  Trajectories of endosomes inside living eukaryotic cells are highly
heterogeneous in space and time and diffuse anomalously due to a combination of
viscoelasticity, caging, aggregation and active transport. Some of the
trajectories display switching between persistent and anti-persistent motion
while others jiggle around in one position for the whole measurement time. By
splitting the ensemble of endosome trajectories into slow moving sub-diffusive
and fast moving super-diffusive endosomes, we analyzed them separately. The
mean squared displacements and velocity auto-correlation functions confirm the
effectiveness of the splitting methods. Applying the local analysis, we show
that both ensembles are characterized by a spectrum of local anomalous
exponents and local generalized diffusion coefficients. Slow and fast endsomes
have exponential distributions of local anomalous exponents and power law
distributions of generalized diffusion coefficients. This suggests that
heterogeneous fractional Brownian motion is an appropriate model for both fast
and slow moving endosomes. This article is part of a Special Issue entitled:
"Recent Advances In Single-Particle Tracking: Experiment and Analysis" edited
by Janusz Szwabi\'nski and Aleksander Weron.
