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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 conditions diameters of curvature [μm] a comments ref.
kinesin-1 carpets
 standard tub, 10-20 μm taxol (after?) b polym. 1-1.4 c waves and curls upon pinning (1)
 standard tub, 50 μM taxol during & after polym.; high MT density (2.5 MTs/μm2) 1-5 loops 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-heptane 1.1 (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 c left-handed supertwist favours CCW rotation of loops; CCW rotation is preserved in spools (4)
 biotin-tub, 10 μm taxol after polym.; SA-linked 1-12.6, mean 3.9
 biotin-tub, 10 μm taxol after polym.; SA-linked 1-5, mean 2.3 up 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/μm2 ca. 2.4-4 highest 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-linked 5.7 (@ 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-linked 18.8 (@ 10.3 μm length), 5.8 (@ 3.4 μm)
 biotin-GMPCPP-tub, no taxol; SA-linked 8.2 (@ 10 μm length), 4.3 (@ 3.4 μm)
 biotin-GTP-tub, 10 μm taxol (after?)b polym.; SA-linked 3.2 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 device 2.7 (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-linked 1.2, mean 3.4 left/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 carpets 1-5.3 and 3.1 smallest 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 taxol straight forming vortices in mm range (12)