Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
Cell surface Receptor:
3 categories |
1. Ion channel coupled receptors
2. G-Protein Coupled receptors 3.Enzyme coupled receptor |
|
Fact about extracellular signal molecules
|
there are multiple receptors for a single ESM
ex. Acetocholine = heart and skeletal muscle cells. |
|
G-Protein coupled Receptor:
Size |
Largest family among cell surface receptors.
-7 transmembrane proteins - ~20 different types in mammalian cells |
|
G-Protein coupled Receptor:
Variety |
Wide variety of signal molecules:
-hormones, local mediators, neurotransmitters, proteins, small peptides, AA derivative. |
|
G-Protein coupled Receptor:
Useful |
good targets for drug development
|
|
G-Protein coupled Receptor:
old |
ancient protein conserved in all eukaryotic cells:
-rhodopsin, olfactory receptor, insect pheromone receptor, mating factor receptor(in yeast, similar in bacteria) |
|
Stimulation of GPCR
|
activates G protein subunits
-alpha, beta, gamma(trimeric) |
|
Inactive G protein subunit
|
trimer with a GDP bound a subunit
|
|
Fact about G subunit
|
only alpha and gama are tethered to membrane via lipid subunit
|
|
G protein cell receptor:
Function |
if ligand bound, functions as GTP exchange factor for the a unit
|
|
GTP bound subunits
|
Both a and bGamma can interact with target proteins at plasma membrane
|
|
a subunit facts
3 |
-dissociates when GTP activated
-Has intrinsic GTP hydrolysis activity -GTP bound: reassemles with BY complex(inactive form) |
|
G protein cell receptor:
strength |
Strength is dependent on how long subunits are bound to target proteins
|
|
what does G protein regulate?
|
-Some directly regulate ion channels(ex. in cardiac muscle cells)
-some activate membrane bound enzymes |
|
G proteins and plants
|
they are very rare in plants
-arabidopsis only has 1 G-protein gene |
|
Cyclic AMP pathway
|
can activate enzymes and turn on genes
|
|
AMP cycle
|
ATP(3 phosphates)-->adenyl cyclase (2 P leave)-->Cyclic AMP( P connects to OH)-->Cyclic AMP phosphodiesterase(H2O in)--> AMP
|