TRPM6 TRPM7 of Magnesium transporters
The investigation of the TRPM genes and proteins in human cells is an area of intense recent study and, at times, debate. Montell et al. (2002)[72] have reviewed the research into the TRP genes, and a second review by Montell (2003)[73] has reviewed the research into the TRPM genes.
The TRPM family of ion channels has members throughout the metazoa. The TRPM6 and TRPM7 proteins are highly unusual, containing both an ion channel domain and a kinase domain (Figure 1.7). The role of the kinase domain brings about the most heated debate[73].
The activity of these two proteins has been very difficult to quantify. TRPM7 by itself appears to be a Ca2+ channel[74] but in the presence of TRPM6 the affinity series of transported cations places Mg2+ above Ca2+.[9][75] The differences in reported conductance were caused by the expression patterns of these genes. TRPM7 is expressed in all cell types tested so far, while TRPM6 shows a more restricted pattern of expression[76]. An unfortunate choice of experimental system by Voets et al., (2004)[77] led to the conclusion that TRPM6 is a functional Mg2+ transporter. However, later work by Chubanov et al. (2004)[76] clearly showed that TRPM7 is required for TRPM6 activity, and that the results of Voets et al. are explained by the expression of TRPM7 in the experimental cell line used by Voets et al. in their experiments. Whether TRPM6 is functional by itself is yet to be determined.
Tags: Integral membrane proteins, Ion channels, Membrane proteins, Proteins, Transmembrane proteins
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Among the functional responsibilities of the TRPM channels are:
regulation of calcium oscillations after T cell activation (TRPM4).[6]
sensory transduction in taste cells (TRPM5).
regulation of magnesium reabsorption in the kidneys and absorption in the intestines (TRPM6).[7]
regulation of cell adhesion (TRPM7).
TRPM6 is a transient receptor potential ion channel associated with hypomagnesemia with secondary hypocalcemia.[1]
TRPM is a family of transient receptor potential ion channels where the "M" stands for "melastatin".[1] Functional TRPM channels are believed to form tetramers.[2]
Unlike the TRPC and TRPV sub-families, TRPM subunits do not contain N-terminal ankyrin repeat motifs but, rather, contain entire functional proteins in their C-termini. TRPM6 and TRPM7, for example, contain functional ?-kinase segments, which are a type of serine/threonine-specific protein kinase.
All forms of life require magnesium, and yet the molecular mechanisms of Mg2+ uptake from the environment and the distribution (transport) of this vital element within the organism are only slowly being elucidated. In bacteria Mg2+ is probably mainly supplied by the CorA protein[1] and, where the CorA protein is absent, by the MgtE protein[2][3]. In yeast the initial uptake is via the Alr1p and Alr2p proteins[4], but at this stage the only internal Mg2+ distributing protein identified is Mrs2p[5]. Within the protozoa only one Mg2+ transporter (XntAp) has been identified[6]. In metazoa, Mrs2p[7] and MgtE homologues[8] have been identified,
The Mg2+ cation is the second most abundant cation in seawater (occurring at about 12% of the mass of sodium there), which makes seawater and sea-salt an attractive commercial source of Mg. To extract the magnesium, calcium carbonate is added to sea water to form magnesium carbonate precipitate.
MgCl2 + CaCO3 ? MgCO3 + CaCl2
Magnesium carbonate is insoluble in water so it can be filtered out, and reacted with hydrochloric acid to obtain concentrated magnesium chloride.
MgCO3 + 2HCl ? MgCl2 + CO2 + H2O
From magnesium chloride, electrolysis produces magnesium.
See also: Category:Magnesium minerals
There are two classes of glutamate transporters, those that are dependent on an electrochemical gradient of sodium ions (the EAATs) and those that are not (VGluTs).[5] Some sodium independent transporters such as the cystein-glutamate antiporter are localised to plasma membrane of cells whilst others the are called vesicular transporters. Na+-dependent transporters are actually also dependent on K+ concentrations, and so are also known as 'sodium and potassium coupled glutamate transporters' or, in humans, 'excitatory amino acid transporters' (EAATs).[6] Some Na+-dependent transporters have also been called 'high-affinity transporters', though their glutamate affinity actually varies widely.[6]
mitochondria also possess mechanisms for taking up
The magnesium ion is necessary for all life (see magnesium in biology), so magnesium salts are an additive for foods, fertilizers (Mg is a component of chlorophyll), and culture media.
Magnesium hydroxide is used in milk of magnesia, its chloride, oxide, gluconate, malate, orotate and citrate used as oral magnesium supplements, and its sulfate (Epsom salts) for various purposes in medicine, and elsewhere (see the article for more). Oral magnesium supplements have been claimed to be therapeutic for some individuals who suffer from Restless Leg Syndrome (RLS).[citation needed]
Magnesium borate, magnesium salicylate and magnesium sulfate are used as antiseptics.
Magnesium bromide is used
In enzymology, a magnesium protoporphyrin IX methyltransferase (EC 2.1.1.11) is an enzyme that catalyzes the chemical reaction
S-adenosyl-L-methionine + magnesium protoporphyrin IX S-adenosyl-L-homocysteine + magnesium protoporphyrin IX 13-methyl ester
Thus, the two substrates of this enzyme are S-adenosyl methionine and magnesium protoporphyrin IX, whereas its two products are S-adenosylhomocysteine and magnesium protoporphyrin IX 13-methyl ester.
This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:magnesium-protoporphyrin-IX O-methyltransferase. This enzyme participates in porphyrin and chlorophyll metabolism.
In enzymology, a magnesium chelatase (EC 6.6.1.1) is an enzyme that catalyzes the chemical reaction
ATP + protoporphyrin IX + Mg2+ + H2O ADP + phosphate + Mg-protoporphyrin IX + 2 H+
The 4 substrates of this enzyme are ATP, protoporphyrin IX, Mg2+, and H2O, whereas its 4 products are ADP, phosphate, Mg-protoporphyrin IX, and H+.
This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes. The systematic name of this enzyme class is Mg-protoporphyrin IX magnesium-lyase. Other names in common use include protoporphyrin IX magnesium-chelatase, protoporphyrin IX Mg-chelatase, magnesium-protoporphyrin IX chelatase, magnesium-protoporphyrin chelatase, magnesium-chelatase, Mg-chelatase,
Magnesium metal and alloys are highly flammable in their pure form when molten, as a powder, or in ribbon form. Burning or molten magnesium metal reacts violently with water. Magnesium powder is an explosive hazard. One should wear safety glasses while working with magnesium, and if burning it, these should include a heavy U.V. filter, similar to welding eye protection. The bright white light (including ultraviolet) produced by burning magnesium can permanently damage the retinas of the eyes, similar to welding arc burns.[16]
Water should not be used to extinguish magnesium fires, because it can produce hydrogen which will feed the
Transient receptor potential cation channel, subfamily M, member 7, also known as TRPM7, is a human gene encoding a protein of the same name.
TRPs, mammalian homologs of the Drosophila transient receptor potential (trp) protein, are ion channels that are thought to mediate capacitative calcium entry into the cell. TRP-PLIK is a protein that is both an ion channel and a kinase. As a channel, it conducts calcium and monovalent cations to depolarize cells and increase intracellular calcium. As a kinase, it is capable of phosphorylating itself and other substrates. The kinase activity is necessary for channel function, as shown by
Magnesium (pronounced /mæg?ni?zi?m/) is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.
Magnesium, an alkaline earth metal, is the ninth most abundant element in the universe by mass.[1] It constitutes about 2% of the Earth's crust by mass, which makes it the eighth most abundant element in the crust.[2] It is the third most abundant element dissolved in seawater.[citation needed]
Magnesium is the 11th most abundant element by mass in the human body; its ions are essential to all living cells, but nearly 50% is found within the bones.[citation needed] The free
Specific types of neurotransmitter transporters include the following:
GABA transporters, including:
GABA transporter type 1 (GAT-1)
GABA transporter type 2 (GAT-2)
GABA transporter type 3 (GAT-3)
Betaine transporter (BGT-1)
Vesicular GABA transporter (VGAT)
Glutamate transporters
Glutamine transporters[5]
Glycine transporters, including:
Glycine transporter type 1 (GlyT-1)
Glycine transporter type 2 (GlyT-2)
Monoamine transporters including:
The dopamine transporter, DAT.
The norepinephrine transporter, NET.
The serotonin transporter, SERT.
Vesicular acetylcholine transporters[6]
Vesicular monoamine transporters
Excitatory Amino Acid Transporters (EAAT), formerly known as Glutamate transporters, belong to the family of neurotransmitter transporters. They serve to terminate the excitatory neurotransmitter signal by removal (uptake) of glutamate from the neuronal synapse into Glia cells.
In details, the EAATs are membrane-bound pumps that resemble ion channels.[1] These transporters play the important role of regulating concentrations of glutamate in the extracellular space, keeping it at low levels.[2] After glutamate is released as the result of an action potential, glutamate transporters quickly remove it from the extracellular space to keep its levels low, thereby terminating the synaptic transmission.[1][3]
Without the activity of
ATP-binding domain of ABC transporters is a water-soluble domain of transmembrane ABC transporters.
ABC transporters belong to the ATP-Binding Cassette superfamily, which uses the hydrolysis of ATP to translocate a variety of compounds across biological membranes. ABC transporters are minimally constituted of two conserved regions: a highly conserved ATP binding cassette (ABC) and a less conserved transmembrane domain (TMD). These regions can be found on the same protein or on two different ones. Most ABC transporters function as a dimer and therefore are constituted of four domains, two ABC modules and two TMDs.
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