Signal Transduction Perrino Flashcards
what type of signaling is a process in which one cell creates signaling molecules that is recognized by neighboring target cells
Paracrine signaling
what type of signaling is the release of signaling molecules into the blood stream where they can bind to receptors that are far from the sources of release.
Endocrine Signaling
synaptic signaling involves a target cell and a (blank) forming a synapse
neuron
what type of signaling does not require high affinity ligand binding?
synaptic signaling
what type of signaling requires high affinity ligand binding?
endocrine signaling
what type of signaling molecule is common in endocrine signaling?
Hormones
what is the common “generic” intracellular signaling pathway?
extracellular signaling molecule binds to receptor protein– intracellular signaling protein cascade–effector proteins–resulting in altered metabolism, altered gene expression, or altered cell shape or movement.
what are 4 methods cells use for signaling?
cell-surface receptors
contact-dependent
intracellular receptors
gap junctions
what type of signaling involves a group of identical signaling cells?
autocrine signaling
what type of signaling uses vast distances and a large volume of signaling molecules?
endocrine signaling
what type of signaling uses very small distances with a small volume of signaling molecules?
synaptic signaling
in which type of signaling is the concentration of signaling molecules very high?
synaptic signaling
what do selective serotonin reuptake inhibitors (SSRIs) do?
the act within the brain to increase the amount of Serotonin in the synaptic gap by inhibiting its reuptake.
cells are programmed to respond to specific combinations of signaling. what are the 4 different generic signals?
Survive
grow and divide
differentiate
Die
what is contact-dependent signaling?
membrane bound signaling molecules directly interact with receptor on adjacent targeted cell.
what are two types of molecular switches?
singling by phosphorylation & Signaling by GTP-Binding
which molecular switch always turns proteins/pathways on?
GTP-Binding signaling
which molecular switch can turn a proteins/pathway on or off?
Signaling by phosphorylation
what is the inactive form and the active form in GTP-Binding
GDP-inactive, GTP-active binding
phosphorylation requires which high energy molecule to turn something on?
ADP to ATP
switches allow for the (blank) of signals
integration
what to signaling complexes allow for?
specificity by restricting localization of the integrated signal
what allows for the assembly of molecular switch complexes?
modular binding domains of signaling proteins.
ex. RTKs binding with PTB docking proteins which bind with SH2 domains which bind to membrane bound docking sites and other scaffolding proteins.
as the number of activator molecules that are bound to the effector protein increase, the slope of the activation curve (blank)
increases
describe threshold activation
some effector proteins require binding of multiple signaling molecules in order to reach a level for activation can occur
what type of binding is an “all or nothing” response?
threshold activation- no activity is seen during the build up of signaling molecules till the threshold is achieved.
what are the 5 mechanisms of desensitization?
Receptor sequestration receptor down regulation receptor inactivation inactivation of signaling protein production of inhibitory proteins
what is receptor sequestration?
receptors are removed from cell membrane and internalized
what is receptor down-regulation?
receptor number is decreases via lysosomal degradation.
what type of desensitization involves the receptor being inactivated via phosphorylation or binding of another molecule to in intracellular domain?
Receptor- Inactivation
what type of desensitization: receptor is activated but the protein within the signaling pathway is inactivated , causing a block in the pathway
inactivation of signaling protein
what is the production of inhibitory protein?
another protein inhibits pathway or signaling cascade
define positive feedback
product of a reaction or signaling pathway increases its own output.
define negative feedback
product formed reduces its formation of more product
a ligand binds a substrate activating it, an enzyme than binds increasing its activity, with the addition of yet another enzymes the activity is further increase ( a switch like behavior). This is an example of what?
accelerating positive feedback
which type of ligands typically have intracellular receptors?
Steroid hormones
what are 2 other important classes of signaling molecules that bind to intracellular receptors?
vitamind D3 and retonic acid
steroid hormones are (blank)
transcription factors
Rapid responses from signaling transduction most likely include change in (blank)
protein function
slow responses (mins to hrs) from signaling transduction most likely include (blank)
altered protein synthesis
singling molecules in the circulation are usually carried by what?
carrier proteins- signaling molecules are normally hydrophobic so they pass through cell membrane easily but need help with migration through the circulation.
prostaglandins (PGs) synthesis from membrane phospholipids is an example of (blank)
autocrine signaling
what to PGs mediate?
pain responses, as in headaches, arthritis, menstrual cramps etc..
PG synthesis is inhibited at phospholipase A2 stage by what?
corticosteroids
PG synthesis inhibited at cyclooxyhenase stage by what?
NASIDs like ibuprofen
what are the stages of prostoglandin synthesis?
membrane phospholips–arachidonic acid (extended)– arachidonic acid folded confirmation–prostaglandin
what are three cell types that can respond to acetylcholine (ACh)
Skeletal muscle cell, heart muscle, salivary gland cell.
Nitric Oxide (NO) as an important signaling molecule with an (blank) receptor
intracellular receptor
erectile dysfunction medication such as Viagra work by doing what?
inhibiting the breakdown of cyclic GMP by inhibiting phosphodiesterase (PDE) from breaking down cGMP
