Ceramide regulates interaction of Hsd17b4 with Pex5 and function of peroxisomes

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids 2019-10, Vol.1864 (10), p.1514-1524
• Main Authors: Zhu, Zhihui, Chen, Jianzhong, Wang, Guanghu, Elsherbini, Ahmed, Zhong, Liansheng, Jiang, Xue, Qin, Haiyan, Tripathi, Priyanka, Zhi, Wenbo, Spassieva, Stefka D., Morris, Andrew J., Bieberich, Erhard
• Format: Article
• Language: English
• Subjects: Animals; Cells, Cultured; Ceramide; Ceramides - metabolism; Docosahexaenoic Acids - metabolism; Fatty acids; Mice; Mice, Inbred C57BL; Mitochondria - metabolism; Models, Molecular; Peroxisomal Multifunctional Protein-2 - metabolism; Peroxisome-Targeting Signal 1 Receptor - metabolism; Peroxisomes; Peroxisomes - metabolism; Protein Interaction Maps; Protein Transport
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2019.05.017

The sphingolipid ceramide regulates beta-oxidation of medium and long chain fatty acids in mitochondria. It is not known whether it also regulates oxidation of very long chain fatty acids (VLCFAs) in peroxisomes. Using affinity chromatography, co-immunoprecipitation, and proximity ligation assays we discovered that ceramide interacts with Hsd17b4, an enzyme critical for peroxisomal VLCFA oxidation and docosahexaenoic acid (DHA) generation. Immunocytochemistry showed that Hsd17b4 is distributed to ceramide-enriched mitochondria-associated membranes (CEMAMs). Molecular docking and in vitro mutagenesis experiments showed that ceramide binds to the sterol carrier protein 2-like domain in Hsd17b4 adjacent to peroxisome targeting signal 1 (PTS1), the C-terminal signal for interaction with peroxisomal biogenesis factor 5 (Pex5), a peroxin mediating transport of Hsd17b4 into peroxisomes. Inhibition of ceramide biosynthesis induced translocation of Hsd17b4 from CEMAMs to peroxisomes, interaction of Hsd17b4 with Pex5, and upregulation of DHA. This data indicates a novel role of ceramide as a molecular switch regulating interaction of Hsd17b4 with Pex5 and peroxisomal function. •Hsd17b4 binds to ceramide at ceramide-enriched mitochondria-associated membranes (CEMAMs)•Association of Hsd17b4 with CEMAMS prevents its interaction with peroxisomal import protein Pex5 at peroxisomes.•Ceramide depletion induces translocation of Hsd17b4 to peroxisomes and upregulation of docosahexaenoic acid (DHA).•Our data indicates a novel role of ceramide as a molecular switch regulating peroxisomal function and generation of DHA.