Anti-Arc nanobodies as tools for structural and functional biology
Nanobodies are single-domain fragments obtained from camelid antibodies, which have high affinity towards their target protein. Two recent publications describe the development and use of nanobodies directed against the neuronal Arc protein to promote both structure determination, imaging and detection, and functional studies.
Arc is a neuronal protein considered to be central in long-term memory formation. In addition, it can form virus-like capsids that may transduce molecular signals between neighbouring cells. The structure of full-length Arc has remained unknown.
Together with the group of Clive Bramham, we have developed a set of anti-Arc nanobodies, which bind to Arc with nanomolar affinity. These nanobodies form stable complexes with Arc, and we have used them to obtain crystal and solution structures of Arc. In addition, the nanobodies have been tested in different detection and imaging methods, and they can be expressed in living cells, with hopes of being able to modulate Arc function. Structural and biophysical experiments revealed that at least one of the nanobodies directly competes with the Arc ligand stargazin.
The nanobodies are described in two recent publications:
Ishizuka Y., Mergiya T.F., Baldinotti R., Xu J., Hallin E.I., Markússon S., Kursula P. & Bramham C.R. (2022) Development and validation of Arc nanobodies: new tools for probing Arc dynamics and function. Neurochem. Res., in press. Link
Markússon S., Hallin E.I., Bustad H.J., Raasakka A., Xu J., Muruganandam G., Loris R., Martinez A., Bramham C.R. & Kursula P. (2022) High-affinity anti-Arc nanobodies provide tools for structural and functional studies. PLoS ONE, in press. Link