Michaeli Simon, Honig Arik, Levanony Hanna, Peled-Zehavi Hadas, Galili Gad
Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel.
Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
Plant Cell. 2014 Oct;26(10):4084-101. doi: 10.1105/tpc.114.129999. Epub 2014 Oct 3.
Selective autophagy has been extensively studied in various organisms, but knowledge regarding its functions in plants, particularly in organelle turnover, is limited. We have recently discovered ATG8-INTERACTING PROTEIN1 (ATI1) from Arabidopsis thaliana and showed that following carbon starvation it is localized on endoplasmic reticulum (ER)-associated bodies that are subsequently transported to the vacuole. Here, we show that following carbon starvation ATI1 is also located on bodies associating with plastids, which are distinct from the ER ATI bodies and are detected mainly in senescing cells that exhibit plastid degradation. Additionally, these plastid-localized bodies contain a stroma protein marker as cargo and were observed budding and detaching from plastids. ATI1 interacts with plastid-localized proteins and was further shown to be required for the turnover of one of them, as a representative. ATI1 on the plastid bodies also interacts with ATG8f, which apparently leads to the targeting of the plastid bodies to the vacuole by a process that requires functional autophagy. Finally, we show that ATI1 is involved in Arabidopsis salt stress tolerance. Taken together, our results implicate ATI1 in autophagic plastid-to-vacuole trafficking through its ability to interact with both plastid proteins and ATG8 of the core autophagy machinery.
选择性自噬已在多种生物体中得到广泛研究，但关于其在植物中的功能，尤其是在细胞器周转方面的了解仍然有限。我们最近从拟南芥中发现了与ATG8相互作用的蛋白1（ATI1），并表明在碳饥饿后，它定位于内质网（ER）相关体上，这些体随后被转运至液泡。在此，我们表明在碳饥饿后，ATI1也位于与质体相关的体上，这些体与ER ATI体不同，主要在表现出质体降解的衰老细胞中被检测到。此外，这些质体定位的体含有一种基质蛋白标记物作为货物，并观察到它们从质体上出芽和脱离。ATI1与质体定位的蛋白定位的蛋白相互作用，并进一步表明它是其中一种蛋白周转所必需的，作为一个代表。质体体上的ATI1也与ATG8f相互作用，这显然导致质体体通过一个需要功能性自噬的过程被靶向至液泡。最后，我们表明ATI1参与拟南芥的盐胁迫耐受性。综上所述，我们的结果表明ATI1通过其与质体蛋白和核心自噬机制的ATG8相互作用的能力，参与自噬性的质体到液泡的运输。
