Functional analyses of differentially expressed isoforms of the Arabidopsis inositol phosphorylceramide synthase

• Published in: Plant molecular biology Vol. 73; no. 4-5; pp. 399 - 407
• Main Authors: Mina, J. G, Okada, Y, Wansadhipathi-Kannangara, N. K, Pratt, S, Shams-Eldin, H, Schwarz, R. T, Steel, P. G, Fawcett, T, Denny, P. W
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.07.2010; Springer Netherlands; Springer Nature B.V
• Subjects: Arabidopsis; Arabidopsis - drug effects; Arabidopsis - enzymology; Arabidopsis - genetics; AUR1; Biochemistry; Biomedical and Life Sciences; Chemical synthesis; Depsipeptides - pharmacology; Drug Resistance - drug effects; Enzymatic activity; Eukaryotes; Expressed Sequence Tags; Expression; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Enzymologic - drug effects; Gene Expression Regulation, Plant - drug effects; Genetic Complementation Test; Hexosyltransferases - genetics; Hexosyltransferases - metabolism; Inositol phosphorylceramide; IPC synthase; Isoenzymes - genetics; Isoenzymes - metabolism; Life Sciences; Membranes; Mutation - genetics; Oligonucleotide Array Sequence Analysis; Plant biology; Plant Pathology; Plant Sciences; Plasma; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - metabolism; sphingolipids; Sphingolipids; IPC synthase; Arabidopsis; Expression; AUR1; Inositol phosphorylceramide
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-010-9626-3

Sphingolipids are key components of eukaryotic plasma membranes that are involved in many functions, including the formation signal transduction complexes. In addition, these lipid species and their catabolites function as secondary signalling molecules in, amongst other processes, apoptosis. The biosynthetic pathway for the formation of sphingolipid is largely conserved. However, unlike mammalian cells, fungi, protozoa and plants synthesize inositol phosphorylceramide (IPC) as their primary phosphosphingolipid. This key step involves the transfer of the phosphorylinositol group from phosphatidylinositol (PI) to phytoceramide, a process catalysed by IPC synthase in plants and fungi. This enzyme activity is at least partly encoded by the AUR1 gene in the fungi, and recently the distantly related functional orthologue of this gene has been identified in the model plant Arabidopsis. Here we functionally analysed all three predicted Arabidopsis IPC synthases, confirming them as aureobasidin A resistant AUR1p orthologues. Expression profiling revealed that the genes encoding these orthologues are differentially expressed in various tissue types isolated from Arabidopsis.