How to quantify if one signal is on the "surface" of another in 3D?

Hi All, I have two fluorescent proteins that associate with each other. Protein A appears to form a shell like structure around protein B. I am trying to find a way to quantify this in 3D. My first idea was to make a 3D mask that accounts for all signal A+B, then make equal sized “shells” within that mask to quantify how much of each protein is in the shells. The idea being that if protein A is on the outer edges than more signal will be in the outer shells compared to protein B which will have mostly signal in the inner shells.

However, I cant seem to find a plugin for imageJ that would allow me to do this. If anyone knows how, or has another suggestion to quantify this I would really appreciate it!

1 Like