  Molecular transport maintains cellular structures and functions. For example,
lipid and protein diffusion sculpts the dynamic shapes and structures on the
cell membrane that perform essential cellular functions, such as cell
signaling. Temperature variations in thermal equilibrium rapidly change
molecular transport properties. The coefficient of lipid self-diffusion
increases exponentially with temperature in thermal equilibrium, for example.
Hence, in the noisy cellular environment, where temperatures can fluctuate
widely due to local heat generation, maintaining cellular homeostasis through
molecular transport is hard in thermal equilibrium. In this paper, using both
molecular and lattice-based modeling of membrane transport, we show that the
presence of active transport originating from the cell's cytoskeleton can make
the self-diffusion of the molecules on the membrane robust to temperature
fluctuations. The resultant temperature-independence of self-diffusion keeps
the precision of cellular signaling invariant over a broad range of ambient
temperatures, allowing cells to make robust decisions. We have also found that
the Kawasaki algorithm, the widely used model of lipid transport on lattices,
predicts incorrect temperature dependence of lipid self-diffusion in
equilibrium. We propose a new algorithm that correctly captures the equilibrium
properties of lipid self-diffusion and reproduces experimental observations.
