Mechanical communication between microtubule motors

DE ROSSI, MARÍA CECILIA; WETZLER, DIANA; BENSEÑOR, LORENA; DE ROSSI, MARÍA EMILIA; SUED, MARIELA; RODRÍGUEZ, DANIELA; GELFAND, VLADIMIR; BRUNO, LUCIANA; LEVI, VALERIA

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

Molecular motors transport a wide variety of cellular cargoes positioning them in the cytoplasm with high spatial?temporal precision. In particular, microtubule-dependent-motors, dynein and kinesin, drive organelles bi-directionally; dynein transports cargoes toward the minus end of the microtubule whereas kinesin moves in the opposed direction. Therefore, these opposed-polarity motors compete with each other to determine the final direction of motion. In this work, we explore the interplay of the opposed polarity motors kinesin-1 and cytoplasmic dynein during peroxisome transport along microtubules in Drosophila S2 cells. Using single particle tracking, we registered fluorescent peroxisomes trajectories with nanometer accuracy and millisecond time resolution to extract quantitative information on the bidirectional motion of organelles. We computed the distributions of run length and speeds. These last data were statistically analyzed with a Gaussian functions mixture model following the Akaike information criterion. Transport performance was studied in cells expressing a slow chimeric plus-end directed motor or the kinesin heavy chain. We also analyzed the influence of peroxisomes membrane fluidity in methyl-β-ciclodextrin treated cells. The experimental data was confronted with numerical simulations of two well-established tug of war scenarios. Our results support the existence of a crosstalk between opposed-polarity motor teams. Moreover, the slowest teams seem to mechanically communicate with each other through the membrane to trigger transport.