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Characterization of a rhodopsin-phosphodiesterase from Choanoeca flexa to be combined with rhodopsin-cyclases for bidirectional optogenetic cGMP control

Year: 2025
Type: article
Abstract: Rhodopsin phosphodiesterases (RhPDEs) were first discovered in the choanoflagellate Salpingoeca rosetta , but their physiological role remained unknown. Their light-dependent modulation was found to be low, limiting optogenetic application. However, recent in vivo studies in the choanoflagellate Choanoeca flexa revealed a strong linkage of RhPDE to the actomyosin-mediated contraction and colony sheet inversion and identified downstream cGMP effectors. Through screening various RhPDE variants from C. flexa , we identified four photomodulated PDEs of which C . flexa RhPDE1 (CfRhPDE1) revealed the highest cGMP affinity and the most pronounced light regulation with K m values of 1.9 and 4.4 μM in light and darkness. By coexpressing CfRhPDE1 with the rhodopsin-guanylyl-cyclase from the fungus Catenaria anguillulae and a cyclic nucleotide-gated ion channel from olfactory neurons in ND7/23 cells, we demonstrate bidirectional dual-color modulation of cGMP levels and ion channel conductance. Together with spectroscopic characterization, our fast functional recordings suggest that the M-state of the photocycle initiates functional changes in the phosphodiesterase domain via rapid rhodopsin-PDE coupling. With efficient expression and 3.5 s lifetime of the active state, this protein provides high photosensitivity to the host cells. This demonstrates that RhPDEs can regulate cGMP signaling in mammalian cells on a subsecond timescale, closing a present gap in optogenetics and assisting researchers in setting up multicomponent optogenetic systems for bidirectional control of cyclic nucleotides.
DOI: 10.1016/j.jbc.2025.108401
Language: English
Open Access status: gold
Estimated APC paid: $3,430
OpenAlex ID: W4408319082
FWCI: 0.712
Cites: 39
Cited by: 2
Related to: 10