Alberts, Ch 15 - Cell Signaling Flashcards
Adaptor
General terma for a protein that functions solely to link two or more different proteins together in an intracellular signaling pathway or protein complex
Adenylyl cyclase
Membrane-bound enzym that catalyzes formation of cyclic aMP from ATP, important component of some intracellular signaling pathways
Akt
Serine/threonine protein kinase that acts in the PI-3-kinase/Akt intracellular signaling pathway involved especially in signaling cells to grom and survive, also called protein kinase B (PKB)
Arrestin
Member of aa family of proteins that contributes to GPCR desensitization by preventing the activated receptor from interacting with G proteins and servingas an adaptor to couple receptor to clathrin-dependent endocytosis
Beta-catenin
Multifunctional cytoplasmic protein involved in cadherin-mediated cell-cell adhesion, linking cadherins to the actin cytoskeleton, can also act independently as a transcription regulatory protein, has important role in animal development as part of Wnt signaling pathway
Calmodulin
Ubiquitous intracellular Ca2+-binding protein that undergoes a large conformation change when it binds Ca2+ allowing it to regulate the activity of many target proteins
Ca2+/calmodulin-dependent kinase (CaM-kinase)
Serine/threonine protein kinase that is activated by Ca2+/calmodulin, indirectly mediates effects of an increase in cytosolic Ca2+ by phosphorylating specific target proteins
CaM-kinase II
Multifunctional Ca2+/calmodulin-dependent protein kinase that phosphorylates itself and various target proteins when activated, found in most animal cells but is especially abundant at synapses in the brain and is involved in some forms ofsynaptic plasticity in vertebrates
Circadian clock
Internal cyclical process that produces a particular change in a cell or organism with a period of around 24 hours, for example sleep-wakefulness cycle in humans
Cone photoreceptor
Photoreceptor cell in vertebrate retina that is responsible for color vision in bright light
Contact-dependent signaling
Form of intracellular signaling in which signal molecules remain bound to the surface of the signaling cell and influence only cells that contact it
CRE-binding (CREB) protein
Transcription regulator that recognizes cyclic AMP response element (CRE)in the regulatory region of genes activated by cAMP, on activation by PKA, phosphorylated CREB recruit a transcriptional coactivatos to stimulate transcription of target genes
Cubitus interruptus (Ci)
Laatent transcription regulator that mediated the effects of Hedgehog
Cyclic AMP (cAMP)
Nucleotide that is generated from ATP by adenylyl cyclase in response to various extracellular signals, acts as a small intracellular ignaling molecule mainly by activating cAMP-dependent protein kinase (PKA)
cAMP phosphodiesterase
Specific enzyme that rapidly and continuously destros cAMP forming 5’-AMP
Cyclic GMP (cGMP)
Nucleotide that is generated from GTP by guanylyl cyclase in response various extracellular signals
cGMP phosphodiesterase
Specific enzyme that rapidly hydrolyzes and degrades cGMP
cAMP-dependent protain kinase
Enzyme that phosphorylates target proteins in response to rise in intracellular cAMP, also known as protein kinase A (PKA)
Cytokine receptor
Cell-surface receptor taht binds a specific cytokine or hormone and acts through JAK-STAT signaling pathway
Cytoplasmic tyrosine kinase
Enzyme activated by certain cell-surface receptors that transmits th receptor signal onward by phosphorylating target cytoplasmic proteins on tyrosine side chains
Delta
Single-pass transmembrane signal protein displayed on the surface of cells that binds to the Notch receptor protein on a neighboring cell activating a contact-dependent signaling mechanism
Dishevelled
Scaffold protein recruited to the Frizzled family of cell-surface receptors upon their activation by Wnt binding that helps relay the signal to other signaling molecules
Endocrine cell
Specialized animal cell that secretes a hormone into the blood, usually part of a glandd such asthe thyroid or pituary gland
Enzyme-coupled receptor
Major type of cell-surface receptor that has a cytoplasmic domain that either has enzymatic activity or is associated with an intracellular enzyme, enzymatic activity is stimulated by an extracellular ligand binding to the receptor
Ephrin
One of a family of membrane-bound protein ligands for the Eph receptor tyrosine kinases (RTKs) that stimulate repulsion or attraction responses that guide migration of cells and nerve cell axons during animal development
Extracellular signal molecule
Any secreted or cell-surface chemical signal that binds to receptors and regulates the activity of the cell expressing the receptor
Focal adhesion kinase (FAK)
Cytoplasmic tyrosine kinase present at cell-matrix junctionsinassciation with the cytoplasmic tailsof integrins
Frizzled
Family of cell-surface receptors that are seven-pass transmembrane proteins that resemble GPCRs in structure but do not generally work through activation of G proteins, activatedby Wnt binding to recruit scaffold proteins Dishevelled which helps relay sinal to other signaling molecules
GPCR kinase (GRK)
Member of a family of enzymes that phosphorylates multiple serines and threonines on a GPCR to produce receptor desensitization
G protein
Trimeric GTP-binding protein with intrinsic GTPase activity that couples GPCRs to enzymes or ion channels in the plasma membrane
G-protein-coupled receptor (GPCR)
Seven-pass cell-surface receptor that activates a G protein, which activates either an enzyme or ion channels in the plasma membrane
Gq
Class of G proteins that couples GPCRsto phospholipaseC-beta to activate inositol phospholipid signaling pathway
GTPase-activating protein (GAP)
Protein that binds to a GTPase and inhibits it by stimulating its GTPase activitycausing the enzyme to hydrolyze its bound GTP to GDP
GTP-binding protein aka GTPase
Enzyme that converts GTP to GDP, fall into two large families: trimeric G proteins and GTP-binding proteins, have an active GTP-boundform and an inactive GDP-bound form and frequently act as molecular switches in. Intracellular signaling pathways
Guanine nucleotide exchange factor (GEF)
Protein that binds to a GTPase and activatesit by stimulating it to release its tightly bounnd GDP allowing it to bind GTP in its place
Hedgehog protein
Secreted extracellular signal molecule that has many different roles controlling cell differentiation and gene expression in animal embryos and adult tissues, excessive signaling can lead to cancer
Hormone
Signal molecule secreted by an endocrine cell into the bloodstream which can then carry the signal to distant target cells
IkB
Inhibitory proteins that bind tightly to NFkB dimers and hold them in an inactive state within the cytoplasm of unstimulated cells
iHog
Protein with four or five immunoglobulin-like domains and two or three fibronectin-type-III-like domains, located on the cell surface and thought to serve as co-receptors for Hedgehog proteins
Inhibitory G protein (Gi)
Trimeric G protein that can regulate ion channels and inhibit the enzyme adenylyl cyclase in the plasma membrane
Inositol 1,4,5-triphosphate (IP3)
Small intracellular signaling molecule produced during activation of the inositol phospholipid signaling pathway, acts to release Ca2+ from endoplasmic reticulum
Inositol phospholipid signaling pathway
Intracellular signaling pathway that starts with the activation of phospholipace C and the generation of IP3 and diacylglycerol (DAG) from inositol phospholipids in the plasma membrane, DAG helpsto activate protein kinase C
Interaction domain
Compact protein module found in many intracellular signaling proteinsthat binds to a particular structural motif in another protein or lipid
IP3-gated Ca2+-release channel (IP3 receptor)
Gated Ca2+ channel in the ER membrane that opens on binding cytosolic IP3 releasing stored Ca2+ into the cytosol
Ion-channel-coupled receptor
Ion channel found at chemical synapses in postsynaptic plasma membrane of nerve and muscle cells, opensonly in response to the binding of a specificextracellular neurotransmitters, resulting inflow of ions leads to the genration of a local electrical signal in the postsynaptic cell, also known as ionotropic receptor
JAK-STAT signaling pathway
Signaling pathway activated by cytokines andsome hormones, providing a rapid route from the plasma membrane to the nucleus to alter gene transcription, involves cytoplasmic Janus kinases (JAK) and signal transducers and activators of transcription (STAT)
Janus kinases (JAKs)
Cytoplasmis tyrosine kinases associated with cytokine receptors which phosphorylate andactivate trancription regulator called STATs
Kinase cascade
Intracellular signaling pathway in which one protein kinaseactivated by phosphorylation, phosphorylates the next protein kinase in the sequenc and so on relaying the signal onward
Kinase
Enzyme that phosphorylates proteins
LDL-receptor-related protein (LRP)
Co-receptor bound by Wnr proteins in the regulation of beta-catenin proteolysis
Local mediator
Extracellular signal molecule. That acts on neighboring cells
MAP kinase module
Intracellular signaling module composed of three protein kinases with MAP kinase as third, activated by Ras protein in response to extracellular signals
Monomeric GTPase
Single-subunit enzyme that converts GTP to GDP,cycles between active GTP-bound form and inactive GDP-bound form, acts as molecular switch in intracellular signaling pathways
mTOR
Mammalian version of large protein kinase called TOR,involved in cell signaling, exists in two functionally distinct multiprotein complexes
Neurotransmitter
Small signal molecule secreted by presynaptic nerve cell at a chemical synapse to relay the signal to postsynaptic cell, i.e. GABA, acetylcholine, glutamate, glycine and neuropeptides
NFkB protein
Latent transcription regulator that is activated by various intracellular signaling pathways when cells are stimulated during immune, inflammatory or stress responses, also role in animal development
Nitric oxide (NO)
Gaseous signalmolecule that is widely used in cell-cell communication
NO synthase (NOS)
Enzyme that synnthesizes NO by deamination of arginine
Notch
Transmembrane. Receptor protein involved in man cell-fate choices in animal development, for example in specification of nerve cells from ectodermal epithelium, ligands are cell-surface proteins such as Delta and Serrate
Nuclear receptor superfamily
Intracellular receptors for hydrophobic signal molecules such as steroid and thyroid hormones and retinoic acid, receptor-ligand complex acts as a transcription factor in nucleus
Olfactory receptors
G-protein-coupled receptors on the modified cilia of olfactory receptor neurons thatrecognize odors, receptors activate adenylyl cyclase via olfactory-specific G protein (Golf) and resultant increase in cAMP open cAMP-gated cation channels, leading to depolarization and initiation of nerve impulse
Paracrine signaling
Short-range cell-cell communication vie secreted signal molecules that act on neighboring cells
Patched
Transmembrane protein predicted to cross membrane 12 time, much in intracellular vesicles and some on cell surface where binds Hedgehog protein
Phosphoinositide
Lipid containing phosphorylated inositol derivative, minor component of plasma membrane. But important in demarking different membranes and for intracellular signal transduction in eukaryotes
PI 3-kinase
Membrane-bound enzyme that is component of PI-3-kinase-Akt intracellular signaling pathway, phosphorylates phosphatidylinositol 4,5-bisphosphate at 3 position on inositol ring to produce PIP3 docking sites in membrane. For other intracellular signaling proteins
Phospholiase C (PLC)
Membrane-bound enzyme that cleaves inositol phospholipids to produce PIP3 and diacylglycerol (DAG) in inositol phospolipid signaling pathway, PLC-beta activated by GPCRs via G proteins, PLC-gamma activates by RTK
Phosphatidylinositol 4,5-bisphosphate (PIP2)
Membrane inositol phospholipid that is cleavedby PHC into IP3 and DAG at the beginning of inositol phospholipid signaling pathway, can also be phosphorylated by PI 3-kinase to produce PIP3 docking sited for signaling proteins in PI-3-kinase-Akt signaling pathway
Phosphrylation
Reaction in which a phosphate group is covalently coupled to another molecule
PI-3-kinase-Akt pathway
Intracellular signaling pathway that stimulates animal cells to survive and grow
Pleckstrin homology (PH) domain
Protein domain found in some intracellular signaling proteins, bind phosphatidylinositol 3,4,5-triphosphate (PIP3) bringing signaling protein to plasma membrane when PI 3-kinaseis activated
Primary cilium
Short, single, nonmotile cilium lacking dynein that arises from a centriole andprojects from the surface of many animal cell types, some signaling proteins are concentrated here
Protein kinase
Enzyme that transfers terminal phosphate group of ATP to serine, threonine or tyrosine of a target protein
Protein kinase C (PKC)
Ca2+-dependent protein kinase that, when activated by DAG and increased in cytosolic Ca2+, phophorylates target protein on specific serine and threonine residues
Protein phosphatase
Enzyme that catalyzes phosphate removal from amino acids of target protein
Protein tyrosine phosphatase
Enzyme that removes phosphate groups from phosphorylated tyrosine residues on proteins
Ras
Small family of proto-oncogenes that are frequently mutated in cancers, each of which produces Ras monomeric GTPase
Ras protein
Monomeric GTPase of Ras superfamily that helps to relay signals from cell-surface receptor tyrosine kinase receptors to the nucleus in response to signals that stimulate cell division
Ras superfamily
Large superfamily of monomeric GTPases of which Ras is the prototypical member
Ras-GAP
Ras GTPase-activating proteins, increase rate of hydrolysis of bound GTP by Ras inactivating it
Ras-GEF
Ras guanine nucleotide exchane factor, stimulate dissociation of GDP andsubsequent uptake of GTP activating Ras
Ras-MAP-kinase signaling pathway
Intracellular signaling pathway that relays signals from activaed receptor tyrosine kinases to effecor proteins in cell including transcription regulators in nucleus
Receptor
Any protein that binds a specific signal molecule and initiates a response in the cell, some on cell surface, others inside
Receptor serine/threonine kinase
Cell-surface receptor with extracellular ligand-binding domain and intrcellular kinase domain that phosphorylates signaling proteins on serine or threonine residues in response to ligand binding
Regulator of G protein signaling (RGS)
GAP protein that binds to trimeric G protein and enhances its GTPase activity helping to limit G-protein-mediated signaling
Receptor tyrosine kinase (RTK)
Cell-surface receptor with extracellular ligand-binding domain and intracellular kinase domain that phosphorylates signaling protein on tyrosine residues in resonse to ligand binding
Rheb
Monomeric Ras-related GTPase that in its active form activates mTOR which promotes cell growth
Rho family
Family of monomeric GTPases within Ras superfamily involved in signaling the rearrengementof the cytockeleton, include Rho, Racand Cdc42
Rho
Member of Rho family that regulate actin and microtubule cytoskeletons, cell-cycle progression, gene transcription and membrane transport
Rhodopsin
Seven-span membrane protein of GPCR family that acts as light sensorin rod photoreceptor cells in vertebrate retin, contains light-sensitive prosthetic group retinol
Rod photoreceptor
Photoreceptor cell in retina that is responsible for noncolor vision in dim light
Ryanodine receptor
Regulated Ca2+ channel in ER membrane that open in response to rising Ca2+ levels and thus amplifies Ca2+ signal
Scaffold protein
Protein that binds groups of intracellular signaling proteins into a signaling complex, often anchoring the complex at a specific location in the cell
Second messenger
Small intracellular signaling molecule that is formed or released for action in response to extracellular signal and helps to relay signal within the cell, i.g. cAMP, cGMP, IP3, Ca2+ and DAG
Serine/threonine kinase
Enzyme that phosphorylates specific proteins on serine or threonine
SH2 domain
Src homology region , protein domain present in many signaling proteins, binds short amino acid sequence containing phosphotyrosine
Smad family
Latent transcription regulators that arephosphorylated and activated by receptor serine/threonine kinases and carry the signal from cell surface to nucleus
Smoothened
Seven-pass transmembrane protein with a structure very similar to GPCR but does not act as Hedgehog receptor or as activator of G protein, controlled by Patched and iHog proteins
Src
Family of cytoplasmic tyrosine kinases that associate with the cytoplasmic domains of some enzyme-linked cell-surface receptors that lack intrinsic tyrosine kinase activity, transmit signal onward by phosphorylating receptor itself and specific intracellular signaling proteins on tyrosine
STAT
Signal transducer and activator of transcription, latent transcription regulator that is activated by phosphorylation by Janus kinases and enters nucleus in response to signaling from receptors of cytokine receptor family
Steroid hormones
Hormones that are hydrophobic lipid molecules dericed from cholesterol that activate intracellular nuclear receptors, include cortisol, estrogen and testosterone
Stimulatory G protein (Gs)
G protein that activates enzyme adenylyl cyclase and thus stimulates production of cAMP
Synaptic signaling
Intracellular signaling performed by neurons that transmit signals electrically along their axons and release neurotransmitters at synapses
TGF-beta superfamily
Transforming growth factor-beta superfamily, large family of structurally related secreted proteins that act as hormones andlocal mediators to control wide range of functions in animals, also during development
TOR
Large, serine/threonine protein kinase that is activated by PI-3-kinase-Akt signaling pathwayand promotes cell growth
Tyrosine kinase
Enzyme that phosphorylates specific proteins on tyrosines
Tyrosine-kinase-associated receptor
Cell-surface receptor that functions similarly to RTKs except that kinase domain encoded by seperate gene and is noncovalently associated with the receptor polypeptide chain
Wnt protein
Member of family of secreted signal proteins that have many different role in controlling cell differentiation, proliferation and gene expression in animal embryos and adult tissues
Wnt/beta-catenin pathway
Signaling pathway activated by binding of Wnt protein to its cell-surface receptos, has several branches, major branch activation causes increased amounts of beta-catenin to enter nucleus where it regulates transcription of genes controlling cell differentation and proliferation, overactivation can lead to cancer
Adaptation
Adjustment of sensitivity following repeated stimulation, mechanism that allows a cell to react to small changes in stimuli even against high background level of stimulation
