Molecular characteristics

TMEM126B is a mitochondrial protein, involved in energy exchange for the cell. The information to make the TMEM126B protein is contained in specific DNA. Variations or “spelling mistakes” in the DNA code for TMEM126B will mean that this protein will not work properly and energy exchange will be impaired. The spelling mistakes known to occur in TMEM126B all seem to have very severe consequences for the remainder of the encoded DNA and, as a result, the TMEM126B protein is not properly formed and quickly decays. Effectively this means that there is no functioning TMEM126B protein available to assemble the complex I enzyme and energy exchange is impaired. Sometimes the spelling mistake can be an omission of a letter in the code, changing how the remainder of the DNA is read. In other cases, a substitution of one letter for another affects a specific part of the TMEM126B protein making it unstable. This is a bit like baking – all the ingredients, the oven and the baker need to be available and used correctly to make a successful cake. For successful assembly of complex I all the different subunits are required (there are over 40 of them) and at least 15 different proteins involved in putting them together. TMEM126B is just one part of the puzzle, but each piece is very important.