Abstract:
:Diffusion in the plasma membrane of living cells is often found to display anomalous dynamics. However, the mechanism underlying this diffusion pattern remains highly controversial. Here, we study the physical mechanism underlying Kv2.1 potassium channel anomalous dynamics using single-molecule tracking. Our analysis includes both time series of individual trajectories and ensemble averages. We show that an ergodic and a nonergodic process coexist in the plasma membrane. The ergodic process resembles a fractal structure with its origin in macromolecular crowding in the cell membrane. The nonergodic process is found to be regulated by transient binding to the actin cytoskeleton and can be accurately modeled by a continuous-time random walk. When the cell is treated with drugs that inhibit actin polymerization, the diffusion pattern of Kv2.1 channels recovers ergodicity. However, the fractal structure that induces anomalous diffusion remains unaltered. These results have direct implications on the regulation of membrane receptor trafficking and signaling.
journal_name
Proc Natl Acad Sci U S Aauthors
Weigel AV,Simon B,Tamkun MM,Krapf Ddoi
10.1073/pnas.1016325108subject
Has Abstractpub_date
2011-04-19 00:00:00pages
6438-43issue
16eissn
0027-8424issn
1091-6490pii
1016325108journal_volume
108pub_type
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