Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
FEMS Yeast Res. 2014 May;14(3):435-44. doi: 10.1111/1567-1364.12132. Epub 2014 Jan 23.
Pexophagy is a selective degradation pathway of peroxisomes. In the present study, we revealed that PpAtg21 was required for pexophagy in the methylotrophic yeast Pichia pastoris. PpAtg21 was essential for efficient lipidation of Atg8 and for de novo synthesis of pexophagic membranes. In contrast to PpAtg18, PpAtg21 was not necessary for vacuolar fission nor invagination during micropexophagy. PpAtg21 specifically bound to PI(3)P, but not to PI(3,5)P2 in vitro, and the localization analyses matched with this phosphoinositide-binding specificity. The mutant which lost the lipid-binding activity showed defect in pexophagy, suggesting that PI(3)P-binding activity of PpAtg21 was required for pexophagy.
pexophagy 是过氧化物酶体的一种选择性降解途径。在本研究中，我们揭示了 PpAtg21 在甲醇营养酵母巴斯德毕赤酵母的 pexophagy 中是必需的。PpAtg21 对于 Atg8 的有效脂质化和新合成的 pexophagic 膜是必需的。与 PpAtg18 不同，PpAtg21 对于微 pexophagy 期间的液泡分裂和内陷不是必需的。PpAtg21 特异性地结合 PI(3)P，但在体外不结合 PI(3,5)P2，并且定位分析与这种磷酸肌醇结合特异性相匹配。失去脂质结合活性的突变体在 pexophagy 中表现出缺陷，表明 PpAtg21 的 PI(3)P 结合活性是 pexophagy 所必需的。
