Exchange of microtubule molecular motors during melanosome transport in Xenopus laevis melanophores is triggered by collisions with intracellular obstacles

Authors
Bruno, Luciana; Echarte, Maria Mercedes; Levi, Valeria
Publication Year
2008
Language
English
Format
article
Status
Published version
Description
The observation that several cargoes move bidirectionally along microtubules in vivo raised the question regarding how molecular motors with opposed polarity coordinate during transport. In this work, we analyzed the switch of microtubule motors during the transport of melanosomes in Xenopus melanophores by registering trajectories of these organelles moving along microtubules using a fast and precise tracking method. We analyzed in detail the intervals of trajectories showing reversions in the original direction of transport and processive motion in the opposite direction for at least 250 nm. In most of the cases, the speed of the melanosome before the reversion slowly decreases with time approaching zero then, the organelle returns over the same path moving initially at a very high speed and slowing down with time. These results could be explained according to a model in which reversions are triggered by an elastic collision of the cargo with obstacles in the cytosol. This interaction generates a force opposed to the movement of the motor-driven organelle increasing the probability of detaching the active motors from the track. The model can explain reversions in melanosome trajectories as well as other characteristics of in vivo transport along microtubules observed by other authors. Our results suggest that the crowded cytoplasm plays a key role in regulating the coordination of microtubules-dependent motors. © 2008 Humana Press Inc.
Fil: Bruno, Luciana. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina
Fil: Echarte, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina
Fil: Levi, Valeria. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina
Subject
COORDINATION
MELANOSOME TRANSPORT
MICROTUBULE MOLECULAR MOTORS
XENOPUS MELANOPHORES
Otras Ciencias Biológicas
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/62182