CaV3.2 | voltage-dependent, T type, alpha 1H subunit calcium channel
Family:
Calcium channels
Subgroups:
L-Type (CaV1.1–CaV1.4), P/Q-Type (CaV2.1), N-Type (CaV2.2), R-Type (CaV2.3), T-Type (CaV3.1–CaV3.3)
Topology:
Six transmembrane alpha helices (S1–S6), total of four homologous domains make up the tetrameric alpha subunit structure
Assembling:
One large alpha subunit forms a functional channel, accessory subunits ( α1, α2δ, β1-4, and γ) are crucial for robust expression, they functionally modulate the alpha subunit
CaV3.2: Background Information
CaV3.2 give rise to the T-type currents: Low-voltage-activated calcium channels are referred to as 'T' type because their currents are both transient, owing to fast inactivation, and tiny, owing to small conductance. T-type channels are thought to be involved in pacemaker activity, low-threshold calcium spikes, neuronal oscillations and resonance, and rebound burst firing. T-type channels serve pacemaking functions in both central neurons and cardiac nodal cells and support calcium signaling in secretory cells and vascular smooth muscle. They may also be involved in the modulation of firing patterns of neurons which is important for information processing as well as in cell growth processes.
In the adrenal zona glomerulosa, CaV3.2 participates in the signaling pathway leading to aldosterone production in response to either AGT/angiotensin II, or hyperkalemia. Furthermore, CaV3.2 has a proexcitatory impact in small-diameter nociceptors expressing mechanoactivated channels. It is expressed in primary sensory neurons of the dorsal root ganglion (DRG) and contributes to nociceptive and neuropathic pain. CaV3.2 participates in the development of inflammatory hyperalgesia and might play an important role in the sub-acute phase of inflammatory pain due to increased co-localization with TRPV1 receptors.
Gene:
CACNA1H
Human Protein:
UniProt O95180
Tissue:
Brain, ovary, placenta, vascular smooth muscle
Function/ Application:
Pacemaker activity (brain, heart), hormone secretion, fertilization
Pathology:
Angina, epilepsy (CAE6, EIG6), sleep, breast cancer, autism, pain, cardiac hypertrophy, Hyperaldosteronism, Familial, Type Iv
Interaction:
GNG2, KCNMA1, KDM5B, CACNA1s, CACNBs, CACNGs, NCAM
Modulator:
Kurtoxin, mibefradil, flunarizine, zonisamide, bepridil, nifedipine
Assays:
Patch Clamp: whole cell, room temperature
Particularities:
CaV channels often show a rundown phenomenon. Adequate intra- and extrcellular solutions are essential for a good data quality.
Recommended Reviews:
Catterall WA, Perez-Reyes E, Snutch TP, Striessnig J (2005). "International Union of Pharmacology. XLVIII. Nomenclature and structure-function relationships of voltage-gated calcium channels". Pharmacol Rev. 57 (4): 411–25.
Data and Applications
CaV3.2 - T-Type Calcium Channels
Port-a-Patch data and applications:
Cells were kindly provided by Cytomyx Millipore.
Shown are raw current traces (top left) and average peak current data (top right) of the current voltage relationship of CaV3.2 (T-type Ca2+- Channel) stably expressed in HEK293 cells. Activation and Inactivation plots were constructed (bottom). Half-activation and half-inactivating potentials were determined as -32 mV and -65 mV, respectively.
CaV3.2 - Raw Currents
SyncroPatch 96 (a predecessor model of SyncroPatch 384PE) data and applications:
Cells were kindly provided by Cytomyx Millipore, UK.
Shown are raw current responses of CaV3.2 (HEK293) to a current voltage relationship step protocol. 75 % of the cells had a seal above 0.5 GΩ (color coded in green). The corresponding online analysis of this experiment is shown in the data set CaV3.2 - Online Analysis.
CaV3.2 - Online Analysis
SyncroPatch 96 (a predecessor model of SyncroPatch 384PE) data and applications:
Cells were kindly provided by Cytomyx Millipore.
Shown are individual current voltage relationships of CaV3.2 (HEK293) obtained in a single run on the SyncroPatch 96. 75 % of the cells had a seal above 0.5 GΩ (color coded in green). The corresponding raw current traces of this experiment are shown in the data set CaV3.2 - Raw Currents.
CaV3.2 - Current-to-Voltage Relationship
Patchliner data and applications:
Cells were kindly provided by Millipore
Representative current responses of an individual cell expressing Ca 2.2 to a standard voltage protocol. The average mean current at -20 mV of all recorded cells was -785 ± 110 pA (n = 12).
CaV3.2 - Channel Blockers
Port-a-Patch data and applications:
Cells were kindly provided by Cytomyx Millipore.
Shown are raw current traces (top) and average dose response curves (bottom) of CaV3.2 (T-type Ca2+- Channel) block by compounds as indicated. CaV3.2 is stably expressed in HEK293 cells. IC50s were 863 nM (Mibefradil), 27 μM (Nifedipine) and 52 μM Amiloride.
Application Notes
CaV3.2 - "High Throughput Pharmacology of CaV3.2 Channels on Nanion’s SyncroPatch 384PE"
SyncroPatch 384PE (a predecessor model of the SyncroPatch 384i) application note: 
(0.6 MB)
Cells were kindly provided by Millipore.
CaV3.2 - "Characterization of CaV3.2 on Nanion's Port-a-Patch"
Port-a-Patch application note: (0.7 MB)
Cells were kindly provided by Millipore.
CaV3.2 - "Characterization of CaV3.2 (HEK293) on Nanion's Patchliner"
Patchliner application note: (0.6 MB)
Cells were kindly provided by Millipore.
