Optically triggering spatiotemporally confined GPCR activity in a cell and programming neurite initiation and extension.

W K Ajith Karunarathne, Lopamudra Giri, Vani Kalyanaraman, N Gautam

Proceedings of the National Academy of Sciences of the United States of America 2013 Apr 23

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G-protein-coupled receptor (GPCR) activity gradients evoke important cell behavior but there is a dearth of methods to induce such asymmetric signaling in a cell. Here we achieved reversible, rapidly switchable patterns of spatiotemporally restricted GPCR activity in a single cell. We recruited properties of nonrhodopsin opsins--rapid deactivation, distinct spectral tuning, and resistance to bleaching--to activate native Gi, Gq, or Gs signaling in selected regions of a cell. Optical inputs were designed to spatiotemporally control levels of second messengers, IP3, phosphatidylinositol (3,4,5)-triphosphate, and cAMP in a cell. Spectrally selective imaging was accomplished to simultaneously monitor optically evoked molecular and cellular response dynamics. We show that localized optical activation of an opsin-based trigger can induce neurite initiation, phosphatidylinositol (3,4,5)-triphosphate increase, and actin remodeling. Serial optical inputs to neurite tips can refashion early neuron differentiation. Methods here can be widely applied to program GPCR-mediated cell behaviors.

Citation

W K Ajith Karunarathne, Lopamudra Giri, Vani Kalyanaraman, N Gautam. Optically triggering spatiotemporally confined GPCR activity in a cell and programming neurite initiation and extension. Proceedings of the National Academy of Sciences of the United States of America. 2013 Apr 23;110(17):E1565-74