Apoptosis

Apoptosis   AKT Signaling Pathway Many cell-surface receptors induce production of second messengers like PIP3, phosphatidylinositol 3,4,5-trisphosphate, that convey signals to the cytoplasm from the cell surface. PIP3 signals activates the kinase PDK1, 3-phosphoinositide-dependent p ... Apoptotic DNA fragmentation and tissue homeostasis Apoptotic cell death can be triggered by many different cellular stimuli, resulting in activation of apoptotic signaling pathways including caspases (see Caspase Cascade pathway) and mitochondria (see Role of Mitochondria in Apoptotic Signaling pathw ... Apoptotic Signaling in Response to DNA Damage The cellular activation of the caspase cascade resulting in cell death is triggered by chemical damage to DNA which stimulates a sequence resulting in the cleavage of Bid in a manner similar to the binding of so called “death-receptors” or directly i ... ATM Signaling Pathway The ataxia telangiectasia-mutated gene (ATM) encodes a protein kinase that acts as a tumor suppressor. ATM activation by ionizing radiation damage to DNA stimulates DNA repair and blocks progression through the cell cycle. Mutation of the ATM gene ca ... Caspase Cascade in Apoptosis Apoptosis, programmed cell death, is triggered by a variety of stimuli, including cell surface receptors like FAS, mitochondrial response to stress, and cytotoxic T cells. Caspases are a class of cysteine proteases that includes several representativ ... cdc25 and chk1 Regulatory Pathway in response to DNA damage Cdc25 is a protein phosphatase responsible for dephosphorylating and activating cdc2, a crucial step in regulating the entry of all eukaryotic cells into the M-phase of the cell cycle. Cdc25 is phosphorylated throughout interphase but not in mitosis. ... D4-GDI Signaling Pathway D4-GDI (GDP dissociation inhibitor) is a negative regulator of the ras related Rho Family of GTPases. Since the rho GTPases promote cytoskeletal and membrane changes associated with apoptotic cell death, the removal of the D4-GDI block through its cl ... Degradation of the RAR and RXR by the proteasome Once retinoids are bound by the RAR/RXR heterodimer they became transcriptional activated. As a consequence they are degraded by the proteasome. Phosphorylation in the activation domain one (AF1) and presence of the activation domain 2 (AF2) triger t ... FAS signaling pathway ( CD95 ) Receptors in the TNF receptor family are associated with the induction of apoptosis, as well as inflammatory signaling. The Fas receptor (CD95) mediates apoptotic signaling by Fas-ligand expressed on the surface of other cells. The Fas-FasL interacti ... Free Radical Induced Apoptosis Oxidative stress is one factor that can trigger programmed cell death. Activated neutrophils responding to inflammatory stimulation produce reactive oxygen species like superoxide free radicals to kill invading bacteria, but these reactive oxygen spe ... GADD34-mediated Dephosphorylatoin of eIF2a in Stress Response Pathway Translation initiation is inhi Granzyme A mediated Apoptosis Pathway One mechanism used by cytotoxic T cells to kill tumor cells and virus-infected cells is the release of perforin and granzyme proteins. Perforin proteins form pores in the membranes of the attacked cell, allowing the entry of Granzyme A and Granzyme ... HIV Induced T Cell Apoptosis HIV infection is associated with immunosuppression caused by a dramatic reduction in the helper T cell population. The loss of helper T cells may be caused by HIV-induced apoptosis of both infected and uninfected helper T cells. HIV uses the CCR5 che ... HIV-I Nef: negative effector of Fas and TNF HIV infection leads to drastic declines in CD4 T helper cells, in part through apoptosis of uninfected cells. Apoptosis of uninfected cells may be induced through the expression of Fas ligand on the surface of HIV-infected cells, stimulating the Fas- ... Hypoxia and p53 in the Cardiovascular system Hypoxic stress, like DNA damage, induces p53 protein accumulation and p53-dependent apoptosis in oncogenically transformed cells. Unlike DNA damage, hypoxia does not induce p53-dependent cell cycle arrest, suggesting that p53 activity is differential ... Induction of apoptosis through DR3 and DR4/5 Death Receptors Apoptosis is specifically induced via signaling through a family of receptors known collectively as 'death receptors' including Fas, TNFR, DR3, -4 and -5. Death receptor ligands characteristically initiate signaling via receptor oligomerization, recr ... Mitochondrial Permeability Transition Pore Complex The mitochondrial permeability transition pore (MPTP) is a multiprotein complex located at the contact site between inner and outer mitochondrial membranes. MPTP plays an important role in the initiation and regulation of apoptosis. MPTP has been pre ... Multiple antiapoptotic pathways from IGF-1R signaling lead to BAD phosphorylation IGF-1R, the type 1 receptor for insulin-like growth factor, mediates cell survival and growth in response to its ligands IGF-1 and IGF-2. This tyrosine kinase receptor is widely expressed in many cell types and is a key mediator of growth. Overexpr ... Neuropeptides VIP and PACAP inhibit the apoptosis of activated T cells Vasoactive intestinal peptide (VIP) and the structurally related pituitary adenylate cyclase-activating polypeptide (PACAP), two neuropeptides present in the lymphoid microenvironment, elicit a broad spectrum of biological functions, including the mo ... Opposing roles of AIF in Apoptosis and Cell Survival Programmed cell death is induced by many different factors and involves numerous signaling pathways, some dependent on caspase proteases and others that are caspase independent. Like cytochrome C, AIF (apoptosis-inducing factor) is a protein found in ... OX40 Signaling Pathway Two key features of the immune system are the clonal expansion of B cells and T cells in response to antigens, and the potentiation of future immune responses by long-lived memory cells. CD4 expressing T cells require costimulatory signals along wit ... p53 Signaling Pathway p53 is a transcription factor who's activity is regulated by phosphorylation. The function is p53 is to keep the cell from progressing through the cell cycle if there is damage to DNA present. It may do this in multiple ways from holding the cell at ... Phosphatidylcholine Biosynthesis Pathway The main components of biological membranes are phosphoglyceride lipids composed of a glycerol unit esterified to two fatty acids and a polar alcohol group. The properties of phospholipids give lipid bilayer membranes their self-organizing structure. ... Proteasome Complex Attachment of the ubiquitin PTEN dependent cell cycle arrest and apoptosis PTEN is a tumor suppressor gene. Recombinant PTEN is capable of dephosphorylating phosphatidylinositol 3,4,5-triphosphate[PI(3,4,5)P3], the product of phosphatidylinositol 3 -kinase. Many of the cancer-related mutations have been mapped to the phosph ... Puma and Noxa Proteins Mediate p53- and Drug-induced Apoptotic Responses DNA damage can cause cell cycle arrest or apoptosis; both responses provoked by DNA damage require the p53 tumor suppressor. These responses are activated by different forms of imposed stress (cytokine deprivation, cytotoxic drugs, radiation) or by t ... RB Tumor Suppressor/Checkpoint Signaling in response to DNA damage Cell cycle checkpoint controls at the G1 to S transition and the G2 to M transition prevent the cell cycle from progressing when DNA is damaged. The ATM protein kinase detects DNA damage and in response to this activates DNA repair factors and inhibi ... Regulation of BAD phosphorylation The function of the pro-apoptotic molecule BAD is regulated by phosphorylation of three sites (ser 112,136 and 155). Phosphorylation at these sites results in loss of the ability of BAD to heterodimerize with the survival proteins BCL-XL or BCL-2. Ph ... Role of BRCA1, BRCA2 and ATR in Cancer Susceptibility BRCA1 and BRCA2 were identified genetically as breast cancer susceptibility genes when a single copy of the gene is mutated and are involved in the cellular response to DNA damage, including blocking cell cycle progression and inducing DNA repair to ... Role of MEF2D in T-cell Apoptosis Mef2 (Myocyte enhancer factor 2) transcription factors play a role in T-Cell Calcium Induced Apoptosis. Several factors regulate Mef2 transcription factors, including Map kinases and histone deacetylase (HDAC) enzymes. See also Control of s ... Role of Mitochondria in Apoptotic Signaling Mitochondria participate in apoptotic signaling pathways through the release of mitochondrial proteins into the cytoplasm. Cytochrome c, a key protein in electron transport, is released from mitochondria in response to apoptotic signals, and activate ... Role of nicotinic acetylcholine receptors in the regulation of apoptosis Nicotinic acetylcholine receptors are essential for neuromuscular signaling and are also expressed in non-neuronal tissues, where their function is less clear. Although nicotinic acetylcholine receptors are primarily known for their action as ligand ... SODD/TNFR1 Signaling Pathway The tumor necrosis factor (TNF) receptor superfamily contains several members with homologous cytoplasmic domains known as death domains (DD). The intracellular DD are important in initiating apoptosis and other signaling pathways following ligand bi ... Stress Induction of HSP Regulation Mammalian cells can respond to a variety of stresses such as heat, cold, oxidative stress, metabolic disturbance, and environmental toxins through necrotic or apoptotic cell death, while increased expression and phosphorylation of heat shock proteins ... The SARS-coronavirus Life Cycle Severe Acute Respiratory Syndrome (SARS) has affected thousands of individuals, causing fever, and pneumonia with a mortality rate estimated at 10-18%. A novel coronavirus has been identified as the cause agent and its genome has been sequenced. Hum ... TNFR1 Signaling Pathway TNFR1 (a.k.a. p55, CD120a) is the receptor for TNF(alpha) and also will bind TNF(beta). Upon binding TNF(alpha) a TNFR1+ cell is triggered to undergo apoptosis. This critical regulatory process is accomplished by activating the proteolytic caspase ca ... TNFR2 Signaling Pathway TNFR2 is the receptor for the 171 amino acid 19 kD TNF(beta) (a.k.a. lymphotoxin). TNF(beta) is produced by activated lymphocytes and can be cytotoxic to many tumor and other cells. In neutrophils, endothelial cells and osteoclasts TNF(beta) can lead ... Toll-Like Receptor Pathway The innate immune response responds in a general manner to factors present in invading pathogens. Bacterial factors such as lipopolysaccharides (LPS, endotoxin), bacterial lipoproteins, peptidoglycans and also CpG nucleic acids activate innate immuni ... Trefoil Factors Initiate Mucosal Healing Maintaining the integrity of the gastrointestinal tract despite the continual presence of microbial flora and injurious agents is essential. Epithelial repair requires restitution and regeneration. During restitution, epithelial cells spread and migr ... TSP-1 Induced Apoptosis in Microvascular Endothelial Cell As tissues grow they require angiogenesis to occur if they are to be supplied with blood vessels and survive. Factors that inhibit angiogenesis might act as cancer therapeutics by blocking vessel formation in tumors and starving cancer cells. Thrombo ...

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