Peroxisomes: offshoots of the ER

Peroxisomes are part of the ubiquitous set of eukaryotic organelles. They are small, single membrane bounded vesicles, specialized in the degradation of very-long-chain fatty acids and in synthesis of myelin lipids. Once considered inconspicuous, recent new insights in the formation and function of peroxisomes have revealed a much more subtle interplay between organelles that warrant a re-evaluation of the historical assignment of peroxisomes as being either autonomous or ER-derived. Peroxisomes acquire their lipids and membrane proteins from the ER, whereas they import their matrix proteins directly from the cytosol. Remarkably, many of its metabolic enzymes and factors controlling peroxisome abundance (fission and inheritance) too are shared with other organelles, stressing interdependence among cellular compartments.