6533b826fe1ef96bd128492a

RESEARCH PRODUCT

Structure-function analysis of peroxisomal ATP-binding cassette transporters using chimeric dimers

Christine ArnouldCatherine GondcailleRonald J.a. WandersTatiana LopezCarlo W.t. Van RoermundFlore GeillonDoriane TrompierJean-paul Pais De BarrosSoëli CharbonnierAlexandre M.m. DiasStéphane Savary

subject

[SDV.BA] Life Sciences [q-bio]/Animal biologyprotéine chimereanimal diseasesATP-binding cassette transporterProximity ligation assayProtein Chimerabiochimie structurale[ SDV.BA ] Life Sciences [q-bio]/Animal biologyPolymerase Chain ReactionBiochemistryGreen fluorescent proteininteraction moléculaireMice[ CHIM.OTHE ] Chemical Sciences/Otherhomodimèrereproductive and urinary physiologyAnimal biologyhétérodimèrechemistry.chemical_classification[SDV.BA]Life Sciences [q-bio]/Animal biologymammifèreTransfectionPeroxisomeprotéine de fusionBiochemistry[CHIM.OTHE] Chemical Sciences/OtherDimerizationPlasmidsABC Transporter;Fatty Acid;Peroxisome;Protein Chimera;Protein-Protein Interactiontransporteur abcBiologyPeroxisomeCell LineProtein–protein interactionStructure-Activity RelationshipMembrane BiologyBiologie animaleparasitic diseasesAutre (Chimie)PeroxisomesAnimalsHumansMolecular BiologyDNA PrimersBase SequenceABCD2fungiABCD1Fatty acidCell BiologyFusion proteinRatsProtein-Protein InteractionABC TransporterchemistryATP-Binding Cassette TransportersOther[CHIM.OTHE]Chemical Sciences/OtherFatty Acid

description

Background: Peroxisomal ABC transporters are predicted to function as homodimers in mammals. [br/] Results: ABCD1 interacts with ABCD2. Chimeric proteins mimicking full-length dimers represent novel tools for functional study. Artificial homodimers and heterodimers are functional. [br/] Conclusion: Interchangeability between ABCD1 and ABCD2 is confirmed, but PUFA transport depends on ABCD2. [br/] Significance: For the first time, heterodimers in mammals are proven to be functional.[br/] ABCD1 and ABCD2 are two closely related ATP-binding cassette half-transporters predicted to homodimerize and form peroxisomal importers for fatty acyl-CoAs. Available evidence has shown that ABCD1 and ABCD2 display a distinct but overlapping substrate specificity, although much remains to be learned in this respect as well as in their capability to form functional heterodimers. Using a cell model expressing an ABCD2-EGFP fusion protein, we first demonstrated by proximity ligation assay and co-immunoprecipitation assay that ABCD1 interacts with ABCD2. Next, we tested in the pxa1/pxa2 yeast mutant the functionality of ABCD1/ABCD2 dimers by expressing chimeric proteins mimicking homo- or heterodimers. For further structure-function analysis of ABCD1/ABCD2 dimers, we expressed chimeric dimers fused to enhanced GFP in human skin fibroblasts of X-linked adrenoleukodystrophy patients. These cells are devoid of ABCD1 and accumulate very long-chain fatty acids (C26:0 and C26:1). We checked that the chimeric proteins were correctly expressed and targeted to the peroxisomes. Very long-chain fatty acid levels were partially restored in transfected X-linked adrenoleukodystrophy fibroblasts regardless of the chimeric construct used, thus demonstrating functionality of both homo- and heterodimers. Interestingly, the level of C24:6 n-3, the immediate precursor of docosahexaenoic acid, was decreased in cells expressing chimeric proteins containing at least one ABCD2 moiety. Our data demonstrate for the first time that both homo- and heterodimers of ABCD1 and ABCD2 are functionally active. Interestingly, the role of ABCD2 (in homo- and heterodimeric forms) in the metabolism of polyunsaturated fatty acids is clearly evidenced, and the chimeric dimers provide a novel tool to study substrate specificity of peroxisomal ATP-binding cassette transporters.

https://hal.archives-ouvertes.fr/hal-01223550