Intramolecular Strain Coordinates Kinesin Stepping Behavior along Microtubules

Abstract

SUMMARY Kinesin advances 8 nm along a microtubule per ATP hydrolyzed, but the mechanism responsible for coordinating the enzymatic cycles of kinesin’s two identical motor domains remains unresolved. Here, we have tested whether such coordination is mediated by intramolecular tension generated by the “neck linkers”, mechanical elements that span between the motor domains. When tension is reduced by extending the neck linkers with artificial peptides, the coupling between ATP hydrolysis and forward stepping is impaired and motor’s velocity decreases as a consequence. However, speed recovers to nearly normal levels when external tension is applied by an optical trap. Remarkably, external load also induces bidirectional stepping of an immotile kinesin that lacks its mechanical element (neck linker) and fuel (ATP). Our results indicate that the kinesin motor domain senses and responds to strain in a manner that facilitates its plus-end-directed stepping and communication between its two motor domains.

The Kinesin-8 Kip3 Switches Protofilaments in a Sideward Random Walk Asymmetrically Biased by Force

“…Microtubules consist of circularly arranged protein chains, socalled protofilaments, assembled of a/b-tubulin dimers (1). Kinesin-1 tracks a single protofilament (6)(7)(8), seldom switching between them (9,10). Sideward motion of other motors has been detected via rotations of filaments driven by multiple motors in gliding assays and by off-axis movement of motor-attached microspheres or quantum dots used as tracking probes.…”

“…Sideward motion of other motors has been detected via rotations of filaments driven by multiple motors in gliding assays and by off-axis movement of motor-attached microspheres or quantum dots used as tracking probes. Probe and microtubule rotations imply torque generation for all cytoskeletal motors: myosin (11), dynein (9,(12)(13)(14)(15)(16)(17) and kinesin (kinesin-1 monomers (18) and dimers (10), kinesin-2 (19,20), kinesin-5 (21), kinesin-8 (16,22), and kinesin-14 (23)). Occasional directed sideward steps-as suggested for kinesin-8-may explain microtubule rotations of motor-ensemble gliding assays (22) or the spiralling motion of multimotor-coated microspheres around microtubules (20).…”

Characterization of kinesin-like proteins in silkworm posterior silkgland cells

“…It contains an N-terminal motor domain, an internal coiled-coil region, and a C-terminal cargo-binding domain (CBD). It moves along microtubules in a 'hand-over-hand' mechanism [4], with each step gated by adenosine triphosphate hydrolysis [5]. Kinesin-2 transports protein complexes [6], Kinesin-13 regulates microtubule dynamics by serving as a microtubule depolymerase [7][8][9], while Kinesin-14 organizes microtubules into parallel bundles and facilitates spindle assembly in mitosis [10][11][12][13].…”

Walking motion of an overdamped active particle in a ratchet potential

“…One of the interesting observations is the backward moonwalking of kinesin [25,26,[28][29][30][31][32][33][34] under a backward load much larger than the stall force. There are reports that backward steps are related to ATP synthesis [33,35] or ATP hydrolysis [31][32][33][34].…”

“…Conventional kinesin, kinesin-1, walks processively along a microtubule toward the plus end (defined as 'forward') [13][14][15] generating 6-8 pN per step [16] by consuming one adenosine-triphosphate (ATP) [17,18] and transports vesicles and organelles [19][20][21][22][23][24][25][26][27][28]. One of the interesting observations is the backward moonwalking of kinesin [25,26,[28][29][30][31][32][33][34] under a backward load much larger than the stall force.…”