Sandbox Reserved 1601: Difference between revisions

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==Regulation and Inhibition==
==Regulation and Inhibition==


The most well-known and commonly used inhibitor of calcium uptake into the mitochondria is ruthenium red (RuRed).  RuRed effectively inhibits calcium uptake without affecting mitochondrial respiration or calcium efflux.  Additionally, it has been shown to mitigate tissue damage due to IRI and slow cancer cell migration. The issue with RuRed is that its purification has always been a challenging matter.<ref name="Woods"/> Interestingly enough, this led to even more developments in the search for an inhibitor.  Many scientists had observed that impure RuRed actually had greater inhibition than pure RuRed.  One of the common minor impurities of RuRed, Ru360, was found to be the active component of the RuRed mixtures, meaning it responsible for calcium inhibition. Ru360 is now commercially available and has been widely used for the study of calcium-dependent cellular processes and as a therapeutic agent. Very little is known about its mechanism of inhibtion, but studies show that it interacts with the DXXE motif of the loop connecting the TM1 and TM2 helices.<ref name="Woods" />
The most well-known and commonly used inhibitor of the MCU is ruthenium red (RuRed).<ref name="Woods"/> RuRed is a trinuclear, oxo-bridged complex that effectively inhibits calcium uptake without affecting mitochondrial respiration or calcium efflux.<ref name="Woods"/> The disadvantage of ruthenium red is its challenging purification.<ref name="Woods"/> Interestingly, an impure version of RuRed, termed Ru360, was found to be the active component of RuRed and thus another good inhibitor of the MCU.<ref name="Woods"/> Ru360 is a binuclear, oxo-bridged complex with a similar structure to that of RuRed.<ref name="Woods"/> The only flaw with Ru360 was that it showed low cell permeability, so Ru265 was developed and had twice the cell permeability of Ru360.<ref name="Woods"/> Ru265 possesses two bridged Ru centers bridged by a nitride ligand.<ref name="Woods"/>


Ru360 was a very successful inhibitor, but it showed low cell permeability.  So, a new inhibitor called Ru265 was developed which could be easily synthesized and didn't need chromatographic purification.  Ru265 had all of the benefits of Ru360, with with twice the cell permeability. Additionally, the same mutations didn't seem to affect it. Mutations of D261 and S259 in human MCU reduced inhibitory effect of Ru360, but not Ru265. Additionally,  there were other mutations that affected Ru265, but not Ru360.<ref name="Woods" /> This shows how much more research is needed before a mechanism is understood for any inhibitor of the MCU.
Recent experiments suggest that Ru360 inhibits calcium uptake through interactions with the WDXXEP motif.<ref name="Woods"/> However, not much is actually known about the method of inhibition. Mutations of Asp261 and Ser259 in human MCU (analogous to Asp225 and Ser223 in ''C. europaea'') were shown to maintain calcium uptake into the matrix, but reduce the inhibitory effect of Ru360.<ref name="Woods"/> Curiously, the same Ser259 mutation did not affect inhibition of Ru265.<ref name="Woods"/> Additionally, a mutation in a cysteine residue in the NTD reduced the inhibitory effects of Ru265, but not Ru360.<ref name="Woods"/> So, while various inhibitors for the MCU are known, the mechanism of each is still largely unknown.
 
This is a sample scene created with SAT to <scene name="/12/3456/Sample/1">color</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.


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</StructureSection>
==References==
==References==
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