Voltage Gated Ca Channels Flashcards
What is the primary subunit that forms the ion-conducting pore of voltage-gated Ca²⁺ channels?
A1
What are the auxiliary subunits
B
A2o
Y
What role do β subunits play in voltage-gated Ca²⁺ channels?
Anchor
Which voltage-gated Ca²⁺ channel subunit is primarily responsible for the pore’s ion selectivity?
A1
What type of Ca channel is CaV1.1-1.4
L-type
Which type of voltage-gated Ca²⁺ channel is associated with lower activation thresholds and faster kinetics?
T type Ca channels CaV3.1-3.3
What type of Ca channel is associated with high voltages activated channels and log lasting currents
L type
Which type of calcium channels are responsible for muscle contraction and hormone secretion
L type
Which CaV channel subtype is primarily involved in neurotransmitter release?
P/Q type CaV2.1
What role do N-type CaV2.2 channels play in the nervous system?
Mediated neurotransmitter release at pre-synaptic terminal
What type of channel is CaV 2.2
N type
Which CaV channel subtype is known for having a low activation threshold and fast inactivation?
T type CaV3.1-3.3
What is the primary function of CaV1.2 channels?
Excitation contraction coupling
What type of channels are low voltage activated channels with transient fast inactivating currents
T type CaV3.1-3.3
Which kinases are primarily involved in the phosphorylation of CaV channels?
PKA and PKC
How does phosphorylation by PKA affect CaV channels?
Enhances Ca²⁺ currents by increasing channel opening
What effect does PKC phosphorylation have on CaV channels?
Enhance or inhibit channel activity
Effect of Gβγ subunits on CaV channels
Inhibit them decreasing Ca entry
What subunit does βγ interact with to cause a conformational change
A1
How does the activation of Gq-coupled receptors affect CaV channels?
increased intracellular calcium levels, which can enhance the activity of CaV channels via the phospholipase C (PLC)
What is the effect of Gi-coupled receptor activation on CaV channels?
inhibits CaV channels through the βγ subunit, decreasing calcium influx
How does calcium-induced calcium release (CICR) relate to CaV channels?
Activation of CaV channels allows calcium entry, which can trigger further release of calcium from the endoplasmic reticulum via ryanodine receptors, amplifying the intracellular calcium signal.
What are channelopathies?
Mutations in ion channel genes
Name a channelopathy associated with mutations in the CaV1.1 channel.
Hyperkalemic periodic paralysis
What condition is caused by mutations in the CaV1.2 channel?
Timothy syndrome
What condition is due to mutation in CaV2.1
Episodic axtasia type 2
Name a channelopathy linked to CaV2.2 (N-type) channels.
LEMs
What are CaV3.1 channels associated with in terms of clinical conditions?
Absent seizures
Which calcium channel mutation is implicated in Familial Hemiplegic Migraine (FHM)?
CaV2.1
