title: Skn1 and Ipt1 negatively regulate autophagy in Saccharomyces cerevisiae.
abstract: We demonstrated that a yeast deletion mutant in IPT1 and SKN1, encoding proteins involved in the biosynthesis of mannosyldiinositolphosphoryl ceramides, is characterized by increased autophagy and DNA fragmentation upon nitrogen (N) starvation as compared with the single deletion mutants or wild type (WT). Apoptotic features were not significantly different between single and double deletion mutants upon N starvation, pointing to increased autophagy in the double Deltaipt1 Deltaskn1 deletion mutant independent of apoptosis. We observed increased basal levels of phytosphingosine in membranes of the double Deltaipt1 Deltaskn1 deletion mutant as compared with the single deletion mutants or WT. These data point to a negative regulation of autophagy by both Ipt1 and Skn1 in yeast, with a putative involvement of phytosphingosine in this process.
authors.affiliation: Centre of Microbial and Plant Genetics (CMPG), Katholieke Universiteit Leuven, Heverlee, Belgium. karin.thevissen@biw.kuleuven.be
authors.forename: Karin
authors.initials: K
authors.lastname: Thevissen
authors.forename: Wei-Lien
authors.initials: WL
authors.lastname: Yen
authors.forename: Didac
authors.initials: D
authors.lastname: Carmona-Gutierrez
authors.forename: Jolanta
authors.initials: J
authors.lastname: Idkowiak-Baldys
authors.forename: An M
authors.initials: AM
authors.lastname: Aerts
authors.forename: Isabelle E J A
authors.initials: IE
authors.lastname: François
authors.forename: Frank
authors.initials: F
authors.lastname: Madeo
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Klionsky
authors.forename: Yusuf A
authors.initials: YA
authors.lastname: Hannun
authors.forename: Bruno P A
authors.initials: BP
authors.lastname: Cammue
mesh_terms: D017209:Apoptosis; D001343:Autophagy; D002462:Cell Membrane / Q000737:chemistry; D053938:DNA Fragmentation; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: D008565:Membrane Proteins; C081932:SKN1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C109311:IPT1 protein, S cerevisiae; D017853:Phosphotransferases (Alcohol Group Acceptor); C012491:phytosphingosine; D009584:Nitrogen; D013110:Sphingosine