Identification and functional reconstitution of the yeast peroxisomal adenine nucleotide transporter

Abstract

The requirement for small molecule transport systems across the peroxisomal membrane has previously been postulated, but not directly proven. Here we report the identification and functional reconstitution of Ant1p (Ypr128cp), a peroxisomal transporter in the yeast Saccharomyces cerevisiae, which has the characteristic sequence features of the mitochondrial carrier family. Ant1p was found to be an integral protein of the peroxisomal membrane and expression of ANT1 was oleic acid inducible. Targeting of Ant1p to peroxisomes was dependent on Pex3p and Pex19p, two peroxins specifically required for peroxisomal membrane protein insertion. Ant1p was essential for growth on medium-chain fatty acids as the sole carbon source. Upon reconstitution of the overexpressed and purified protein into liposomes, specific transport of adenine nucleotides could be demonstrated. Remarkably, both the substrate and inhibitor specificity differed from those of the mitochondrial ADP/ATP transporter. The physiological role of Ant1p in S.cerevisiae is probably to transport cytoplasmic ATP into the peroxisomal lumen in exchange for AMP generated in the activation of fatty acids.

Molecular Identification and Functional Characterization of Arabidopsis thaliana Mitochondrial and Chloroplastic NAD+ Carrier Proteins

“…However, today we know that the presence of MCF proteins is by no means restricted to mitochondrial membranes (51). The recent discovery of MCF-type nucleotide transporters in peroxisomes (7,18,52), plant plastids (19,20,23), and the endoplasmic reticulum of Arabidopsis (21) strikingly demonstrates that several organelles, especially in plant cells, exploit the large pool of MCF proteins to facilitate cross-membrane nucleotide transport. Thus, with our observation that AtNDT1-GFP resides in the chloroplast envelope (Fig.…”

“…The most prominent member is the mitochondrial ADP/ATP carrier AAC (4), but MCF-type nucleotide transporters have also been identified in peroxisomes (7,18), in plastids (19,20), and in the endoplasmic reticulum of higher plants (21). The transport modes catalyzed by MCF-type adenylate nucleotide transporters range from typical ADP/ATP counterexchange in mitochondria (4) to ATP/AMP exchange in peroxisomes (7,18) and in Arabidopsis mitochondria (22) range from ADP-glucose/ADP exchange in maize endosperm amyloplasts (23) to unidirectional adenylate export from plastids (20,23).…”

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

“…Recently, another MCF member was demonstrated to function as a plastidic folate transporter (Bedhomme et al, 2005), and other MCF members have been shown to be involved in adenine nucleotide uniport into plastids (Leroch et al, 2005) and in the uptake of ADP-glucose into maize (Zea mays) endosperm plastids (Sullivan and Kaneko, 1995). Moreover, a yeast peroxisomal ATP transporter also belongs to the MCF (Palmieri et al, 2001), (E) RT-PCR analysis of the transcript level of Nb SAMT1. Primers annealing outside of the TTO-Nb SAMT1 construct were used.…”

Catabolism of hydroxyacids and biotechnological production of lactones by Yarrowia lipolytica

“…However, more recent works suggest that, in vivo, the membrane is rather impermeable to NAD(H) and acetyl-CoA . ATP for its part has been shown to enter the peroxisomal lumen through the action of a transporter (Palmieri et al 2001), in the absence of which medium-chain (but not long-chain) fatty acids could not be activated into acyl-CoA (Van Roermund et al 2001). …”