Figure 8 : The cellular interior appears as a porous medium formed by random obstacles.

From: Retrieving the intracellular topology from multi-scale protein mobility mapping in living cells

Figure 8

The correlation length λ for the distance between obstacles ‘sensed’ by a given protein is derived from the time dependence of its diffusion coefficient (Fig. 5).The parameter χ~15 nm is the estimated throat size of small pores that confine regions in the nucleus where GFP5 (hydrodynamic radius rH≈7.9 nm) is trapped while GFP3 (rH≈5.5 nm) remains mobile. Drug treatment induced structural changes as depicted on the right side of the scheme. Disassembly of cytoplasmic filaments resulted in a moderate increase of GFP3 mobility (Fig. 6, Table 2). In contrast, chromatin decondensation increased GFP3 mobility considerably (Fig. 7a,b, Table 2). Thus, chromatin is the major obstacle in the nucleus, whereas in the cytoplasm the cytoskeleton represents only one obstacle among others.