Toward understanding plant peroxisome proliferation

Plant peroxisomes are highly dynamic organelles that adapt to environmental variation by altering their number, but the molecular basis for plant peroxisome proliferation is largely unknown. To begin understanding how this fundamental cell biological process is controlled in plants, we recently characterized the Arabidopsis homologues of the yeast Pex11p protein, which is involved in peroxisome proliferation via an unknown mechanism. Using a combination of fluorescence microscopy, immunobiochemistry, overexpression and loss-of-function studies, and heterologous gene expression in yeast cells, we showed that all five Arabidopsis PEX11 proteins target to peroxisomal membranes and promote peroxisome proliferation with partial redundancy and specificity. A subset of the dynamin-related proteins (DRPs) is also involved with peroxisome division in plants, yeast, and mammals. Future experiments should focus on addressing the biochemical function of PEX11 and using new tools to uncover additional components of the peroxisome proliferation pathways, especially those that are unique to plants.