The importomer—A peroxisomal membrane complex involved in protein translocation into the peroxisome matrix

The import of proteins into the peroxisome matrix is an essential step in peroxisome biogenesis, which is critical for normal functioning of most eukaryotic cells. The translocation of proteins across the peroxisome membrane and the dynamic behavior of the import receptors during the import cycle is facilitated by several peroxisome–membrane-associated protein complexes, one of which is called the importomer complex [B. Agne, N.M. Meindl, K. Niederhoff, H. Einwachter, P. Rehling, A. Sickmann, H.E. Meyer, W. Girzalsky, W.H. Kunau, Pex8p: an intraperoxisomal organizer of the peroxisomal import machinery, Mol. Cell 11 (2003) 635–646; P.P. Hazra, I. Suriapranata, W.B. Snyder, S. Subramani, Peroxisome remnants in pex3Δ cells and the requirement of Pex3p for interactions between the peroxisomal docking and translocation subcomplexes, Traffic 3 (2002) 560–574. [1] and [2]]. We provide below a brief historical perspective regarding the importomer and its role in peroxisome biogenesis. We also identify areas in which further work is needed to uncover the physiological role of the importomer.