Quantitatively Assessing Co-Localization of Golgi Proteins by Distance Analysis Using the DiAna Software

This method determines if two fluorescently labeled proteins are in close proximity to each other in situ. It is an alternative to commonly used co-localization assays and is based on measuring distances between pairs of objects representative of the two proteins. It makes use of a relatively recently developed ImageJ plugin called DiAna, which employs semi-automated object recognition and subsequent distance analysis of the recognized objects. The advantages of this method are that it is largely independent of the actual pixel intensity values, quite robust against background noise, and not reliant on arbitrarily set intensity threshold values. We present here a use case for the DiAna plugin in the context of plant cells with fluorescently labeled subcellular structures, such as proteins associated with the plant Golgi apparatus.