, it is essential that organisms are able to sense these changes and to respond appropriately. Possible responses include alterations in gene expression and/or active movement towards or away from an environment. Most sensory pathways in eukaryotic organisms rely on serine, threonine or tyrosine protein kinases, whereas [...]
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FLT3 Signaling
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FLT3 (Fms-like Tyrosine Kinase-3), also known as FLK2 (Fetal Liver Kinase-2) and STK1 (human Stem Cell Kinase-1) was originally isolated as a hematopoietic progenitor cell-specific kinase, and belongs to the Class-III RTK (Receptor Tyrosine Kinase) family to which c-Fms, c-Kit, and the PDGFR (Platelet Derived Growth Factor Receptor) also belong [...]
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fMLP Pathway
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Neutrophils play an important role in the host defense by invading microbial pathogens. Upon infection neutrophils become activated through interaction with chemo attractants and cytokines. These ligands bind to a variety of cell surface receptors, including heterotrimeric GPCR (G-Protein Coupled Receptors) for fMLP (N-formyl-Met-Leu-Phe) and PAF (Platelet Activating Factor), and [...]
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Frizzled-PCP Pathway in D. melanogaster
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In multicellular organisms, epithelia form highly organized structures. Epithelial apical-basolateral polarity enables the tissues to perform functions such as vectorial transport of fluid or secretion of specialized components to either their apical or basal side. However, the function of some tissues requires an additional axis of polarity within an epithelium, [...]
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G-AlphaI Signaling
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The heterotrimeric G-Proteins (Guanine nucleotide-binding Proteins) are signal transducers that communicate signals from many hormones, neurotransmitters, chemokines, and autocrine and paracrine factors. The extracellular signals are received by members of a large superfamily of receptors with seven membrane-spanning regions, known as GPCR (G-Protein Coupled Receptor), that activate the G-proteins, which [...]
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G-AlphaQ Signaling
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GPCR (G-Protein-Coupled Receptors) constitute a large and diverse family of proteins whose primary function is to transduce extracellular stimuli into intracellular signals. They are among the largest and most diverse protein families in mammalian genomes. Also termed Serpentine receptors, GPCRs are polytopic membrane proteins that share a common structure with [...]
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G-AlphaS Signaling
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G-proteins are heterotrimers, consisting of Alpha, Beta and Gamma subunits, and are involved in signaling to distinct effectors. Heterotrimeric G-proteins convey extracellular signals that activate 7-transmembrane-spanning GPCRs (G-Protein-Coupled Receptors) to the inside of cells, communicating this information to effector proteins and thus initiating changes in cell behaviour. GPCRs constitute a [...]
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G-Beta Gamma Signaling
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G-proteins (Guanine Nucleotide-Binding Proteins) are heterotrimeric proteins that mediate signal transduction between many membrane-bound receptors and intracellular effectors. Traditionally, activation of heterotrimeric G-proteins is accomplished exclusively by the action of GPCRs (G-Protein Coupled Receptors), Seven transmembrane-spanning proteins that typically reside in the Plasma membrane. G-proteins consist of Alpha, Beta and [...]
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G-Protein Signaling through Tubby Protein
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The Tubby protein is the founding member of a multigene protein family that plays an important role in maintenance and function of neuronal cells during development and post-differentiation. Currently, four Tubby gene family members (TUB, TULP1, TULP2 and TULP3) have been identified, which are conserved among different species of mammals [...]
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G1-S Phase Transition
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Cell cycle arrest in response to DNA damage is an important mechanism for
maintaining genomic integrity. This cell cycle arrest provides time for DNA
repair to prevent replication or segregation of damaged DNA. Induction of growth
arrest by DNA damage occurs mainly through the activation of checkpoint pathways
that delay [...]
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G12-G13 in Cellular Signaling
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The G12 subfamily of heterotrimeric G proteins, comprised of the Alpha-subunits G-Alpha12 and G-Alpha13, has been implicated as a signaling component in cellular processes ranging from cytoskeletal changes to cell growth and oncogenesis. Activated G-Alpha12 and G-Alpha13 have a molecular weight of 43,000 kDa and they show more than 66% [...]
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G2-M Phase Transition
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The cellular responses to DNA damage induced by ionizing radiation include activation of cell cycle checkpoints that delay progression of cells through the cell cycle. Ionizing radiation-induced checkpoints are active at the transition from the G1-phase to the S-phase, in the S-phase, and at the transition from the G2-phase to [...]
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GADD45 Pathway
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Genotoxic stress is an important and ubiquitous type of stress that cells are inevitably exposed to over the life span of an organism. Many potentially damaging agents both from the environment and from endogenous processes involving activated oxygen species and other reactive agents can damage the DNA in cells (Ref.1). [...]
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GDNF-Family Ligands and Receptor Interactions
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Neurotrophic factors are a broad set of peptide growth factors that tightly regulate many critical aspects of the ontogeny of neurons, such as the number of neurons in a given population, neurite branching and synaptogenesis, adult synaptic plasticity and maturation of electrophysiological properties. Neurotrophic factors include Neurotrophins, Neurokines and GDNF (Glial-cell-line-derived Neurotrophic [...]
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Germ Cell-Sertoli Cell Junction Dynamics
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Sertoli-Germ (Spermatid)-cell interactions affect spermatogenesis at the molecular, cellular and biochemical levels. Germ cell movement within the epithelium is vital because germ cells, if induced to release into the tubule lumen prematurely, will be unable to fertilize the ovum. On the other hand, if germ cells are forced to remain [...]
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GHRH Signaling
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GHRH (Growth Hormone-Releasing Hormone) is a hypothalamic hormone that is essential for normal expansion of the somatotrope lineage during pituitary development. GHRH is produced by GHRH cells in the hypothalamus and reaches the adenohypophysis via the portal system. It stimulates the release of GH (Growth Hormone)/Somatotropin from the adenohypophysis. GH [...]
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Gibberellin Signaling in Barley Aleurone Grain
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GAs (Gibberellins) are members of a large family of Diterpenoid compounds, which are essential for a number of processes, including Gene Expression in Cereal Aleurones, Seed Germination, Elongation, Growth, and Flowering. During the last four decades, Barley Aleurone has been a valuable system for studying GA regulation of gene expression. [...]
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GITR Pathway
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GITR (Glucocorticoid-Induced TNFR Family-Related) also termed AITR (Activation-Inducible TNFR Family Receptor) is a member of the TNFRSF18 (TNF Receptor Superfamily 18). It is a 228-amino acids type I transmembrane protein that is suggested to be a close relative of 4-1BB and CD27. Inducible during T-Cell activation, the molecule has a [...]
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Glioblastoma Multiforme
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Glioblastoma Multiforme (GBM) is biologically aggressive neoplasms which have an elevated, often aberrant, proliferative capacity with a diffuse pattern of brain invasion. It is the most malignant Astrocytic tumor, composed of poorly differentiated neoplastic astrocytes (Ref.1). The World Health Organization (WHO) grading system classifies Gliomas into Grades I-IV based on [...]
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Glioma Invasiveness
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Gliomas are the most common intracranial malignant tumors in humans, and high-grade Gliomas in particular pose a unique challenge due to their propensity for proliferation and tissue invasion (Ref.1). The invasion of neoplastic cells into healthy brain tissue is a pathologic hallmark of Gliomas and contributes to the failure of [...]
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