TY  - JOUR
A1  - Lehmann, Julian
A1  - Jørgensen, Morten E.
A1  - Fratz, Stefanie
A1  - Müller, Heike M.
A1  - Kusch, Jana
A1  - Scherzer, Sönke
A1  - Navarro-Retamal, Carlos
A1  - Mayer, Dominik
A1  - Böhm, Jennifer
A1  - Konrad, Kai R.
A1  - Terpitz, Ulrich
A1  - Dreyer, Ingo
A1  - Mueller, Thomas D.
A1  - Sauer, Markus
A1  - Hedrich, Rainer
A1  - Geiger, Dietmar
A1  - Maierhofer, Tobias
T1  - Acidosis-induced activation of anion channel SLAH3 in the flooding-related stress response of Arabidopsis
JF  - Current Biology
N2  - Plants, as sessile organisms, gained the ability to sense and respond to biotic and abiotic stressors to survive severe changes in their environments. The change in our climate comes with extreme dry periods but also episodes of flooding. The latter stress condition causes anaerobiosis-triggered cytosolic acidosis and impairs plant function. The molecular mechanism that enables plant cells to sense acidity and convey this signal via membrane depolarization was previously unknown. Here, we show that acidosis-induced anion efflux from Arabidopsis (Arabidopsis thaliana) roots is dependent on the S-type anion channel AtSLAH3. Heterologous expression of SLAH3 in Xenopus oocytes revealed that the anion channel is directly activated by a small, physiological drop in cytosolic pH. Acidosis-triggered activation of SLAH3 is mediated by protonation of histidine 330 and 454. Super-resolution microscopy analysis showed that the increase in cellular proton concentration switches SLAH3 from an electrically silent channel dimer into its active monomeric form. Our results show that, upon acidification, protons directly switch SLAH3 to its open configuration, bypassing kinase-dependent activation. Moreover, under flooding conditions, the stress response of Arabidopsis wild-type (WT) plants was significantly higher compared to SLAH3 loss-of-function mutants. Our genetic evidence of SLAH3 pH sensor function may guide the development of crop varieties with improved stress tolerance.
KW  - SLAH3
KW  - S-type anion channel
KW  - hypoxia
KW  - pH
KW  - cytosolic acidification
KW  - flooding
KW  - PALM
KW  - stoichiometry
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-363320
VL  - 31
ER  - 
TY  - JOUR
A1  - Endesfelder, Ulrike
A1  - Malkusch, Sebastian
A1  - Flottmann, Benjamin
A1  - Mondry, Justine
A1  - Liguzinski, Piotr
A1  - Verveer, Peter J.
A1  - Heilemann, Mike
T1  - Chemically Induced Photoswitching of Fluorescent Probes - A General Concept for Super-Resolution Microscopy
N2  - We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.
KW  - Super-Resolution Microscopy
KW  - photoswitchable organic fluorophores
KW  - fluorescent proteins
KW  - super-resolution
KW  - PALM
KW  - dSTORM
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-74896
ER  - 
TY  - JOUR
A1  - Endesfelder, Ulrike
A1  - Malkusch, Sebastian
A1  - Flottmann, Benjamin
A1  - Mondry, Justine
A1  - Liguzinski, Piotr
A1  - Verveer, Peter J.
A1  - Heilemann, Mike
T1  - Chemically Induced Photoswitching of Fluorescent Probes - A General Concept for Super-Resolution Microscopy
JF  - Molecules
N2  - We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.
KW  - Photoactivated localization microscopy
KW  - Fusion proteins
KW  - Molecules
KW  - Patterns
KW  - Switch
KW  - Limit
KW  - Time
KW  - photoswitchable organic fluorophores
KW  - fluorescent proteins
KW  - super-resolution
KW  - PALM
KW  - dSTORM
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134080
VL  - 16
IS  - 4
ER  -