Transport driven by microtubule molecular motors depends on the cargoes size

M. C. DE ROSSI; L. BRUNO; D. WETZLER; M. DESPÓSITO; V. LEVI

Mendoza

Congreso; 95a Reunión Nacional de Física AFA; 2010

Asociación Física Argentina

Molecular motors are among the most important proteins responsible for the intracellular transport. The complex structures of these proteins allowthem to bind different cargoes which are then transported along cytoskeletal filaments system toward their final destination. There are two types of active transport systems which depend on microtubules and actin filaments. In this work, we focused in the microtubule-dependent transport in Xenopuslaevis melanophores. These cells contain pigmented organelles called melanosomes which are transported along microtubules by the action of cytoplasmic dynein and kinesn-2. Although molecular motors allow these organelles to move within melanophores, the cytoplasm viscoelastic properties affect the organelle motility in not completely known ways. In this work,we use single particle tracking (SPT) to explore the dependence of the in vivo dynamics of microtubule-dependent motors on the size of the transported melanosomes. The data showed that small organelles, which are supposed to experience a smaller drag force, are transported less efficiently. These data were interpreted according to an new model that can explain the local influence of the cytoplasm environment on melanosome motion.