1 Identification of a new fatty acid synthesis-transport machinery at the peroxisomal membrane § Merle Hillebrand 1,5 , Søren W. Gersting 2,5 , Amelie S. Lotz-Havla 2 , Annika Schäfer 3 , Hendrik Rosewich 1 , Oliver Valerius 4 , Ania C. Muntau 2 , Jutta Gärtner 1* From the 1 Department of Pediatrics and Pediatric Neurology, Georg August University, Faculty of Medicine, 37075 Göttingen, Germany, the 2 Department of Molecular Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany, the 3 Department of Dermatology, Venereology, and Allergology, Georg August University, Faculty of Medicine, 37075 Göttingen, Germany and the 4 Institute of Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg August University, 37077 Göttingen, Germany 5 These authors contributed equally to this work Running Title: New fatty acid synthesis-transport machinery § This work was supported by the Deutsche Forschungsgemeinschaft (GA354/7-1) to J.G. and the Bavarian Genome Research Network (BayGene) and the LMUexcellent grant 42595-6 to A.C.M. * To whom correspondence should be addressed: Tel: +49-551-398035; Fax: +49-551-396252; E- mail: gaertnj@med.uni-goettingen.de The abbreviations used are: ACLY, ATP citrate lyase; ALDP, adrenoleukodystrophy protein; BRET, bioluminescence resonance energy transfer; FASN, fatty acid synthase; ACC, Acetyl-CoA carboxylase; LCFA, long chain fatty acid; PPI, protein-protein interactions; VLCFA, very long chain fatty acid; X-ALD, X-linked adrenoleukodystrophy Background: Dysfunction of the peroxisomal ABC-transporter ALDP and elevated very long chain fatty acids are the hallmark of X-ALD. Results: Peroxisomal ABC-transporters interact with proteins functioning in fatty acid synthesis and activation. Conclusion: We identified a new fatty acid synthesis-transport machinery adapted to different chain lengths and metabolic conditions. Significance: This machinery extends the knowledge on peroxisomal β- oxidation and X- ALD pathogenesis. The neurodegenerative disease X-linked adrenoleukodystrophy (X-ALD) is characterized by the abnormal accumulation of very long chain fatty acids (VLCFAs). Mutations in the gene encoding the peroxisomal ABC half-transporter adrenoleukodystrophy protein (ALDP) are the primary cause of X-ALD. To gain a better understanding of ALDP dysfunction, we searched for interaction partners of ALDP and identified binary interactions to proteins with functions in fatty acid synthesis (ACLY, FASN, ACC) and activation (FATP4), constituting a so far unknown fatty acid synthesis-transport machinery at the cytoplasmic side of the peroxisomal membrane. This machinery adds knowledge to the complex mechanisms of peroxisomal fatty acid metabolism at a molecular level and elucidates potential epigenetic mechanisms as regulatory processes in the pathogenesis and thus the clinical course of X-ALD. INTRODUCTION The adrenoleukodystrophy protein (ALDP, ABCD1) belongs to the ATP-binding cassette (ABC) transporter protein family. Besides PMP70 (ABCD3) and ALDR (ABCD2) it is one of three ABC half-transporters residing in the peroxisomal membrane of mammals (1-4). ALDP has a pivotal role in peroxisome function since mutations in the ABCD1 gene encoding ALDP are responsible for the most common inherited peroxisomal disorder X- linked adrenoleukodystrophy (X-ALD). This complex and devastating neurodegenerative disorder is characterized by the abnormal accumulation of saturated very long chain fatty acids (VLCFAs) especially in brain white matter, adrenal cortex and testis (5-7). To date, 567 pathogenic ABCD1 mutations are known, 357 of these are missense (HGMD database, www.hgmd.org). They are distributed throughout the gene without a mutational http://www.jbc.org/cgi/doi/10.1074/jbc.M111.272732 The latest version is at JBC Papers in Press. Published on November 1, 2011 as Manuscript M111.272732 Copyright 2011 by The American Society for Biochemistry and Molecular Biology, Inc. by guest, on November 5, 2011 www.jbc.org Downloaded from