alpha/beta Hydrolase Domain-containing 6 (ABHD6) Degrades the Late Endosomal/Lysosomal Lipid Bis(monoacylglycero)phosphate

作者：Pribasnig Maria A; Mrak Irina; Grabner Gernot F; Taschler Ulrike; Knittelfelder Oskar; Scherz Barbara; Eichmann Thomas O; Heier Christoph; Grumet Lukas; Kowaliuk Jakob; Romauch Matthias; Holler Stefan; Anderl Felix; Wolinski Heimo; Lass Achim; Breinbauer Rolf; Marsche Gunther; Brown J Mark; Zimmermann Robert^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2015, 290(50): 29869-29881.

DOI：10.1074/jbc.M115.669168

alpha/beta Hydrolase domain-containing 6 (ABHD6) can act as monoacylglycerol hydrolase and is believed to play a role in endocannabinoid signaling as well as in the pathogenesis of obesity and liver steatosis. However, the mechanistic link between gene function and disease is incompletely understood. Here we aimed to further characterize the role of ABHD6 in lipid metabolism. We show that mouse and human ABHD6 degrade bis(monoacylglycero)phosphate (BMP) with high specific activity. BMP, also known as lysobisphosphatidic acid, is enriched in late endosomes/lysosomes, where it plays a key role in the formation of intraluminal vesicles and in lipid sorting. Up to now, little has been known about the catabolism of this lipid. Our data demonstrate that ABHD6 is responsible for similar to 90% of the BMP hydrolase activity detected in the liver and that knockdown of ABHD6 increases hepatic BMP levels. Tissue fractionation and live-cell imaging experiments revealed that ABHD6 co-localizes with late endosomes/lysosomes. The enzyme is active at cytosolic pH and lacks acid hydrolase activity, implying that it degrades BMP exported from acidic organelles or de novo-formed BMP. In conclusion, our data suggest that ABHD6 controls BMP catabolism and is therefore part of the late endosomal/lysosomal lipid-sorting machinery.

• 出版日期2015-12-11