Cell-Cell Communication 3 Flashcards
What are Ion-Channel Coupled Receptors?
Multimeric proteins located in the plasma membrane, which form a passageway (ion channel) extending from one side to the other.
What are several stimuli that can open channels?
- Changes in voltage across the membrane
- Ligand (intra or extracellular)
- Mechanical stress (poorly uderstood)
Which cells contain Voltage-Gated Cation Channels?
Plasma membrane of all excitable cells: nerve, muscle, endocrine, egg cells.
What is the range of membrane potentials that causes Voltage-Gated Channels to open?
Channel’s Threshold.
What are the possible conformations of a Voltage-Gated Channel?
Open= On, Closed= Standby, Inactivated= Off
Where is the Ligand-Gated Ion Channel found?
Membrane of skeletal muscle cells, neurons of ANS, brain.
When does Ligand Channel open?
In response to ligand binding.
What is the other name for GPCR?
Metabotropic receptor.
How can GPCR be described?
Integral membrane protein with 7 domains and binds to a particular type of G protein.
What is the Heterotrimeric G Protein?
Membrane associated trimeric protein that relays the signal into the cell interior- alpha, gamma, delta.
What is the alpha unit of the Heterotrimeric G Protein?
GTPase and has a GDP bound in its inactive state.
T/F: Gα subunit exchange GDP (guanosine diphosphate) for GTP (guanosine triphosphate).
True.
T/F: GTPase hydrolyzes GDP to GTP and becomes inactive again.
False; GTP to GDP.
What are two types of G alpha subunit?
Stimulatory G Protein, Inhibitory G Protein.
What does the Stimulatory subunit activate?
Adenylyl cyclase
What does Adenylyl cyclase synthesize?
cAMP
What does cAMP Phosphodiesterase do?
Rapidly destroys cAMP.
Which enzyme does Gi inhibit?
Adenylyl cyclase.
T/F: Signaling mediated by GPCR tends to be slower and more complex than Inotropic receptors.
True.
T/F: The same signal can mediate one GPCR.
False; many different GPCRs.
