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Signal Transduction related Pathways

Akt Signaling [ Details | Top ]
Akt (v-Akt Murine Thymoma Viral Oncogene)/ PKB (Protein Kinase-B) is a Serine/threonine Kinase that is involved in mediating various biological responses, such as inhibition of Apoptosis and stimulation of cell proliferation. Three mammalian isoforms are currently known: Akt1/PKB- Alpha, Akt2/PKB-Beta and Akt3/PKB-Gamma. All three isoforms of Akt share a common structure of three domains. The N-terminus of the protein is a PH (Pleckstrin Homology) domain, which interacts with membrane lipid products such as PIP2 (Phosphatidylinositol-3,4-Bisphosphate) and PIP3 (Phosphatidylinositol-3,4,5-Triphosphate)....

cAMP Pathway [ Details | Top ]
cAMP (Cyclic Adenosine 3',5'-monophosphate) is the first identified second messenger, which has a fundamental role in the cellular response to many extracellular stimuli. The cAMP signaling pathway controls a diverse range of cellular processes. Indeed, not only did cAMP provide the paradigm for the second messenger concept, but also provided the paradigm for signaling compartmentalization. The different receptors, chiefly the GPCRs (G-Protein Coupled Receptors), Alpha and Beta-ADRs (Adrenergic Receptors), Growth Factor receptors, CRHR (Corticotropin Releasing Hormone Receptor), GcgR (Glucagon Receptor), DCC...

Caspase Cascade [ Details | Top ]
Caspases are a family of cysteine proteases that act in concert in a cascade triggered by apoptosis signaling. The culmination of this cascade is the cleavage of a number of proteins in the cell, followed by cell disassembly, cell death, and, ultimately, the phagocytosis and removal of the cell debris. The Caspase cascade is activated by two distinct routes: one from cell surface and the other from mitochondria (Ref.1). The pathway leading to Caspase activation varies according to the apoptotic stimulus. Initiator Caspases (including 8, 9, 10 and 12) are closely coupled to pro-apototic signals. Pro-apoptotic stimuli include the FasL (Fas Ligand), TNF...

CD40 Signaling - New [ Details | Top ]
CD40, a TNFR (Tumor Necrosis Factor Receptor) family member, conveys signals regulating diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death. First identified and functionally characterized on B-Cells, CD40 is expressed on a plethora of different cell types, including B-Cells, macrophages, dendritic cells, endothelial cells, and fibroblasts, and this widespread expression accounts for the central role of CD40 in the regulation of immune response and host defense (Ref.1). Binding of CD40 with its counter receptor, CD154 (also termed CD40L [CD40 ligand] or GP39), act...

Cellular Apoptosis Pathway [ Details | Top ]
Apoptosis is a naturally occurring process by which a cell is directed to Programmed Cell Death. Apoptosis is based on a genetic program that is an indispensable part of the development and function of an organism. In this process, cells that are no longer needed or that will be detrimental to an organism or tissue are disposed of in a neat and orderly manner; this prevents the development of an inflammatory response, which is often associated with Necrotic cell death. There are at least two broad pathways that lead to Apoptosis, an "Extrinsic" and an "Intrinsic" Pathway. In both pathways, signaling results in the activation of a family of Cys (Cysteine)...

Chemokine Signaling [ Details | Top ]
Chemokines, or chemotactic cytokines, are a large family of small (6-14 kDa), structurally related proteins that mediate a wide range of biological activities. As a part of normal immune system functions, chemokines are a critical component of basal leukocyte trafficking essential for immune system architecture and development, and immune surveillance. Chemokines also participate in the growth, differentiation, and activation of leukocytes as well as stimulate various effector functions of these cells, such as integrin activation, chemotaxis, superoxide radical production and granule enzyme release. Four classes of chemokines...

CREB Pathway [ Details | Top ]
The process of consolidating a new memory and the dynamic complexity of information processing within neuronal networks is greatly increased by activity-dependent changes in gene expression within individual neurons. A leading paradigm of such regulation is the activation of the nuclear transcription factor CREB (cAMP Responsive Element Binding Protein), and its family members the ATF (Activating Transcription Factor) and CREM (cAMP Response Element Modulator), which belong to bZIP (basic/leucine zipper) class of transcription factors that functions in vivo to regulate the proliferation of pituitary cells and thymocytes...

Cyclins and Cell Cycle Regulation [ Details | Top ]
Progress in the eukaryotic cell cycle is driven by oscillations in the activities of CDKs (Cyclin-Dependent Kinases). CDK activity is controlled by periodic synthesis and degradation of positive regulatory subunits, Cyclins, as well as by fluctuations in levels of negative regulators, by CKIs (CDK Inhibitors), and by reversible phosphorylation. The mammalian cell cycle consists of four discrete phases: S-phase, in which DNA is replicated; M-phase, in which the chromosomes are separated over two new nuclei in the process of mitosis. These two phases are separated by two so called "Gap" phases, G1 and G2...

eNOS Signaling - New [ Details | Top ]
NO (Nitric Oxide) is a short-lived free radical gas involved in diverse physiological and pathological processes. It is produced along with L-Citrulline by the oxidation of L-Arginine and catalyzed by three different isoforms of NOS (NO Synthase). Type-I nNOS (neuronal NOS) and Type-III eNOS (endothelial NOS) are constitutively expressed as latent enzymes and require a higher concentration of Ca2+ for the enzyme activity. In contrast, Type-II iNOS (inducible NOS) is Ca2+ independent because its high affinity for Ca2+/Calm (Calmodulin) renders the enzyme active even at basal levels of intracellular Ca2+ (Ref.1 & 2). The ca...

ERK Signaling [ Details | Top ]
The MAPK (Mitogen-Activated Protein Kinase) pathway is one of the primordial signaling systems that nature has used in several permutations to accomplish an amazing variety of tasks. It exists in all eukaryotes, and controls such fundamental cellular processes as Proliferation, Differentiation, Survival and Apoptosis. Mammalian MAPK can be divided into four groups based on their structure and function: ERKs (Extracellular signal-Regulated Kinases), p38MAPKs, JNKs (c-Jun NH2-terminal Kinases) and ERK5 (Extracellular signal-Regulated Kinase-5) or BMK. Activation of these MAPKs occurs through a cascade of upstream kinases...

Estrogen Pathway [ Details | Top ]
Estrogens play important roles in growth, development, reproduction, and maintenance of a diverse range of mammalian tissues. The physiological effects of estrogens are mediated by the intracellular ERs (Estrogen Receptors), which regulate transcription of target genes through binding to specific DNA target sequences. The ERs orchestrate both transcriptional and non-genomic functions in response to estrogens, xenoestrogens and signals emanating from growth factor signalling pathways. The pleiotropic and tissue-specific effects of estrogens are mediated by the differential expression of two distinct ER subtypes: ER-Alpha and ER-Beta...

FAK1 Signaling - New [ Details | Top ]
Engagement of integrin receptors with extracellular ligands gives rise to the formation of complex multi-protein structures that link the ECM (Extracellular Matrix) to the cytoplasmic actin cytoskeleton and signaling proteins including Talin, Alpha-actinin, Vinculin, Zyxin, Paxillin and FAK (Focal Adhesion Kinase). These adhesive complexes are dynamic, often heterogeneous structures, varying in size and organization, and signaling through these complexes and focal adhesions have been implicated in the regulation of a number of key cellular processes, including growth factor induced mitogenic signals, cell survival, cell pr...

Fas Signaling [ Details | Top ]
Fas (also called Apo1 or CD95) is a death domain-containing member of the TNFR (Tumor Necrosis Factor Receptor) superfamily. It has a central role in the physiological regulation of Programmed Cell Death and has been implicated in the pathogenesis of various malignancies and diseases of the immune system. Although the FasL (Fas Ligand)-Fas system has been appreciated mainly with respect to its death-inducing function, it also transduces proliferative and activating signals through pathways that are still poorly defined. The Fas Receptor induces an apoptotic signal by binding to....

FGF Pathway [ Details | Top ]
Angiogenesis, the growth of new blood vessels, plays a key role in many physiological and pathological processes, such as ovulation, embryogenesis, wound repair, inflammation, malignant tumor growth, retinopathies, rheumatoid arthritis, and angiogenesis-dependent diseases. One of the best-characterized modulators of angiogenesis is the heparin-binding FGF (Fibroblast Growth Factor). FGF induces neovascularization in vivo and is implicated in the growth of new blood vessels during wound healing and embryogenesis. In vitro, FGF induces cell proliferation, migration, and production of proteases in endothelial cells by interacting...

FLT3 Signaling - New [ Details | Top ]
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 (Ref.1). Normal expression of FLT3 is restricted to haemopoietic progenitor cells in the bone marrow, thymus and lymph nodes, but is also found on other tissues such as placenta, brain, cerebellum and gonads. Aberrantly expressed FLT3 is observed at high levels in a spectrum of hema...

Glucocorticoid Receptor Signaling [ Details | Top ]
Our bones get more brittle with increasing age, and to add insult to injury, the most effective therapy for another problem that is associated with getting older, rheumatoid arthritis, often adds to the problem by causing bone resorption. The Glucocorticoid steroids, are the best available anti-inflammatories, and are used widely in the treatment of arthritis, as well as other inflammatory conditions such as dermatitis and autoimmune diseases. The Glucocorticoids, secreted by the Adrenal Cortex are powerful anti-inflammatory compounds due to their ability to inhibit all stages of the inflammatory ...

GPCR Pathway [ Details | Top ]
GPCRs (Guanine Nucleotide Binding–Protein Coupled Receptors) comprise large and diverse gene families in fungi, plants, and the animal kingdom. Also termed serpentine receptors, GPCRs are polytopic membrane proteins that share a common structure with seven transmembrane segments, but sequence similarity is minimal among the most distant GPCRs. Their principal function is to transmit information about the extracellular environment to the interior of the cell, and they do this by interacting with the G-proteins. GPCRs recognize a variety of ligands and stimuli including peptide and non-peptide hormones and neurotransmitters...

GSK 3 Signaling [ Details | Top ]
GSK3 (Glycogen Synthase Kinase-3) is a ubiquitously expressed, highly conserved serine/threonine protein kinase found in all eukaryotes. Identified originally as a regulator of glycogen metabolism, GSK3 acts as a downstream regulatory switch for numerous signaling pathways, including cellular responses to WNT, Growth Factors, Insulin, RTK (Receptor Tyrosine Kinases), Hedgehog pathways, and GPCR (G-Protein-Coupled Receptors) and is involved in a wide range of signal transduction cascades involving cellular processes, ranging from glycogen metabolism, cell development, gene transcription, protein translation to cytoskeletal organization...

Hedgehog - New [ Details | Top ]
Controlled cell proliferation is a predominant theme in normal embryonic and post-embryonic development, and, in many instances, cell-type specification and cell proliferation are intimately coupled. Several secreted intercellular signaling proteins that behave as morphogens during pattern formation are also implicated in the regulation of the cell cycle. Hedgehogs (Hhs) are one such class of morphogens that regulate an enormous variety of developmental events in the fly and vertebrate embryo and plays a central role in several cancers....

HIF1Alpha Pathway [ Details | Top ]
The cellular response to O2 (oxygen) is a central process in animal cells and figures prominently in the pathophysiology of several diseases, including cancer, cardiovascular disease, and stroke. This process is coordinated by the HIF (Hypoxia-Inducible Factor) and its regulator, the pVHL (Von Hippel-Lindau tumor suppressor protein). HIF1 is a basic helix-loop-helix transcription factor that transactivates genes encoding proteins that participate in homeostatic responses to hypoxia. It induces expression of proteins controlling glucose metabolism, cell proliferation, and vascularization. Several genes...

IGF1R Signaling [ Details | Top ]
Programmed cell death, a form of altruistic suicide is a genetically controlled means of cellular self-destruction that leads to dismantling and packaging of cell material for removal by phagocytosis. All cells possess the ability to undergo programmed cell death (otherwise known as apoptosis), and the process is essential for normal development to shape organs and tissues as well as to remove damaged cells. Although the cell may require de novo synthesis of some signaling molecules, the machinery for apoptosis is constantly present and may be rapidly activated. Therefore, the process of apoptosis needs tight regulation...

ILK Signaling - New [ Details | Top ]
The ECM (Extracellular Matrix) provides the structural framework for the formation of tissues and organs. The ECM binds to substrate adhesion molecules on the surface of cells and influences various intracellular signaling pathways that regulate survival, proliferation, polarity and differentiation. The important families of adhesion molecules that bind to the ECM are the Integrins. Integrins consist of Alpha and Beta-subunits and are composed of large extracellular domains and relatively small cytoplasmic domains (Ref.1 & 2). Ligand binding activates signaling cascades that lead to the assembly of a multiprotein complex a...

iNOS Signaling - New [ Details | Top ]
Microorganisms have developed several mechanisms to survive in their hosts' environments. These include competition with their hosts for metal acquisition and resistance to host defenses such as NO (Nitric Oxide), a cytotoxic weapon generated by macrophages. In eukaryotic cells, NO is metabolically produced by NOS (NO Synthase) from L-Arginine, O2 (Molecular Oxygen), and NADPH (Nicotinamide Adenine Dinucleotide, Reduced). In macrophages, an inducible NO synthase (iNOS or NOS2) is produced after activation by endotoxins or cytokines and generates copious amounts of NO presumably to help kill or inhibit the growth of invadin...

Insulin Receptor Pathway [ Details | Top ]
Insulin is the major hormone controlling critical energy functions such as glucose and lipid metabolism. Insulin elicits a diverse array of biological responses by binding to its specific receptor (Ref.1). The insulin receptor belongs to a subfamily of receptor tyrosine kinases that includes the IGF (Insulin-like Growth Factor) receptor and the IRR (Insulin Receptor-Related Receptor). These receptors are tetrameric proteins consisting of two alpha and two beta subunits that function as allosteric enzymes in which the alpha subunit inhibits the tyrosine kinase activity of the beta subunit. Insulin has diverse effects on cells ...

Integrin Signaling Pathway [ Details | Top ]
Adhesive interactions between cells and ECM (Extracellular Matrix) proteins play a vital role in biological processes, including cell survival, growth, differentiation, migration, inflammatory responses, platelet aggregation, tissue repair and tumor invasion (Ref.4) and perturbing this coordination can lead to events such as malignant transformation. The major groups of proteins mediating these interactions are a family of cell surface receptors known as Integrins, named for their role in integrating the intracellular cytoskeleton with the ECM. The signals from these adhesion receptors are integrated with those originating from growth factor receptors...

Interferon Pathway [ Details | Top ]
To thwart viral infection, our cells have developed a formidable and integrated defense network that comprise of innate and adaptive immune responses. In an attempt to prevent viral replication, viral dissemination or persistent viral infection of the cell, many of these protective measures actually involve the induction of programmed cell death, or apoptosis. Once the virus has invaded the cell, a host defense-mediated response is triggered which involves the induction of a family of pleiotropic cytokines known as the IFNs (Interferons) (Ref.1). These IFNs constitute a heterogeneous group of proteins and are best known for their ability to induce...

Intracellular Calcium Signaling - New [ Details | Top ]
Despite tremendous diversities in their expression, cellular activities in virtually all cell types are regulated by common intracellular signaling systems, and calcium is one important ubiquitous intracellular messenger, controlling a diverse range of cellular processes, such as gene transcription, muscle contraction and cell proliferation (Ref.1). In response to adequate stimuli, [Ca2+]i (Intracellular Ca2+ concentration) increases, oscillates and decreases, leading to the activation, modulation and termination of cell function. Numerous channels and pumps allow this particular cation to enter and exit cells and move bet...

IP3 Pathway [ Details | Top ]
IP3 (Inositol 1,4,5-triphosphate), also known as a second messenger, is a molecule that functions to transfer a chemical signal received by the cell, such as from a hormone, neurotransmitters, growth factors and hypertrophic stimuli such as AngII (Angiotensin-II), Beta-adrenergic receptor agonists, and ET1 (Endothelin-1) to various signaling networks within the cell. IP3 is known to play a crucial role in initiating and propagating these messages; however, the precise mechanism of how IP3 relates to the next element in its signaling pathway, the calcium wave, remains highly controversial. The receptors for IP3, IP3R (IP3 Receptor) constitute a family...

JAK/STAT Pathway [ Details | Top ]
Signaling pathways mediating the transduction of information between cells are essential for development, cellular differentiation and homeostasis. Their dysregulation is also frequently associated with human malignancies. The JAK (Janus tyrosine Kinase)-STAT (Signal Transducer and Activator of Transcription) pathway represents one such signaling cascade whose evolutionarily conserved roles include cell proliferation and haematopoiesis. JAK belongs to a family of non-receptor protein tyrosine kinases of approximately 130 kDa, comprising of JAK1, JAK2, JAK3 and TYK2 (non-receptor Protein Tyrosine Kinase-2). STATs are latent...

JNK Pathway [ Details | Top ]
MAPKs (Mitogen-Activated Protein Kinases) are Serine-threonine protein Kinases that are activated in response to a variety of extracellular stimuli and mediate signal transduction from the cell surface to the nucleus. MAPKs are expressed in multiple cell types including Cardiomyocytes, Vascular Endothelial cells, and Vascular Smooth Muscle Cells. Three major MAPKs include ERKs (Extracellular signal-Regulated Kinases), JNKs (c-Jun NH(2)-terminal protein Kinases), and p38 Kinases. Members of the JNK/SAPK (Stress-Activated Protein Kinase) family of MAPKs are strongly stimulated by numerous Environmental Stresses...

MAPK family pathway [ Details | Top ]
Protein kinases are ubiquitous enzymes that are able to modulate the activities of other proteins by adding phosphate groups to their tyrosine, serine, or threonine amino acids (phosphorylation). MAPKs (Mitogen-Activated Protein Kinases), which are activated by many different signals, belong to a large family of serine/threonine protein kinases that are conserved in organisms as diverse as yeast and humans. MAPKs deliver extracellular signals from activated receptors to various cellular compartments, notably the nucleus, where they direct the execution of appropriate genetic programs, including activation of gene transcription...

MAPK Signaling [ Details | Top ]
Intracellular signaling cascades are the main routes of communication between the Plasma membrane and regulatory targets in various intracellular compartments. Sequential activation of Kinases is a common mechanism of signal transduction in many cellular processes. During the past decade, several related intracellular signaling cascades have been elucidated, which are collectively known as MAPK (Mitogen-Activated Protein Kinase) signaling cascades. The MAPKs are a group of protein Serine/threonine Kinases that are activated in response to a variety of extracellular stimuli and mediate ....

mTOR Pathway [ Details | Top ]
mTOR (Mammalian Target of Rapamycin) is a 289-kDa serine/threonine protein kinase and a member of the PIKK (Phosphatidylinositol 3-Kinase-related Kinase) family. The protein consists of a Catalytic Kinase domain, an FRB (FKBP12–Rapamycin Binding) domain, a putative Auto-inhibitory domain (Repressor domain) near the C-terminus and up to 20 tandemly repeated HEAT motifs at the Amino terminus, as well as FAT (FRAP-ATM-TRRAP) and FATC (FAT C-terminus) domains. The C-terminus of TOR is highly homologous to the catalytic domain of PI3K (Phosphatidylinositol 3-Kinase). TOR proteins are evolutionarily conserved from yeast...

NGF Pathway [ Details | Top ]
One of the most fundamental issues in current biology is how to maintain the critical balance between cell survival and death, both during development and in adulthood. Unrestrained cell division and survival leads to various forms of tumor, while excessive or premature cell death may lead to a variety of diseases such as Alzheimer's, Parkinson's and Multiple Sclerosis. In the nervous system, a family of Neurotrophins, which includes NGF (Nerve Growth Factor), BDNF (Brain Derived Neurotrophic Factor), NT3 (Neurotrophin3) and NT4/5 (Neurotrophin-4/5), maintains this critical balance of cell survival and death. The best characterized of these...

Notch Signaling [ Details | Top ]
The Notch signaling pathway is a fundamental signaling system used by neighboring cells to communicate with each other in order to assume their proper developmental role. Notch proteins are cell surface transmembrane-spanning receptors which mediate critically important cellular functions through direct cell-cell contact. Interaction between Notch and its proposed ligands initiates a signaling cascade that governs cell fate decisions such as differentiation, proliferation, and apoptosis in numerous tissue types. The core elements of the Notch signaling system include the Notch receptor...

P38 Signaling - New [ Details | Top ]
Cellular responses to many external stimuli involve the activation of several types of MAPK (Mitogen-Activated Protein Kinase) signaling pathways. MAPKs are a family of Serine/threonine kinases that comprise 3 major subgroups, namely, ERK (Extracellular signal-Regulated Kinase), p38 MAPK and JNK (c-Jun N-terminal Kinases). Despite the diversity in function and upstream signaling events, MAPKs are always activated by a highly conserved mechanism that involves phosphorylation on both a Thr (Threonine) and a Tyr (Tyrosine) residue catalyzed by a MAPK kinase. The phosphorylation motif Thr-Xaa-Tyr is located in the so called ac...

p53 Signaling [ Details | Top ]
p53 is a tumour suppressor protein that regulates the expression of a wide variety of genes involved in Apoptosis, Growth arrest, Inhibition of cell cycle progression, Differentiation and accelerated DNA repair or Senescence in response to Genotoxic or Cellular Stress. As a transcription factor, p53 is composed of an N-terminal Activation Domain, a central specific DNA Binding Domain, and a C-terminal Tetramerization Domain, followed by a Regulatory Domain rich in basic Amino acids. Having a short half-life, p53 is normally maintained at low levels in unstressed mammalian cells by continuous ubiquitylation and subsequent degradation by the 26S Proteasome...

PPAR Pathway [ Details | Top ]
Nuclear hormone receptors are transcription factors that bind DNA and regulate transcription in a ligand-dependent manner. PPARs (Peroxisome Proliferator-Activated Receptors) are ligand-inducible transcription factors that belong to the nuclear hormone receptor superfamily, together with the receptors for thyroid hormone, retinoids, steroid hormones and vitamin D that act as ligand-activated transcription factors. PPARs regulate gene expression by binding with RXR (Retinoid X Receptor) as a heterodimeric partner to specific DNA sequence elements termed PPRE (Peroxisome Proliferator Response Element)...

Ras Pathway [ Details | Top ]
Ras is a membrane-associated guanine nucleotide-binding protein that is normally activated in response to the binding of extracellular signals, such as growth factors, RTKs (Receptor Tyrosine Kinases), TCR (T-Cell Receptors) and PMA (Phorbol-12 Myristate-13 Acetate). Ras signaling affects many cellular functions, which includes cell proliferation, apoptosis, migration, fate specification, and differentiation. Ras acts as a binary signal switch cycling between ON and OFF states, which are characterized in terms of a small molecule, a guanine nucleotide, bound to the protein. In the resting cell, Ras is tightly bound to GDP...

SMAD Signaling Network [ Details | Top ]
Within the vasculature, TGF-Beta (Transforming Growth Factor-Beta) superfamily of secreted polypeptide growth factors play an important role in a variety of pathophysiologic processes, including angiogenesis, vascular remodeling, atherogenesis and in regulating cellular responses such as growth, proliferation, differentiation, migration, adhesion, survival, and specification of developmental fate. Apart from TGF-Beta, the superfamily also includes the Activins and the BMPs (Bone Morphogenetic Proteins). These factors signal through heteromeric complexes of Type-II and Type-I serine-threonine...

STAT3 Pathway - New [ Details | Top ]
STATs (Signal Transducers and Activators of Transcription) are a family of cytoplasmic proteins with SH2 (Src Homology-2) domains that act as signal messengers and transcription factors and participate in normal cellular responses to Cytokines and GFs (Growth Factors). STATs are activated via the tyrosine phosphorylation cascade after ligand binding and stimulation of the Cytokine Receptor-Kinase complex and Growth Factor-Receptor complex like the EGF (Epidermal Growth Factor), FGF (Fibroblast Growth Factor), PDGF (Platelet-Derived Growth Factor), GCSF (Granulocyte Colony Stimulating Factor), IL-6 (Interleukin-6), CNTF (Ci...

TGF-Beta Pathway [ Details | Top ]
Cell proliferation in somatic tissues, specification of cell fate during embryogenesis, differentiation and cell death are controlled by a multitude of cell–cell signals and loss of this control has devastating consequences. Prominent among these regulatory signals is the TGF-Beta (Transforming Growth Factor) super family, which comprises a large and diverse group of polypeptide morphogens including the prototype of the family–the TGF-Beta themselves as well as the BMPs (Bone Morphogenetic Proteins), and the GDFs (Growth and Differentiation Factors) (Ref.1). The members of the TGF-Beta family are expressed in distinct temporal...

TNF Signaling [ Details | Top ]
TNF (Tumor Necrosis Factor) is a multifunctional proinflammatory cytokine, with effects on lipid metabolism, coagulation, insulin resistance, and endothelial function. TNF has been considered as an anti-cancer agent since its discovery two decades ago. Members of the TNFR (TNF Receptor) superfamily can send both survival and death signals to cells (Ref.1). TNF family members play important roles in various physiological and pathological processes, including cell proliferation, differentiation, apoptosis, modulation of immune responses and induction of inflammation. TNF acts through two receptors, TNFR1 (TNF Receptor-1) and TNFR2 (TNF Receptor-2)....

TNF Superfamily Pathway [ Details | Top ]
Members of the TNF (Tumor necrosis factor) receptor superfamily play pivotal roles in numerous biological events in metazoan organisms. Ligand-mediated trimerization by corresponding homo- or hetero-trimeric ligands, the TNF family proteins, causes recruitment of several intracellular adaptors, which activate multiple signal transduction pathways. 29 TNF receptor family members have been identified in humans. Based upon their cytoplasmic sequences and signaling properties, these TNF receptors can be classified into three major groups (Ref.1). The first group, including Fas/ CD95/ Apo1/ APT1, TNFR1/ CD120a...

Transcription of mRNA [ Details | Top ]
Transcription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. Transcription can also be defined as a process that transcribes genetic information from DNA into RNA. In eukaryotes, it takes place in the nucleus, mitochondria and chloroplast. Transcription is performed by DNA-directed RNA Polymerases. Unlike DNA Polymerases, RNA Polymerases do not need a primer to start the reaction. While Bacteria contain only 1 RNA Polymerase, there are 3 different RNA polymerases in eukaryotic cells, which catalyzes the synthesis of three types of RNA...

WNT Signaling [ Details | Top ]
The development of tissues and organs in multicellular organisms is controlled by the interplay of several signaling pathways that cross talk to provide positional information and induce cell fate specification. Together with other families of secreted factors such as TGF-Betas (Transforming Growth Factor-Betas), FGFs (Fibroblast Growth Factors), Hedgehog and Notch proteins, WNT (Wingless-Type MMTV Integration Site Family) Growth Factors are crucially implicated in these processes. The WNT genes encode a large family of secreted protein growth factors that have been identified in animals from Hydra to Human...