Cell Signaling and Signal Transduction Flashcards
__________ receptors convert chemical signals into electrical ones.
Ion channel-linked receptors
Which compound does PKA phosphorylate in the nucleus and what affect does this have?
CREB. CREB binds the target gene which leads to an increase in transcription, followed by translation.
Inositol Phospholipid Pathway
- Signaling molecule binds to a G-protein linked receptor
- G-protein alpha subunit activated
- The alpha subunit activates a phospholipase
- Phospholipase breaks down Pl 4,5-bisphosphate
- The break down of Pl 4,5-bisphosphate results diacylglycerol and IP3
- IP3 will bind to IP3 receptors on the ER membrane
- Calcium released
- Calcium can activate protein kinase C
- Protein kinase C interacts with diacylglycerol which will result in further downstream affects.
A receptor signal molecule that is activated by cleavage?
Notch
What occurs in primary transduction? What steps follow?
The transmembrane protein binds the ligand
A number of intracellular relays can occur so that signal can be modified, amplified, and divered to multiple targets.
How is the alpha subunit of the G-protein inactivated?
The hydrolysis of the GTP by the alpha subunit inactivates this subunit and causes it to dissociate from the target protein
Examples of Small Signaling Molecules that Bind to Nuclear Receptors
Cortisol
Estradiol
Testosterone
Thyroxine
Vitamin D
Retinoic acid
What component downregulated the alpha subunits GTPase activity? What affect does this have?
GTP gamma S; helps the alpha subunit to remain active for a very long time
Bifurcation proteins
Split the cell into 2 signaling pathways
________ and ________ depend on G-protein-linked receptors that regulate cyclic-nucleotide- gated ion channels.
Smell; vision
Example of a metabotropic recepter pathway
- The Metabotropic receptor binds to the G-protein
- Adenylate cyclase is activated
- cAMP is activated
- Protein Kinase A is activated
- The channel will close and no potassium will be able to exit the cell
* Indirect affect
In the intracellular pathway, in what way are the metabolic enzyme, gene regulatory protein, and cytoskeletal protein affected by the cascade?
Metabolic emzyme: Altered metabolism
Gene regulatory protein: Altered gene expression
Cytoskeletal protein: Altered shape or movement
How many subunits does an inactive protein kinase A have?
4 (2 regulatory and 2 catalytic)
What happens to neurotransmitters once they are released into the synpatic cleft and bind to the receptor?
The neurotransmitters are broken down by enzymes found in the synapse. They are then taken up by glia cells or recycled back intot he nerve cell
Adaptor protein
Link one signal pathway to another signal pathway
What does PDGF, FGF, and NGF stand for?
Platelet derived growth factor receptor, fibroblast growth factor, and nerve growth factor
What happens in the cAMP pathway?
cAMP acts on the protein kinase A
Once cAMP binds to PKA, the subunits break up and you get the active PKA catalytic subunits
Intracellular signaling proteins that act as molecular switches
Signaling by Phosphorylation
Signaling by GTP-binding protein
Scaffold proteins
Combine multiple signal proteins together forming a complex
Which type of channels found in gap junctions allow for bidirectional flow? What type of response does this allow for?
Connexon; Fast
What happens in intracellular signaling?
Small hydrophobic molecules cross the membrane and float into the nucleus, where they bind to the intracellular recptors and can cuase changes to gene transcription
__________ make the effects of PKA and other protein kinases transitory.
Protein phosphatases
Enzyme- linked Cell-Surface Receptors are activated by ___________
Growth factors
____________ is a signaling molecule that can activate both ionotropic and metabotropic receptors
Glutamate
