Akihiro C. E. Shibata1, Hiromi H. Ueda1,2, Kei Eto2,3, Maki Onda1, Aiko Sato1, Tatsuko Ohba3, Junichi Nabekura2,3 & Hideji Murakoshi1,2
1 Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki (Japan); 2 Department of Physiological Sciences, The Graduate University for Advanced Studies, Hayama (Japan); 3 Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki (Japan).
Optogenetic approaches for studying neuronal functions have proven their utility in the neurosciences. However, optogenetic tools capable of inducing synaptic plasticity at the level of single synapses have been lacking. Here, we engineered a photoactivatable (pa)CaMKII by fusing a light-sensitive domain, LOV2, to CaMKIIα. Blue light or two-photon excitation reversibly activated paCaMKII. Activation in single spines was sufficient to induce structural long-term potentiation (sLTP) in vitro and in vivo. paCaMKII activation was also sufficient for the recruitment of AMPA receptors and functional LTP in single spines. By combining paCaMKII with protein activity imaging by 2-photon FLIM-FRET, we demonstrate that paCaMKII activation in clustered spines induces robust sLTP via a mechanism that involves the actin-regulatory small GTPase, Cdc42. This optogenetic tool for dissecting the function of CaMKII activation (i.e., the sufficiency of CaMKII rather than necessity) and for manipulating synaptic plasticity will find many applications in neuroscience and other fields.
To activate paCaMKII, the samples were continuously illuminated by a blue LED (470 nm LED; CoolLED) with a bandpass filter (FF01-469/35-25; Chroma) at 35 mW cm−2 for 2 s.
Product Associated Features
The pE-100 series is a family of single-wavelength fluorescence LED Illumination Systems, and in this case the pE-100 (470 nm) provides specific and controllable photoactivation.
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