The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous ...The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous studies revealed that these calcium- and voltage-activated, nonselective cation channels are expressed in the vacuoles of all plants and every plant tissue. The voltage-dependent properties of the SV channel are susceptible to modulation by calcium, pH, redox state, as well as regulatory proteins. In Arabidopsis, the SV channel is encoded by the AtTPC1 gene, and even though its gene product represents the by far largest conductance of the vacuolar membrane, tpcl-loss-of-function mutants appeared not to be impaired in major physiological functions such as growth, development, and reproduction. In contrast, the fou2 gain-of-function point mutation D454N within TPC1 leads to a pronounced growth phenotype and increased synthesis of the stress hormone jasmonate. Since the TPC1 gene is present in all land plants, it likely encodes a very general function. In this review, we will discuss major SV channel properties and their impact on plant cell physiology.展开更多
Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its...Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.展开更多
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-...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.展开更多
文摘The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous studies revealed that these calcium- and voltage-activated, nonselective cation channels are expressed in the vacuoles of all plants and every plant tissue. The voltage-dependent properties of the SV channel are susceptible to modulation by calcium, pH, redox state, as well as regulatory proteins. In Arabidopsis, the SV channel is encoded by the AtTPC1 gene, and even though its gene product represents the by far largest conductance of the vacuolar membrane, tpcl-loss-of-function mutants appeared not to be impaired in major physiological functions such as growth, development, and reproduction. In contrast, the fou2 gain-of-function point mutation D454N within TPC1 leads to a pronounced growth phenotype and increased synthesis of the stress hormone jasmonate. Since the TPC1 gene is present in all land plants, it likely encodes a very general function. In this review, we will discuss major SV channel properties and their impact on plant cell physiology.
文摘Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.
文摘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.
