Bacterial actins? An evolutionary perspective.
According to the conventional wisdom, the existence of a cytoskeleton in eukaryotes and its absence in prokaryotes constitute a fundamental divide between the two domains of life. An integral part of the dogma is that a cytoskeleton enabled an early eukaryote to feed upon prokaryotes, a consequence of which was the occasional endosymbiosis and the eventual evolution of organelles. Two recent papers1, 2 present compelling evidence that actin, one of the principal components of a cytoskeleton, has a homolog in Bacteria that behaves in many ways like eukaryotic actin. Sequence comparisons reveal that eukaryotic actin and the bacterialhomolog (mreB protein), unlike many other proteins common to eukaryotes and Bacteria, have very different and more highly extended evolutionary histories.
Doolittle
Russell F
RF
Center for Molecular Genetics, University of California, San Diego, La Jolla 92093-0634, USA. rdoolittle@ucsd.edu
York
Amanda L
AL
D000199:Actins / Q000235:genetics*; D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D001419:Bacteria / Q000235:genetics*; D005075:Biological Evolution; D017124:Conserved Sequence; D004265:DNA Helicases / Q000235:genetics; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics; D018745:Genome, Plant; D008322:Mammals; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
D000199:Actins; D029681:Arabidopsis Proteins; C118957:DDM1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D004265:DNA Helicases