TY  - JOUR
A1  - Lu, Jinping
A1  - Dreyer, Ingo
A1  - Dickinson, Miles Sasha
A1  - Panzer, Sabine
A1  - Jaślan, Dawid
A1  - Navarro-Retamal, Carlos
A1  - Geiger, Dietmar
A1  - Terpitz, Ulrich
A1  - Becker, Dirk
A1  - Stroud, Robert M.
A1  - Marten, Irene
A1  - Hedrich, Rainer
T1  - Vicia faba SV channel VfTPC1 is a hyperexcitable variant of plant vacuole two pore channels
JF  - eLife
N2  - To fire action-potential-like electrical signals, the vacuole membrane requires the two-pore channel TPC1, formerly called SV channel. The TPC1/SV channel functions as a depolarization-stimulated, non-selective cation channel that is inhibited by luminal Ca\(^{2+}\). In our search for species-dependent functional TPC1 channel variants with different luminal Ca\(^{2+}\) sensitivity, we found in total three acidic residues present in Ca\(^{2+}\) sensor sites 2 and 3 of the Ca\(^{2+}\)-sensitive AtTPC1 channel from Arabidopsis thaliana that were neutral in its Vicia faba ortholog and also in those of many other Fabaceae. When expressed in the Arabidopsis AtTPC1-loss-of-function background, wild-type VfTPC1 was hypersensitive to vacuole depolarization and only weakly sensitive to blocking luminal Ca\(^{2+}\). When AtTPC1 was mutated for these VfTPC1-homologous polymorphic residues, two neutral substitutions in Ca\(^{2+}\) sensor site 3 alone were already sufficient for the Arabidopsis At-VfTPC1 channel mutant to gain VfTPC1-like voltage and luminal Ca\(^{2+}\) sensitivity that together rendered vacuoles hyperexcitable. Thus, natural TPC1 channel variants exist in plant families which may fine-tune vacuole excitability and adapt it to environmental settings of the particular ecological niche.
KW  - A. thaliana
KW  - Brassicaceae
KW  - Fabaceae
KW  - pore
KW  - potassium channel
KW  - voltage gating
KW  - vacuolar calcium sensor
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350264
VL  - 12
ER  - 
TY  - JOUR
A1  - Jaślan, Dawid
A1  - Dreyer, Ingo
A1  - Lu, Jinping
A1  - O'Malley, Ronan
A1  - Dindas, Julian
A1  - Marten, Irene
A1  - Hedrich, Rainer
T1  - Voltage-dependent gating of SV channel TPC1 confers vacuole excitability
JF  - Nature Communications
N2  - In contrast to the plasma membrane, the vacuole membrane has not yet been associated with electrical excitation of plants. Here, we show that mesophyll vacuoles from Arabidopsis sense and control the membrane potential essentially via the K\(^+\)-permeable TPC1 and TPK channels. Electrical stimuli elicit transient depolarization of the vacuole membrane that can last for seconds. Electrical excitability is suppressed by increased vacuolar Ca\(^{2+}\) levels. In comparison to wild type, vacuoles from the fou2 mutant, harboring TPC1 channels insensitive to luminal Ca\(^{2+}\), can be excited fully by even weak electrical stimuli. The TPC1-loss-of-function mutant tpc1-2 does not respond to electrical stimulation at all, and the loss of TPK1/TPK3-mediated K\(^{+}\) transport affects the duration of TPC1-dependent membrane depolarization. In combination with mathematical modeling, these results show that the vacuolar K\(^+\)-conducting TPC1 and TPK1/TPK3 channels act in concert to provide for Ca\(^{2+}\)- and voltage-induced electrical excitability to the central organelle of plant cells.
KW  - Biophysics
KW  - Plant signalling
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202029
VL  - 10
ER  -