Two-photon excitation facilitates fluorescence fluctuation spectroscopy experiments by providing a well-defined observation volume that is identical across multiple emitting species. We have developed a multi-color approach, spatial cumulant analysis (SpCA), which provides images of molecular stoichiometries. We have used SpCA to determine the dynamics of dopamine receptors (DR) on the insulin secreting β-cells. There are two inhibitory DRs in the β-cell, D2 and D3, which differentially impact cAMP production, Ca2+ influx, and K+ currents. We show how multicolor spatial cumulant analysis of labeled proteins of interest can accurately measure the stoichiometry of receptors, G-proteins, and downstream signaling targets.

Date Published: 9 March 2020
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Proc. SPIE 11244, Multiphoton Microscopy in the Biomedical Sciences XX, 1124406 (9 March 2020); doi: 10.1117/12.2543117

Published in SPIE Proceedings Vol. 11244:
Multiphoton Microscopy in the Biomedical Sciences XX
Ammasi Periasamy; Peter T. C. So; Karsten König, Editor(s)