Stochastic kinetics of a single headed motor protein: dwell time distribution of KIF1A

TL;DR

This paper derives analytical expressions for the dwell time distribution of the motor protein KIF1A, providing a theoretical framework that can be tested with single-molecule experiments to better understand its stochastic movement along microtubules.

Contribution

The authors develop an analytical model for dwell time distribution of KIF1A using the NOSC model, including detailed probability densities for conditional dwell times and steps.

Findings

Derived explicit formulas for dwell time distributions.

Calculated probability densities for conditional dwell times.

Predicted distributions can be tested in single-molecule experiments.

Abstract

KIF1A, a processive single headed kinesin superfamily motor, hydrolyzes Adenosine triphosphate (ATP) to move along a filamentous track called microtubule. The stochastic movement of KIF1A on the track is characterized by an alternating sequence of pause and translocation. The sum of the durations of pause and the following translocation defines the dwell time. Using the NOSC model (Nishinari et. al. PRL, {\bf 95}, 118101 (2005)) of individual KIF1A, we systematically derive an analytical expression for the dwell time distribution. More detailed information is contained in the probability densities of the "conditional dwell times" $\tau_{\pm\pm}$ in between two consecutive steps each of which could be forward (+) or backward (-). We calculate the probability densities $\Xi_{\pm\pm}$ of these four conditional dwell times. However, for the convenience of comparison with experimental data, we also present the two distributions $\Xi_{\pm}^{*}$ of the times of dwell before a forward (+) and a backward (-) step. In principle, our theoretical prediction can be tested by carrying out single-molecule experiments with adequate spatio-temporal resolution.