Functions of PI4P and sterol glucoside are necessary for the synthesis of a nascent membrane structure during pexophagy.
We recently showed that, in the yeast Pichia pastoris, an ergosterol glucoside synthesizing enzyme, Atg26, is recruited to the precursor of the pexophagic structure, micropexophagic membrane apparatus (MIPA), under the regulation of phosphatidylinositol 4'-monophosphate (PI4P)-signaling during pexophagy. Atg26 was found to harbor a novel PI4P-binding motif, the GRAM domain. Both lipids, PI4P and sterol glucoside, synthesized by PpPik1 and PpAtg26, respectively, were necessary for pexophagy, in the step where the MIPA was formed. In this addendum, we review these findings, and speculate on the mechanistic and physiological implications of the functions of these lipids during the autophagic process.
Yamashita
Shun-ichi
S
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
Oku
Masahide
M
Sakai
Yasuyoshi
Y
D000818:Animals; D001343:Autophagy / Q000502:physiology*; D021961:Cell Membrane Structures / Q000378:metabolism*; D005964:Glucosyltransferases / Q000502:physiology*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008322:Mammals / Q000502:physiology; D008954:Models, Biological; D018129:Phosphatidylinositol Phosphates / Q000502:physiology*; D010843:Pichia / Q000502:physiology; D012641:Selection, Genetic; D013261:Sterols / Q000378:metabolism; D015003:Yeasts / Q000502:physiology
D018129:Phosphatidylinositol Phosphates; D013261:Sterols; C037178:phosphatidylinositol 4-phosphate; D005964:Glucosyltransferases