Targeting signals in peroxisomal membrane proteins.
Peroxisomal membrane proteins (PMPs) are encoded by the nuclear genome and translated on cytoplasmic ribosomes. Newly synthesized PMPs can be targeted directly from the cytoplasm to peroxisomes or travel to peroxisomes via the endoplasmic reticulum (ER). The mechanisms responsible for the targeting of these proteins to the peroxisomal membrane are still rather poorly understood. However, it is clear that the trafficking of PMPs to peroxisomes depends on the presence of cis-acting targeting signals, called mPTSs. These mPTSs show great variability both in the identity and number of requisite residues. An emerging view is that mPTSs consist of at least two functionally distinct domains: a targeting element, which directs the newly synthesized PMP from the cytoplasm to its target membrane, and a membrane-anchoring sequence, which is required for the permanent insertion of the protein into the peroxisomal membrane. In this review, we summarize our knowledge of the mPTSs currently identified.
Van Ael
Elke
E
Katholieke Universiteit Leuven, Faculty of Medicine, Department of Molecular Cell Biology, Division of Pharmacology, Campus Gasthuisberg, Herestraat 49 bus 601, 3000 Leuven, Belgium.
Fransen
Marc
M
D000595:Amino Acid Sequence; D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D019143:Evolution, Molecular; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D020675:Peroxisomes / Q000378:metabolism*; D011485:Protein Binding; D021382:Protein Sorting Signals; D021381:Protein Transport
D008565:Membrane Proteins; D021382:Protein Sorting Signals