Major vacuolar TPC1 channel in stress signaling:what matters,K^(+),Ca^(2+) conductance or an ion‑flux independent mechanism?  

作　　者：Igor Pottosin Oxana Dobrovinskaya 

机构地区：[1]Biomedical Center,University of Colima,28045 Colima,Mexico [2]International Research Centre for Environmental Membrane Biology,Foshan University,Foshan 528041,China

出　　处：《Stress Biology》2022年第1期312-323,共12页逆境生物学（英文）

摘　　要：Two-pore cation channel,TPC1,is ubiquitous in the vacuolar membrane of terrestrial plants and mediates the long distance signaling upon biotic and abiotic stresses.It possesses a wide pore,which transports small mono-and divalent cations.K^(+) is transported more than 10-fold faster than Ca^(2+) ,which binds with a higher affinity within the pore.Key pore residues,responsible for Ca^(2+) binding,have been recently identified.There is also a substantial pro-gress in the mechanistic and structural understanding of the plant TPC1 gating by membrane voltage and cytosolic and luminal Ca^(2+).Collectively,these gating factors at resting conditions strongly reduce the potentially lethal Ca^(2+) leak from the vacuole.Such tight control is impressive,bearing in mind high unitary conductance of the TPC1 and its abundance,with thousands of active channel copies per vacuole.But it remains a mystery how this high thresh-old is overcome upon signaling,and what type of signal is emitted by TPC1,whether it is Ca^(2+)or electrical one,or a transduction via protein conformational change,independent on ion conductance.Here we discuss non-exclusive scenarios for the TPC1 integration into Ca^(2+),ROS and electrical signaling.

关 键 词：TPC1 POTASSIUM Calcium Voltage gating Long-distance signaling VACUOLE 

分 类 号：Q89[生物学]