Engineering bacteriophytochrome-coupled photoactivated adenylyl cyclases for enhanced optogenetic cAMP modulation

Qianzhao Xu, Arend Vogt, Fabian Frechen, Chengwei Yi, Melike Küçükerden, Neville Ngum, Laia Sitjà Roqueta, Andreas Greiner, Rhein Parri, Mercè Masana, Nikolaus Wenger, Dagmar Wachten, Andreas Möglich

Research output: Contribution to journalArticlepeer-review


Sensory photoreceptors abound in nature and enable organisms to adapt behavior, development, and physiology to environmental light. In optogenetics, photoreceptors allow spatiotemporally precise, reversible, and non-invasive control by light of cellular processes. Notwithstanding the development of numerous optogenetic circuits, an unmet demand exists for efficient systems sensitive to red light, given its superior penetration of biological tissue. Bacteriophytochrome photoreceptors sense the ratio of red and far-red light to regulate the activity of enzymatic effector modules. The recombination of bacteriophytochrome photosensor modules with cyclase effectors underlies photoactivated adenylyl cyclases (PAC) that catalyze the synthesis of the ubiquitous second messenger 3', 5'-cyclic adenosine monophosphate (cAMP). Via homologous exchanges of the photosensor unit, we devised novel PACs, with the variant DmPAC exhibiting 40-fold activation of cyclase activity under red light, thus surpassing previous red-light-responsive PACs. Modifications of the PHY tongue modulated the responses to red and far-red light. Exchanges of the cyclase effector offer an avenue to further enhancing PACs but require optimization of the linker to the photosensor. DmPAC and a derivative for 3', 5'-cyclic guanosine monophosphate allow the manipulation of cyclic-nucleotide-dependent processes in mammalian cells by red light. Taken together, we advance the optogenetic control of second-messenger signaling and provide insight into the signaling and design of bacteriophytochrome receptors.

Original languageEnglish
Article number168257
Number of pages19
JournalJournal of molecular biology
Early online date31 Aug 2023
Publication statusE-pub ahead of print - 31 Aug 2023

Bibliographical note

This accepted manuscript version is licensed under the Creative Commons Attribution-NonCommercial License []. This license permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Acknowledgements: Financial support was provided by the European Commission (FET Open NEUROPA, grant 863214 to M.M., R.P., and A.M.), the Deutsche Forschungsgemeinschaft (grant MO2192/4-2 to A.M., SFB 1454 project 432325352 to D.W., TRR333/1 project 450149205 to D.W., EXC2151
project 390873048 to D.W.), the Else Kroener Fresenius Foundation (2021.EKFSE.53 to D.W.), the Young Investigator Project OptoImmun (DFG
SPP1926to A.V.), intramural funding from the University of Bonn (to D.W.), a Freigeist fellowship by the Volkswagen Stiftung (to N.W.), the Spanish Ministry of Sciences, Innovation and Universities (PID2021-124896OA-I00 and Marı ́a
de Maeztu Unit of Excellence, Institute of Neurosciences, University of Barcelona,
CEX2021-001159-M to M.M.).

This work is dedicated to Prof. Silvia E. Braslavsky, a pioneer in photobiology and photobiophysics, on her 80th birthday.


  • signal transduction
  • phytochrome
  • cyclic nucleotide
  • second messenger
  • sensory photoreceptor
  • synthetic biology
  • optogenetics


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