any opinions on dual trafficking of mitochondrial associated proteins ??
Hey! Sorry, I do not know the answer to that, but I also want to know that..!
my opinion is yes-- when I was working with nuclear hormone receptor ERbeta, I found it in the mitochondria. It is also believed to be in the membrane as well as established to function in the nucleus. However, no one has looked to see if ERbeta is processed through the endomembrane pathway (if membrane bound), as well as to the mitochondria. So using protein markers for the endmembrane pathway we found that ERbeta was associating with ER ribosomal protein L7a which would indicate endomembrane pathway-this makes sense if ERbeta was acting as membrane receptor. As to the mitochondria, we found it interacting with TOM20, a mitochondrial receptor --With so many organelle markers, and labeling combined with live cell imaging, we need to do more trafficking studies of similar by-functional proteins.
I believe we will find other proteins previously identified as nuclear that are also identified as mitochondrial (like p53) --we know there is a synergy of function between nuclear and mitochondria-- Several hormones receptor know to act in the nucleus are acting in the mitochondria and probably do so synergistically --as we learn more about mitochondrial proteins and mitochondrial function, I believe we will find this to be true for alot more previously identified nuclear proteins. One in particular is nuclear hTERT, it has also been identified in the mitochondria.
what do you think???