A SPIM-FCCS <i>in vivo</i> control measurement of the eGFP-mRFP1 fusion protein (upper row) and eGFP and mRFP1 monomers (lower row) expressed in HeLa cells.

<p>(A), (B) and (C) the intensity image, slow and fast diffusion coefficient and relative concentration maps, respectively. (D) and (E) correlation functions and fits for the fusion protein and the monomers, horizontal dashed lines indicate the cross-correlation explained by cross-talk.