Figure 1.

New lines of development concerning the use of genetically encoded FPs as inert tracers of the intracellular environment encompass: (a) the development of new fluorescence-based optical microscopy tools with increased spatiotemporal resolution; (b) the rational engineering of new inert tracers with tunable size, increased photostability and brightness; (c) the effort to model in silico the behavior of inert tracers within the intracellular environment; (d) the use of new strategies to grab the behavior of inert tracers in dynamic subcellular nanosystems, such as organelles, transport vesicles, cellular protrusions, etc.