Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario (CEFOBI-CONICET/UNR), Rosario, Argentina.
Umeå Plant Science Centre, Department of Plant Physiologyogy, Umeå University, Sweden.
J Exp Bot. 2019 Apr 15;70(8):2325-2338. doi: 10.1093/jxb/erz023.
Sucrose non-fermenting 1 (SNF1)-related protein kinase 1.1 (SnRK1.1; also known as KIN10 or SnRK1α) has been identified as the catalytic subunit of the complex SnRK1, the Arabidopsis thaliana homologue of a central integrator of energy and stress signalling in eukaryotes dubbed AMPK/Snf1/SnRK1. A nuclear localization of SnRK1.1 has been previously described and is in line with its function as an integrator of energy and stress signals. Here, using two biological models (Nicotiana benthamiana and Arabidopsis thaliana), native regulatory sequences, different microscopy techniques, and manipulations of cellular energy status, it was found that SnRK1.1 is localized dynamically between the nucleus and endoplasmic reticulum (ER). This distribution was confirmed at a spatial and temporal level by co-localization studies with two different fluorescent ER markers, one of them being the SnRK1.1 phosphorylation target HMGR. The ER and nuclear localization displayed a dynamic behaviour in response to perturbations of the plastidic electron transport chain. These results suggest that an ER-associated SnRK1.1 fraction might be sensing the cellular energy status, being a point of crosstalk with other ER stress regulatory pathways.
SNF1 相关蛋白激酶 1.1（SnRK1.1；也称为 KIN10 或 SnRK1α）已被鉴定为复合物 SnRK1 的催化亚基，该复合物是真核生物中能量和应激信号中央整合因子 AMPK/Snf1/SnRK1 的拟南芥同源物。先前已经描述了 SnRK1.1 的核定位，这与其作为能量和应激信号整合因子的功能一致。在这里，使用两种生物模型（烟草和拟南芥）、天然调节序列、不同的显微镜技术以及细胞能量状态的操作，发现 SnRK1.1 在核和内质网（ER）之间动态定位。通过与两种不同荧光 ER 标记物的共定位研究，在时空水平上证实了这种分布，其中一种标记物是 SnRK1.1 的磷酸化靶标 HMGR。内质网和核定位对质体电子传递链的扰动表现出动态行为。这些结果表明，与内质网相关的 SnRK1.1 部分可能正在感知细胞能量状态，是与其他内质网应激调节途径交叉对话的一个点。
