Although they are present almost everywhere, on land and sea, a group of related bacteria in the superphylum Planctomycetes-Verrucomicrobia-Chlamydiae, or PVC, have remained in relative obscurity ever since they were first described about a decade ago. Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, have discovered that these poorly-studied bacteria possess proteins thought to exist only in eukaryotes -- organisms whose cells have a nucleus.
Their findings, featured on the cover of the January 20 edition of PLoS Biology, could help to unravel part of the evolutionary history of eukaryotic cells such as our own.
In eukaryotes, the endomembrane system is a network of membrane-bound compartments which stores and transports material within the cell. These compartments, which include organelles such as the endoplasmic reticulum and the Golgi complex, also exchange portions of membrane with each other, by forming and absorbing vesicles. Scientists believed that membrane-bound compartments were unique to eukaryotic cells, and that membrane-coat proteins, which have a unique architecture and are associated with the endomembrane system, existed only in eukaryotes. Recently, however, membrane-bound compartments were observed in PVC bacteria.
Their findings, featured on the cover of the January 20 edition of PLoS Biology, could help to unravel part of the evolutionary history of eukaryotic cells such as our own.
In eukaryotes, the endomembrane system is a network of membrane-bound compartments which stores and transports material within the cell. These compartments, which include organelles such as the endoplasmic reticulum and the Golgi complex, also exchange portions of membrane with each other, by forming and absorbing vesicles. Scientists believed that membrane-bound compartments were unique to eukaryotic cells, and that membrane-coat proteins, which have a unique architecture and are associated with the endomembrane system, existed only in eukaryotes. Recently, however, membrane-bound compartments were observed in PVC bacteria.
