  We model the well-known interlinked cascade of Rab GTPases found in
eukaryotic cells by using a network of Markov states to investigate the
universal Thermodynamic Uncertainty Relation for the non-equilibrium system.
First, we prove numerically the TUR in both single Rab species model and the
interlinked two Rab species model. Our results show that when two Rab GTPase
proteins are interlinked at far from equilibrium, the thermodynamic cost and
hence precision is greatly enhanced as compared to single species switching.
This implies that at far from equilibrium, the proteins tries to optimise the
precision of the performance of their biomolecular processes by forming
interlinks in the cascade. Again,our results imply that the interlinked cascade
(or oscillator) can achieve a range of tunable rate constants (or frequencies)
which suggests a means of maintaining its robustness. Lastly, we highlight a
close relation between thermodynamic cost-precision, triangular motifs and
disease dynamics.
