Import of proteins into peroxisomes: piggybacking to a new home away from home |
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Authors: | Sven Thoms |
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Affiliation: | Department of Child and Adolescent Medicine, University Medical Center, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany |
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Abstract: | Peroxisomes are capable of importing folded and oligomeric proteins. However, it is a matter of dispute whether oligomer import by peroxisomes is the exception or the rule. Here, I argue for a clear distinction between homo-oligomeric proteins that are essentially peroxisomal, and dually localized hetero-oligomers that access the peroxisome by piggyback import, localizing there in limited number, whereas the majority remain in the cytosol. Homo-oligomeric proteins comprise the majority of all peroxisomal matrix proteins. There is evidence that binding by Pex5 in the cytosol can regulate their oligomerization state before import. The hetero-oligomer group is made up of superoxide dismutase and lactate dehydrogenase. These proteins have evolved mechanisms that render import inefficient and retain the majority of proteins in the cytosol. |
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Keywords: | peroxisome protein import cellular organelles piggyback import Pex5 PTS1 |
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