Skip to main content
. Author manuscript; available in PMC: 2020 Mar 15.
Published in final edited form as: Methods. 2018 Sep 28;157:28–41. doi: 10.1016/j.ymeth.2018.09.008

Fig. 2. Illustration of FFS in the cytoplasm.

Fig. 2.

A) The PSF (red oval) is completely embedded within the cytoplasm. B) The entire volume of the PSF is accessible to the fluorescent proteins. Therefore the OV is equivalent to the PSF volume. C) The fluorescence signal fluctuates in time reflecting the passage of proteins through the OV. D) The brightness titration curve of a FP-labeled monomer is independent of concentration (dashed line). A labeled protein that forms dimers leads to a concentration-dependent brightness titration curve (solid line) that increases from 1 to 2. The x-axis depicts either molar concentration c or the occupation number N.