Succinate Dehydrogenase - Succinate-Coenzyme Q Reductase

Family:
Gene family: Mitochondrial complex II

Structure:
The protein complex consists of four protein subunits: succinate dehydrogenase, (SDHA); succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial, (SDHB); succinate dehydrogenase complex subunit C, (SDHC) and succinate dehydrogenase complex, subunit D, (SDHD)

Function:
The enzyme is found in the inner mitochondrial membrane in eukaryotes and the plasma membrane of many aerobic or facultative bacteria.
It catalyzes succinate oxidation in the citric acid cycle and transfers the electrons to quinones in the membrane, thus constituting a part of the aerobic respiratory chain (known as complex II). Complex 2 is a parallel electron transport pathway to complex 1, but unlike complex 1, no protons are transported to the intermembrane space in this pathway. Therefore, the pathway through complex 2 contributes less energy to the overall electron transport chain process.

Succinate Dehydrogenase: Background Information

Ca_V2.1, also known as brain calcium channel I, gives rise to P and/or Q-type calcium currents and is predominantly expressed in neuronal tissue. Localized to the presynaptic membrane of many types of neurons, Ca_V2.1 ion channels are involved in triggering neurotransmitter release via both, vesicle release and postsynaptic calcium entry.

Gene:
CACNA1A

Human Protein:
UniProt O00555

Tissue:
Brain

Function/ Application:
Pre-synaptic Ca²⁺ influx and neurotransmitter release in neurons, fast synaptic transmission

Pathology:
Migraine (FHM-1), ataxia (EA-2, SCA6), Benign paroxysmal torticollis of infancy, hemiplegia

Interaction:
β4 subunit CACNB4, α2δ subunits, calmodulin, CaBP1, VILIP, mint, CASK, Syntaxin, SNAP25

Modulator:
Kuratoxin, ω-agatoxin IIIA, ω-conotoxin MVIIC, ω-agatoxin-IVA, roscovitine

Assays:
Patch Clamp: whole cell, room temperature

Particularities:
Ca_V 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

Respiratory Chain Complex II and III - Current Traces

Icon N1 SURFE²R N1 data and applications:

Respiratory Chain Complex II is a succinate dehydrogenase. In this complex, succinate is oxidated to fumarate. The electrons are transfered to the quinone pool, the Complex III (cytochrome bc₁ complex) and cytochrome c, while four protons are transported to the intermembrane space.

a. P-bond hydrolysis driven transporters