Peroxisomal ABC transporters.

The set of proteins found in the membranes of mammalian peroxisomes includes four half ABC transporters (ALDP, ALDR, PMP70, P70R) comprising a distinct subset of the superfamily of ABC transporters designated subfamily D. Each has an N-terminal hydrophobic transmembrane domain with multiple transmembrane segments (TMS) and a hydrophilic C-terminal half containing a nucleotide-binding domain (NBD) with Walker A and B motifs. Limited topology studies indicate that the C-terminal hydrophilic halves of ALDP and PMP70 extend into the cytosol (Contreras et al., 1996; Kamijo et al., 1990). To provide context in what follows, we first briefly review peroxisome function, genetic diseases and biogenesis; we then focus on the molecular, cellular and evolutionary biology of the mammalian peroxisomal ABC transporters.