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bioRxiv · 10.1101/557611

MAP7 recruits kinesin-1 to microtubules to direct organelle transport

Chaudhary, A. R.·Lu, H.·Krementsova, E. B.·Bookwalter, C. S.·Trybus, K. M.·Hendricks, A. G.
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Abstract

Microtubule-associated proteins (MAPs) play well-characterized roles in regulating microtubule polymerization, dynamics, and organization. In addition, MAPs control trans-port along microtubules by regulating the motility of kinesin and dynein. MAP7 (ensconsin, E-MAP-115) is a ubiquitous MAP that organizes the microtubule cytoskeleton in mitosis and neuronal branching. MAP7 also promotes the interaction of kinesin-1 with microtubules. We expressed and purified full-length kinesin-1 and MAP7 in Sf9 cells. In single-molecule motiity assays, MAP7 recruits kinesin-1 to microtubules, increasing the frequency of both diffusive and processive runs. Optical trapping assays on beads transported by single and teams of kinesin-1 motors indicate that MAP7 increases the relative binding rate of kinesin-1 and the number of motors simultaneously engaged in ensembles. To examine the role of MAP7 in regulating bidirectional transport, we isolated late phagosomes along with their native set of kinesin-1, kinesin-2, and dynein motors. Bidirectional cargoes exhibit a clear shift towards plus-end directed motility on MAP7-decorated microtubules due to increased forces exerted by kinesin teams. Collectively, our results indicate that MAP7 enhances kinesin-1 recruitment to microtubules and targets organelle transport to the plus end.

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Chaudhary, A. R., Lu, H., Krementsova, E. B., Bookwalter, C. S., Trybus, K. M., Hendricks, A. G.. 2019-02-21. MAP7 recruits kinesin-1 to microtubules to direct organelle transport. https://doi.org/10.1101/557611

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