@article{PanzerZhangKonteetal.2021,
  author    = {Panzer, Sabine and Zhang, Chong and Konte, Tilen and Br{\"a}uer, Celine and Diemar, Anne and Yogendran, Parathy and Yu-Strzelczyk, Jing and Nagel, Georg and Gao, Shiqiang and Terpitz, Ulrich},
  title     = {Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates},
  series = {Frontiers in Molecular Biosciences},
  volume    = {8},
  journal   = {Frontiers in Molecular Biosciences},
  issn      = {2296-889X},
  doi       = {10.3389/fmolb.2021.750528},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249248},
  year      = {2021},
  abstract  = {Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications.},
  language  = {en}
}
@article{PanzerBrychBatschaueretal.2019,
  author    = {Panzer, Sabine and Brych, Annika and Batschauer, Alfred and Terpitz, Ulrich},
  title     = {Opsin 1 and Opsin 2 of the corn smut fungus ustilago maydis are green light-driven proton pumps},
  series = {Frontiers in Microbiology},
  volume    = {10},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2019.00735},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201453},
  pages     = {735},
  year      = {2019},
  abstract  = {In fungi, green light is absorbed by rhodopsins, opsin proteins carrying a retinal molecule as chromophore. The basidiomycete Ustilago maydis, a fungal pathogen that infects corn plants, encodes three putative photoactive opsins, called ops1 (UMAG_02629), ops2 (UMAG_00371), and ops3 (UMAG_04125). UmOps1 and UmOps2 are expressed during the whole life cycle, in axenic cultures as well as in planta, whereas UmOps3 was recently shown to be absent in axenic cultures but highly expressed during plant infection. Here we show that expression of UmOps1 and UmOps2 is induced by blue light under control of white collar 1 (Wco1). UmOps1 is mainly localized in the plasma membrane, both when expressed in HEK cells and U. maydis sporidia. In contrast, UmOps2 was mostly found intracellularly in the membranes of vacuoles. Patch-clamp studies demonstrated that both rhodopsins are green light-driven outward rectifying proton pumps. UmOps1 revealed an extraordinary pH dependency with increased activity in more acidic environment. Also, UmOps1 showed a pronounced, concentration-dependent enhancement of pump current caused by weak organic acids (WOAs), especially by acetic acid and indole-3-acetic acid (IAA). In contrast, UmOps2 showed the typical behavior of light-driven, outwardly directed proton pumps, whereas UmOps3 did not exhibit any electrogenity. With this work, insights were gained into the localization and molecular function of two U. maydis rhodopsins, paving the way for further studies on the biological role of these rhodopsins in the life cycle of U. maydis.},
  language  = {en}
}
@article{GarciaMartinezBrunkAvalosetal.2015,
  author    = {Garc{\´i}a-Mart{\´i}nez, Jorge and Brunk, Michael and Avalos, Javier and Terpitz, Ulrich},
  title     = {The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination},
  series = {Scientific Reports},
  volume    = {5},
  journal   = {Scientific Reports},
  number    = {7798},
  doi       = {10.1038/srep07798},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149049},
  year      = {2015},
  abstract  = {Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO\(^{-}\) mutant and carO\(^{+}\) control strains showed a faster development of light-exposed carO-germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin.},
  language  = {en}
}