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Mitochondrial uncoupling protein 3 (UCP3) is a members of the larger family of mitochondrial anion carrier proteins (MACP). UCPs facilitate the transfer of anions from the inner to the outer mitochondrial membrane and transfer of protons from the outer to the inner mitochondrial membrane, reducing the mitochondrial membrane potential in mammalian cells.
In essence, the Goldman formula expresses the membrane potential as a weighted average of the reversal potentials for the individual ion types, weighted by permeability. (Although the membrane potential changes about 100 mV during an action potential, the concentrations of ions inside and outside the cell do not change significantly.
Most often, the threshold potential is a membrane potential value between –50 and –55 mV, [1] but can vary based upon several factors. A neuron's resting membrane potential (–70 mV) can be altered to either increase or decrease likelihood of reaching threshold via sodium and potassium ions.
Depolarization is the process by which the membrane potential becomes less negative, facilitating the generation of an action potential. [6] For this rapid change to take place within the interior of the cell, several events must occur along the plasma membrane of the cell.
The protons are pumped from the mitochondrial matrix to the IMS by these respiratory complexes. As a result, an electrochemical gradient is generated, which is combined by forces due to a H + gradient (pH gradient) and a voltage gradient (membrane potential). The pH in the IMS is about 0.7 unit lower than the one in the matrix and the membrane ...
[1] [2] There is debate as to whether or not this channel is expressed in the cell surface membrane. [3] [4] [5] This major protein of the outer mitochondrial membrane of eukaryotes forms a voltage-dependent anion-selective channel (VDAC) that behaves as a general diffusion pore for small hydrophilic molecules.
The inner mitochondrial membrane is compartmentalized into numerous folds called cristae, which expand the surface area of the inner mitochondrial membrane, enhancing its ability to produce ATP. For typical liver mitochondria, the area of the inner membrane is about five times as large as that of the outer membrane.
It can be described as the measure of the potential energy stored (chemiosmotic potential) as a combination of proton and voltage (electrical potential) gradients across a membrane. The electrical gradient is a consequence of the charge separation across the membrane (when the protons H + move without a counterion, such as chloride Cl −).