Generalized Signaling Pathway Forms of Cell Signaling Speed of Signaling Response Response to Combinations of Signals Different Responses to Same Signal

Generalized Signaling Pathway Forms of Cell Signaling Speed of Signaling Response Response to Combinations of Signals Different Responses to Same Signal www.phwiki.com

Generalized Signaling Pathway Forms of Cell Signaling Speed of Signaling Response Response to Combinations of Signals Different Responses to Same Signal

Manning, Amanda, Managing Editor has reference to this Academic Journal, PHwiki organized this Journal Generalized Signaling Pathway Release signal molecule from signaling cell Bind in addition to activate receptor in target cell Activate intracellular signaling pathway Alter effector protein(s) to change cell behavior Forms of Cell Signaling Paracrine: signal molecule secreted in addition to acts locally Contact-dependent: signal molecule remains bound to signaling cell Endocrine: signal molecule secreted into bloodstream Synaptic: neurotransmitter acts at synaptic contacts

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Gap junctions: allow passage of small signaling molecules Autocrine: signaling cell signals to cells of the same type in addition to to itself Speed of Signaling Response Alterations to proteins already present occurs rapidly New gene expression in addition to protein synthesis occurs slowly Cell responds to set of signals based on its receptors Signals act in different combinations to effect behavior of cell Response to Combinations of Signals

Different receptors Same receptor coupled to different intracellular signaling machinery Different Responses to Same Signal Ion-channel-linked: neurotransmitter controls opening of ion channel G-protein-linked: intracellular signaling mediated by trimeric GTP-binding protein Types of Cell Surface Receptors Enzyme-linked: function as enzyme or directly associated with enzyme

Chain of molecular interactions between receptor in addition to target protein Small intracellular mediators (second messengers) Intracellular signaling proteins Relaying Signal Within Cell Some Ways as long as Intracellular Signaling Proteins to Relay Signal Generate small intracellular mediators Induced to interact with other signaling proteins Act as molecular switches Phosphorylation in addition to de-phosphorylation GTP binding in addition to hydrolysis Other mechanisms Induced Interactions of Signaling Proteins Intracellular signaling propagated by inducing protein interactions Interaction domains in signaling proteins Adaptor proteins

Molecular Switches Regulated by Phosphorylation Covalent attachment of phosphate by kinases, removal by phosphatases Different signaling proteins can be activated by phosphorylation or de-phosphorylation Molecular Switches Regulated by GTP Binding Active when GTP-bound; inactive when GDP-bound GTP binding by guanine nucleotide exchange factors, hydrolysis by GTPase activating proteins Target Cell Desensitization Decreased response to signal at particular level following prolonged exposure Negative feedback with short delay Signaling machinery modified, less responsive

Receptor-Mediated Activation of G Proteins Trimeric G protein (abg) Inactive when GDP bound to a Activation of receptor causes dissociation of a from bg in addition to exchange of GDP as long as GTP Activated a mediates signaling Turning off G proteins Stimulation of GTPase activity of a by interaction with target signaling protein or specific RGS Receptors linked to Gs activate adenylyl cyclase Converts ATP to cAMP, which acts a small intracellular mediator Activates cAMP-dependent protein kinase (PKA) Signaling by cAMP

Cholera & Pertussis Toxins Gs a subunit activates adenylyl cyclase Cholera toxin: ADP ribosylation of Gs (a); cannot hydrolyze GTP Gi a subunit inhibits adenylyl cyclase Pertussis toxin: ADP ribosylation of Gi (a); prevents binding to receptors Receptors linked to Gq activate phospholipase C-b PI(4,5)P2 cleaved to diacylglycerol in addition to IP3 IP3 opens channels in ER causing influx of Ca2+ into cytosol Diacylglycerol activates protein kinase C (PKC) Signaling by Inositol Phospholipids Cleavage by Phospholipase C-b

G protein-linked receptor kinases phosphorylate activated receptor Arrestin binding prevents G protein interaction, promotes endocytosis Receptor Desensitization Ca2+ as Small Intracellular Mediator Involved in PKC activation Binds calmodulin to regulate other proteins Activates CaM-kinases Activates calcineurin, a phosphatase, whose substrates include NFAT Calcineurin-NFAT Signaling in T Cells Calcineurin dephosphorylates, activates NFAT NFAT turns on genes as long as T cell activation Cyclosporin inhibits calcineurin in addition to thereby NFAT

Manning, Amanda Portico Managing Editor www.phwiki.com

Signaling Through Enzyme-Linked Receptors Lig in addition to binds to extracellular side of receptor Activates enzyme activity present or associated with cytoplasmic side Receptor tyrosine kinases Tyrosine kinase associated receptors Receptor tyrosine phosphatases Receptor serine/threonine kinases Receptor guanylyl cyclases Classes: Receptor Tyrosine Kinases Examples of RTK subfamilies Lig in addition to -induced receptor dimerization/oligomerization Cross-phosphorylation of receptors Activation of Receptor Tyrosine Kinases

Recruiting Intracellular Signaling Proteins Tyrosine phosphorylation generates binding sites as long as specific signaling proteins Most proteins that bind to activated receptor have SH2 domains Examples of SH2-Containing Proteins Enzymes, as long as example phospholipase C- Proteins that function as adaptors Receptor-Mediated Activation of Ras Ras is monomeric GTP binding protein Grb-2 adaptor has SH2 domain that binds activated receptor Grb-2 also binds Ras GEF, which activates Ras

Selective Estrogen Receptor Modulators Antagonists in some cell types in addition to agonists in others Tamoxifen as breast cancer therapy Raloxifene to help prevent osteoporosis

Manning, Amanda Managing Editor

Manning, Amanda is from United States and they belong to Portico and they are from  Birmingham, United States got related to this Particular Journal. and Manning, Amanda deal with the subjects like Affluent Lifestyle; Consumer Goods; Culture; Home Decorating; Regional Interest

Journal Ratings by Ecole Nationale d’Ingnieurs de Tarbes

This Particular Journal got reviewed and rated by Ecole Nationale d’Ingnieurs de Tarbes and short form of this particular Institution is FR and gave this Journal an Excellent Rating.