title: Zebrafish fat-free, a novel Arf effector, regulates phospholipase D to mediate lipid and glucose metabolism.
abstract: Zebrafish fat-free mutants (ffr) exhibit defective intestinal lipid metabolism and fat-free protein (Ffr) is involved in Golgi-related vesicular trafficking. In this study, we show that ffr mutants also display defective glucose metabolism. Using microarray and real-time PCR, we found that a ffr mutant with a nonsense mutation exhibits increased transcript level of ADP-ribosylation factor gene (arfs). Further analysis indicated that Ffr contains a putative Arf binding motif and can bind GTP-bound Arfs. In addition, ffr exhibited increased transcript and activity levels of the Arf downstream effector phospholipase D (PLD). Inhibition of PLD partially restored lipid and glucose metabolism in ffr, suggesting that Ffr is involved in a pathway regulating PLD activity by regulating Arfs. We propose that local over-production of phosphatidic acid (PA) by excess PLD promotes membrane curvature, which affects Golgi membrane structure and secretory processes, contributing to impairment of lipid and glucose metabolism.
authors.affiliation: Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Hsing-Yin
authors.initials: HY
authors.lastname: Liu
authors.forename: Nancy
authors.initials: N
authors.lastname: Lee
authors.forename: Tsen-Yi
authors.initials: TY
authors.lastname: Tsai
authors.forename: Shiu-Ying
authors.initials: SY
authors.lastname: Ho
mesh_terms: D020001:1-Butanol / Q000494:pharmacology; D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D050356:Lipid Metabolism; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D015027:Zebrafish
chemical_list: D017931:DNA Primers; D004791:Enzyme Inhibitors; D020001:1-Butanol; D010739:Phospholipase D; D020727:ADP-Ribosylation Factors; D005947:Glucose