Skip to main content

Table 3 MT loop or spool formation in gliding assays under different conditions. Footnotes: a) Primarily the lower range of mentioned diameters is listed; b) not clear from experimental section; c) measured from images. Abbreviations: CW, clockwise; CCW, counter-clockwise; polym, polymerisation; SA, streptavidin; tub, tubulin. References: (1) [126], (2) [134], (3) [138], (4) [137], (5) [130], (6) [135], (7) [136], (8) [414], (9) [133], (10) [132], (11) [415], (12) [121]. Note that a number of mathematical models were put forward to describe loop or spool dynamics in gliding assays [141, 156, 157, 414, 416, 417]

From: The model of local axon homeostasis - explaining the role and regulation of microtubule bundles in axon maintenance and pathology

experimental conditionsdiameters of curvature [μm] acommentsref.
kinesin-1 carpets
 standard tub, 10-20 μm taxol (after?) b polym.1-1.4 cwaves and curls upon pinning(1)
 standard tub, 50 μM taxol during & after polym.; high MT density (2.5 MTs/μm2)1-5loops form through collision; loop duration frequently >5 min; strong increase in loops at high MT concentration; decreasing loop radius with increasing contour(2)
 rhodamine-tub, 10 μm taxol after polym.; exposing to air bubble or n-heptane1.1 (heptane), 1.8 (air)MTs become reversibly unstable in non-polar conditions: 50% of MTs form loops as long as close to air bubble; effect absolutely requires kinesins(3)
 rhodamine-tub, 10 μM taxol after polym.2.5-3.75 cleft-handed supertwist favours CCW rotation of loops; CCW rotation is preserved in spools(4)
 biotin-tub, 10 μm taxol after polym.; SA-linked1-12.6, mean 3.9
 biotin-tub, 10 μm taxol after polym.; SA-linked1-5, mean 2.3up to 25 μm long straight bundles; pinning of tip induces spools or fishtailing; occasional “unspooling” events(5)
 biotin-tub, 10 μm taxol after polym.; SA-linked; 1600, 870, 270 and 90 kinesins/μm2ca. 2.4-4highest spool density & lowest spool diameter @ highest kinesin density; pinning as main cause for spool formation(6)
 biotin-GTP-tub, 10 μm taxol after polym.; SA-linked5.7 (@ 10.8 μm length), 3 (@ 3,7 μm)spool diameters increase with MT length per condition; spool diameters: GMP-MTs (taxol) < GMPCPP-MTs (no taxol) < GMPCPP-MTs (taxol)(7)
 biotin-GMPCPP-tub, 10 μm taxol after polym.; SA-linked18.8 (@ 10.3 μm length), 5.8 (@ 3.4 μm)
 biotin-GMPCPP-tub, no taxol; SA-linked8.2 (@ 10 μm length), 4.3 (@ 3.4 μm)
 biotin-GTP-tub, 10 μm taxol (after?)b polym.; SA-linked3.2 μm (@ 6μm length)live imaging: pinning & collisions (simultaneous sticking) cause spool formation; spool formation is not activated by a Brownian ratchet type process(8)
 biotin-tub, 10 μm taxol after polym.; SA-linked; microfluidic device2.7 (pinning), 6.2 (collisions)live imaging: pinning & collisions (simultaneous sticking) cause spools of different diameters; pinning more frequent in flow cells than microfluidic device(9)
 biotin-tub, (taxol?)b polym.; SA-quantum dot-linked1.2, mean 3.4left/right-handed super-twist: CCW/CW rotation; rings form intertwined wreath-like structures; tendency to disassemble involving MT breakage, kinesins pulling (blocked by AMP-PNP), counteracted by SA (enhanced by biotin)(10)
 biotin-tub, 10 μm taxol after polym.; SA-quantum dot-linked; patterned kinesin carpets1-5.3 and 3.1smallest spool diameters on constrained carpets: 1-5.3 μm on 5 μm stripes, 3.1 μm on 2 μm wide squares(11)
axonemal dynein carpet
 Cy3-tub, 10μM taxolstraightforming vortices in mm range(12)
\