Cargos Rotate at Microtubule Intersections during Intracellular Trafficking

Journal Article · 19 June 2018 · Biophysical Journal

DOI: https://doi.org/10.1016/j.bpj.2018.05.010 · OSTI ID:1527036

Gao, Yuan ^[1]; Anthony, Stephen Michael ^[2]; Yu, Yanqi ^[1]; Yi, Yi ^[1]; Yu, Yan ^[1]

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1. Indiana Univ., Bloomington, IN (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Here, intracellular cargos are transported by molecular motors along actin and microtubules, but how their dynamics depends on the complex structure of the cytoskeletal network remains unclear. In this study, we investigated this longstanding question by measuring simultaneously the rotational and translational dynamics of cargos at microtubule intersections in living cells. We engineered two-faced particles that are fluorescent on one hemisphere and opaque on the other and used their optical anisotropy to report the rotation of cargos. We show that cargos undergo brief episodes of unidirectional and rapid rotation while pausing at microtubule intersections. Probability and amplitude of the cargo rotation depend on the geometry of the intersecting filaments. The cargo rotation is not random motion due to detachment from microtubules, as revealed by statistical analyses of the translational and rotational dynamics. Instead, it is an active rotation driven by motor proteins. Although cargos are known to pause at microtubule intersections, this study reveals a different dimension of dynamics at this seemingly static state and, more importantly, provides direct evidence showing the correlation between cargo rotation and the geometry of underlying microtubule intersections.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000; NA0003525
• OSTI ID: 1527036
• Alternate ID(s): OSTI ID: 1466757; OSTI ID: 1495259
• Report Number(s): SAND-2018-8863J; 667024
• Journal Information: Biophysical Journal, Vol. 114, Issue 12; ISSN 0006-3495
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English