摘要：SummaryConserved translocator proteins (TSPOs) mediate cell stress responses possibly in a cell-type-specific manner. This work reports on the molecular function of plant TSPO and their possible evolutionary divergence.Arabidopsis thalianaTSPO (AtTSPO) is stress induced and has a conserved polybasic, plant-specific N-terminal extension. AtTSPO reduces water loss by depleting aquaporin PIP2;7 in the plasma membrane. Herein, AtTSPO was found to bind phosphoinositidesin vitro, but only full-length AtTSPO or chimeric mouse TSPO with an AtTSPO N-terminus bound PI(4,5)P2in vitroand modified PIP2;7 levelsin vivo. Expression of AtTSPO but not its N-terminally truncated variant enhanced phospholipase C activity and depleted PI(4,5)P2from the plasma membrane and its enrichment in Golgi membranes. Deletion or point mutations within the AtTSPO N-terminus affected PI(4,5)P2binding and almost prevented AtTSPO-PIP2;7 interactionin vivo. The findings imply functional divergence of plant TSPOs from bacterial and animal counterparts via evolutionary acquisition of the phospholipid-interacting N-terminus.Graphical AbstractDisplay OmittedHighlights•Plant TSPOs possess a specific and structurally conserved polybasic N-terminal extension•Plant TSPOs bind PI(4,5)P2in vitroand at the Golgi membranein vivo•The polybasic N-terminal extension is required for PI(4,5)P2binding•Plant TSPO depletes the plasma membrane of both an aquaporin and a PI(4,5)P2Cell Biology; Plant Biology; Plant Physiology
