TOR kinase activity in Chlamydomonas reinhardtii is modulated by cellular metabolic states

AbstractTarget Of Rapamycin (TOR) kinase is a sensor as well as a central integrator of internal and external metabolic cues. However, in algae and in higher plants, the components of TOR kinase ‐signaling are yet to be characterized. Here, we establish an assay system to study TOR kinase activity inChlamydomonas reinhardtii using the phosphorylation status of its putative downstream target, CrS6K. Using this assay, we probe the modulation of cellular TOR kinase activity under various physiological states such as photoautotrophy, heterotrophy, mixotrophy and nitrogen (N) ‐starvation. Importantly, we uncover that excess acetate in the medium leads to high cellular ROS levels, triggering autophagy and a concomitant drop in TOR kinase activity in a dose‐dependent manner, thus leading to a N‐starvation‐like cellular phenotype, even when nitrogen is present.

Source: FEBS Letters - July 16, 2020 Category: Biochemistry Authors: Shivani Upadhyaya, Shreya Agrawal, Anmol Gorakshakar, Basuthkar Jagadeeshwar Rao Tags: RESEARCH ARTICLES Source Type: research