Fig. 1: EEA1 undergoes a Rab5-dependent flexibility transition that can be measured using FCS experiments.
From: Two-component molecular motor driven by a GTPase cycle
Binding of the Rab5(GTP) to EEA1 triggers a transition of the EEA1 molecule from a rigid, extended state to a more flexible, collapsed state. a, Sketch depicting the collapsed/extended states of EEA1 on binding/unbinding to the active/inactive forms of Rab5. b, Doubly tagged (Alexa 488 and 647) EEA1 molecules are used in the dcFCCS experimental setup to measure the dynamics of a single end of the molecules in solution. The time series of the fluorescence intensity fluctuations within the confocal volume is used to quantify the dynamics of molecular motion. c,d, Dynamics in solution for EEA1 alone (blue) and when mixed with Rab5(GTP) (red) are quantified by the MSD plotted over lag time τ (c) and the local scaling exponent α of the MSD (d). The black solid and dashed lines represent scaling exponents α = 3/4 and α = 2/3, respectively, corresponding to regimes where the persistence length of EEA1 is comparable with its contour length, that is, extended and smaller than the contour length that is collapsed. The solid blue (EEA1) and red (EEA1+Rab5(GTP)) lines represent fits to the experimental data using equation (1).
