This is just a simple definition/jargon question but why are fluorescent probes called two different names? For example why is GFP called GFP and Alexa Fluor 488?
GFP stands for green fluorescent protein and is the aequorin interaction partner used for bioluminescence by some species of jellyfish. GFP can be expressed as a fusion protein tagged onto a protein of interest to allow visualization when excited by a light source of the correct frequency. Alexa Fluor 488 is a phalloidin toxin that has been labelled with a synthetic dye that is excited by light with a wavelength around 488nm. The Alexa Fluor 488 probe is used to visualize the cytoskeleton.
Yes, totally different. Papers that use them together usually are looking to show localization of the GFP tagged protein of interest relative to the cytoskeleton.