Pseudo half-molecules of the ABC transporter, COMATOSE, bind Pex19 and target to peroxisomes independently but are both required for activity.
Peroxisomal ABC transporters of animals and fungi are "half-size" proteins which dimerise to form a functional transporter. However, peroxisomal ABC transporters of land plants are synthesised as a single polypeptide which represents a fused heterodimer. The N- and C-terminal pseudo-halves of COMATOSE (CTS; AtABCD1) were expressed as separate polypeptides which bound Pex19 in vitro and targeted independently to the peroxisome membrane in yeast, where they were stable but not functional. When co-expressed, the pseudo-halves were fully functional as indicated by ATPase activity and rescue of the pxa1pxa2Δ mutant for growth on oleate. The functional significance of heterodimer asymmetry is discussed.
Centre for Plant Sciences, Irene Manton Building, University of Leeds, Leeds LS2 9JT, UK.
Yvonne
Y
Nyathi
Xuebin
X
Zhang
Jocelyn M
JM
Baldwin
Kristin
K
Bernhardt
Barbara
B
Johnson
Stephen A
SA
Baldwin
Frederica L
FL
Theodoulou
Alison
A
Baker
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000737:chemistry; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites; D019281:Dimerization; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019301:Oleic Acid / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D020675:Peroxisomes / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; D008565:Membrane Proteins; C514419:PEX19 protein, Arabidopsis; D010455:Peptides; D020033:Protein Isoforms; D019301:Oleic Acid; D000251:Adenosine Triphosphatases; C456843:At4g39850 protein, Arabidopsis