Optimality of spatially inhomogeneous search strategies

Abstract

We consider random search processes alternating stochastically between diffusion and ballistic motion, in which the distribution function of ballistic motion directions varies from point to point in space. The specific space dependence of the directional distribution together with the switching rates between the two modes of motion establishes a spatially inhomogeneous search strategy. We show that the mean first passage times for several standard search problems - narrow escape, reaction partner finding, reaction-escape - can be minimized with a directional distribution that is reminiscent of the spatial organization of the cytoskeleton filaments of cells with a centrosome: radial ballistic transport from center to periphery and back, and ballistic transport in random directions within a concentric shell of thickness ${\Delta }_{\mathrm{opt}}$ along the domain boundary. The results suggest that living cells realize efficient search strategies for various intracellular transport problems economically through a spatial cytoskeleton organization that involves radial microtubules in the central region and only a narrow actin cortex rather than a cell body filled with randomly oriented actin filaments.

9 pages, 6 figures (including supplementary material), published version

References in corpus (5)

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Cited by in corpus (11)

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• Chemokinetic scattering, trapping, and avoidance of active Brownian particles
• Numerical analysis of homogeneous and inhomogeneous intermittent search strategies
• The narrow escape problem in a circular domain with radial piecewise constant diffusivity
• Narrow escape problem in two-shell spherical domains
• Topology-dependent density optima for efficient simultaneous network exploration
• Stochastic 1D search-and-capture as a G/M/c queueing model
• Cytoskeletal filament length controlled dynamic sequestering of intracellular cargo
• Universal Linear Response of First-Passage Kinetics: A Framework for Prediction and Inference