Intracellular transport is vital for the proper functioning and survival of a
cell. Cargo (proteins, vesicles, organelles, etc.) is transferred from its
place of creation to its target locations via molecular motor assisted
transport along cytoskeletal filaments. The transport efficiency is strongly
affected by the spatial organization of the cytoskeleton, which constitutes an
inhomogeneous, complex network. In cells with a centrosome microtubules grow
radially from the central microtubule organizing center towards the cell
periphery whereas actin filaments form a dense meshwork, the actin cortex,
underneath the cell membrane with a broad range of orientations. The emerging
ballistic motion along filaments is frequently interrupted due to constricting
intersection nodes or cycles of detachment and reattachment processes in the
crowded cytoplasm. In order to investigate the efficiency of search strategies
established by the cell's specific spatial organization of the cytoskeleton we
formulate a random velocity model with intermittent arrest states. With
extensive computer simulations we analyze the dependence of the mean first
passage times for narrow escape problems on the structural characteristics of
the cytoskeleton, the motor properties and the fraction of time spent in each
state. We find that an inhomogeneous architecture with a small width of the
actin cortex constitutes an efficient intracellular search strategy.Comment: 14 pages, 9 figure
