We have built Pathway Central- a pathway study resource for you to find pathway reviews and presentation-ready pathway maps. You can browse the relevant pathways based on your research areas. Simply click on one of the ten research areas listed below, and the associated individual pathways will be listed. Or you can easily search the pathways of your interest with key words. Alternatively, you can view the complete list of pathways in the Pathway Central.

	Activation of cAMP-Dependent PKA	[ 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) ...

	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)....

	All-trans-retinoic acid signaling	[ Details | Top ]
	Retinoic Acid, a lipophilic molecule and a metabolite of Vitamin-A (all-trans-Retinol), affects gene transcription and modulates a wide variety of biological processes like Cell Proliferation, Differentiation, including Apoptosis. Retinoic Acid mediated gene transcription depends on the rate of transport of Retinoic Acid to target cells and the timing of exposure of Retinoic Acid to RARs (Retinoic Acid Receptors) in the target tissues. The all-trans-Retinoic Acid, the Carboxylic Acid form of Vitamin-A is of biological significance since it has high circulating levels than other isomers of Retinoic Acid. The targets of all-trans-Retinoic Acid and RARs include a multitude...

	Assembly of RNA Polymerase-II Initiation Complex	[ Details | Top ]
	The nuclei of all eukaryotic cells contain three different RNA Polymerases, designated I, II and III. Like the DNA Polymerase that catalyzes DNA replication, RNA Polymerases catalyze the formation of the phosphodiester bonds that link the nucleotides together to form a linear chain. The RNA Polymerase moves stepwise along the DNA, unwinding the DNA helix just ahead of the active site for polymerization to expose a new region of the template strand for complementary base-pairing. In this way, the growing RNA chain is extended by one nucleotide at a time in the 5’-to-3’ direction. The substrates are nucleoside triphosphates...

	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...

	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...

	Chromatin Remodeling	[ Details | Top ]
	The condensation of DNA into an ordered chromatin structure allows the cell to solve the topological problems associated with storing huge molecules of chromosomal DNA within the nucleus. DNA is packaged into chromatin in orderly repeating protein-DNA complexes called nucleosomes. Each nucleosome consists of approximately 146bp of dsDNA (double-stranded DNA) wound 1.8 times around a histone octamer (Ref.1). Two molecules each of H2A, H2B, H3, and H4 comprise the histone ramp around which the DNA superhelix winds. Stretches of DNA upto 100bp separate adjacent nucleosomes...

	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...

	Cytokine Network	[ Details | Top ]
	The immune system recognizes the presence of pathogens by several proteins that bind to molecules secreted by the pathogen or carried on their surface. The cells responsible for these immune responses include the B-Cells, T-Cells, macrophages, neutrophils, basophils, eosinophils, endothelial cells, or mast cells (Ref.1). These cells have distinct roles in the immune system, and communicate with other immune cells by cytokines, which control proliferation, differentiation and function of cells of the immune system. Furthermore, they are involved in processes of inflammation and in the neuronal, haematopoietic and embryonal development of an organism....

	DNA Methylation and Transcriptional Repression	[ Details | Top ]
	Transcriptional repression is an essential mechanism in the precise control of gene expression. Transcriptional repressor proteins associate with their target genes either directly through a DNA-binding domain or indirectly by interacting with other DNA-bound proteins. To inhibit transcription in a selective manner, a repressor protein can (1) mask a transcriptional activation domain, (2) block interaction of an activator with other components of the transcription machinery, or (3) displace an activator from the DNA. Furthermore, DNA response elements can exert allosteric effects on transcriptional regulators...

	DNA Repair Mechanisms	[ Details | Top ]
	Cells are constantly under threat from the cytotoxic and mutagenic effects of DNA damaging agents. Environmental DNA-damaging agents include UV light and ionizing radiation, as well as a variety of chemicals encountered in foodstuffs, or as air- and water-borne agents. Endogenous damaging agents include metabolites that can act as alkylating agents and the ROS (Reactive Oxygen Species) that arise during respiration. DNA repair enzymes continuously monitor chromosomes to correct damaged nucleotide residues generated by these exogenous and endogenous agents and exposure to carcinogens and cytotoxic compounds...

	EGF Pathway	[ Details | Top ]
	EGF (Epidermal Growth Factor) is a small 53 amino acid residue protein that is involved in normal cell growth, oncogenesis, and wound healing. This protein shows both strong sequential and functional homology with hTGF-Alpha (human type-Alpha Transforming Growth Factor), which is a competitor for EGF receptor sites. EGF binds to a specific high-affinity, low-capacity receptor on the surface of responsive cells known as EGFR (Epidermal growth factor receptor). EGFR is a member of the ErbB (Erythroblastic Leukemia Viral Oncogene Homolog) family receptors, a subfamily of four closely related receptor tyrosine kinases...

	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...

	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...

	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...

	Growth Hormone Signaling	[ Details | Top ]
	Most aging individuals die from atherosclerosis, cancer, or dementia; but in the oldest old, loss of muscle strength resulting in frailty is the limiting factor for an individual's chances of living an independent life until death. Three hormonal systems show decreasing circulating hormone concentrations during normal aging: (i) estrogen (in menopause) and testosterone (in andropause), (ii) dehydroepiandrosterone and its sulphate (in adrenopause), and (iii) the growth hormone/IGF1 axis (in somatopause). Physical changes during aging have been considered physiologic, but there is evidence that some of these changes are related to this decline in hormonal activity...

	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...

	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...

	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...

	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...

	NFAT and cardiac hypertrophy	[ Details | Top ]
	Cardiac failure, one of the largest health care burdens in the United States and other developed countries is often associated with prolonged and maladaptive cardiac hypertrophy, defined as a compensatory mechanism of the heart that helps to maintain cardiac output during pathological states with sustained increases in hemodynamic load (Ref.1). As cardiomyocytes lose the ability to divide soon after birth, cardiac hypertrophy offers an important adaptive response in vivo that allows the organism to maintain or increase its cardiac output. The adult myocardium responds to a wide array of intrinsic...

	NF-KappaB Family Pathway	[ Details | Top ]
	NF-KappaB (Nuclear Factor-KappaB) is a heterodimeric protein composed of different combinations of members of the Rel family of transcription factors. The Rel/ NF-KappaB family of transcription factors are involved mainly in stress-induced, immune, and inflammatory responses. In addition, these molecules play important roles during the development of certain hemopoietic cells, keratinocytes, and lymphoid organ structures. More recently, NF-KappaB family members have been implicated in neoplastic progression and the formation of neuronal synapses. NF-KappaB is also an important regulator...

	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...

	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)...

	PTEN Pathway	[ Details | Top ]
	Tumorigenesis is the result of abnormal activation of growth programs in the cells. Cancer cells escape normal growth control mechanisms as a consequence of activating mutations, or increased expression of one or more cellular protooncogenes, and/or inactivating mutations, or decreased expression of one or more tumor suppressor genes. Most oncogene and tumor suppressor gene products are components of signal transduction pathways that control cell cycle entry or exit, promote differentiation, sense DNA damage and initiate repair mechanisms, or regulate cell death programs....

	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...

	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...

	Toll-Like Receptors Pathway	[ Details | Top ]
	TLRs (Toll-like receptors) are transmembrane proteins expressed by cells of the innate immune system, which recognize invading microbes and activate signaling pathways that launch immune and inflammatory responses to destroy the invaders. Toll receptors were first identified in Drosophila. In mammals, the TLR family includes eleven proteins (TLR1−TLR11). Recently, two new members, TLR12 and TLR13 have been discovered in mouse, but not much information is known about them. Mammalian TLRs consist of an extracellular portion containing Leucine-rich repeats, a Transmembrane region and a Cytoplasmic tail...

	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...

	VEGF Pathway	[ Details | Top ]
	The formation of blood vessels occurs either by in situ differentiation of endothelial cell precursors (Angioblasts) and association of these cells to form primitive vessels, a process called Vasculogenesis, or by growth of preexisting vessels, a process called Angiogenesis. Vasculogenesis establishes the primary vascular plexus of the early embryo, whereas development of blood vessels during later embryogenesis and adult life occurs primarily by Angiogenesis. Angiogenesis is an integral feature of capillary sprouts from preexisting blood vessels. It is typically quiescent in the adult, except for pathological situations...

	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...