{"format":"molecular-machines.cards","version":1,"updated":"2026-10-01","decks":[{"machine":"dynein","name":"Dynein","count":28,"url":"/learn/cards/dynein.json"}],"cards":[{"id":"dynein-direction","machine":"dynein","kind":"cloze","prompt":"Cytoplasmic dynein carries cargo along microtubules toward the {{minus end}}.","answer":"minus end","explanation":"Kinesin walks the same microtubule tracks the other way, so the two motors pull cargo in a tug of war.","section":"summary","topic":"purpose","sources":["machine:summary","machine:tagline","link:kinesin"],"tags":["direction","transport"],"difficulty":1,"url":"/machines/dynein#summary","cites":[{"source":"machine:summary","machine":"dynein","label":"Summary","section":"summary"},{"source":"machine:tagline","machine":"dynein","label":"Summary","section":"summary"},{"source":"link:kinesin","machine":"dynein","label":"Link to Kinesin","section":"story"}]},{"id":"dynein-activators","machine":"dynein","kind":"qa","prompt":"Alone, human dynein-1 is mostly inactive. Which two partners switch it on?","answer":"Dynactin and a cargo adaptor (such as BICD2).","explanation":"Together they turn dynein into an ultraprocessive motor. The adaptor also links dynein and dynactin to the cargo.","section":"summary","topic":"parts","sources":["machine:summary","component:dynactin","component:cargo adaptor","species:Human dynein-1","ref:mckenney2014"],"tags":["regulation","dynactin"],"difficulty":1,"url":"/machines/dynein#summary","cites":[{"source":"machine:summary","machine":"dynein","label":"Summary","section":"summary"},{"source":"component:dynactin","machine":"dynein","label":"Part: dynactin","section":"summary"},{"source":"component:cargo adaptor","machine":"dynein","label":"Part: cargo adaptor","section":"summary"},{"source":"species:Human dynein-1","machine":"dynein","label":"Human dynein-1","section":"summary"},{"source":"ref:mckenney2014","machine":"dynein","label":"McKenney et al.","section":"sources","anchor":"ref-mckenney2014","href":"https://doi.org/10.1126/science.1254198"}]},{"id":"dynein-ring","machine":"dynein","kind":"qa","prompt":"What forms the ring at the core of each dynein motor domain?","answer":"Six AAA+ domains (AAA1 to AAA6).","explanation":"The AAA+ fold is an ATP-binding module found in many cellular machines. In dynein, all six come in tandem from one heavy chain.","section":"summary","topic":"parts","sources":["stat:AAA+ domains in the ring","evolution:AAA+ family member","evidence:carter2011-six-aaa-domains","ref:uniprotQ14204"],"tags":["aaa","structure"],"difficulty":1,"url":"/machines/dynein#summary","cites":[{"source":"stat:AAA+ domains in the ring","machine":"dynein","label":"Key number: AAA+ domains in the ring","section":"summary"},{"source":"evolution:AAA+ family member","machine":"dynein","label":"AAA+ family member","section":"summary"},{"source":"evidence:carter2011-six-aaa-domains","machine":"dynein","label":"Number of AAA+ domains in the motor ring (Carter AP 2011)","section":"evidence","anchor":"ev-carter2011-six-aaa-domains"},{"source":"ref:uniprotQ14204","machine":"dynein","label":"UniProt Q14204, Cytoplasmic dynein 1 heavy chain 1 (human)","section":"sources","anchor":"ref-uniprotQ14204","href":"https://rest.uniprot.org/uniprotkb/Q14204"}]},{"id":"dynein-main-atp-site","machine":"dynein","kind":"qa","prompt":"Which of dynein's six AAA+ domains is the main site that splits ATP?","answer":"AAA1","explanation":"AAA2 to AAA4 also bind nucleotide, but they tune the cycle rather than drive it.","section":"summary","topic":"parts","sources":["machine:energy","step:ATP binds the rear head"],"tags":["atp","aaa"],"difficulty":2,"url":"/machines/dynein#summary","cites":[{"source":"machine:energy","machine":"dynein","label":"Summary","section":"summary"},{"source":"step:ATP binds the rear head","machine":"dynein","label":"Step: ATP binds the rear head","section":"mechanism"}]},{"id":"dynein-stalk","machine":"dynein","kind":"cloze","prompt":"Dynein's ATPase ring reaches the microtubule through a coiled-coil {{stalk}} about 15 nm long, with the microtubule-binding foot (MTBD) at its tip.","answer":"stalk","explanation":"Ring and foot are 15 nm apart, so signals between them must travel along this rod.","section":"summary","topic":"parts","sources":["stat:Stalk length","component:MTBD","machine:summary","ref:carter2008"],"tags":["stalk","structure"],"difficulty":1,"url":"/machines/dynein#summary","cites":[{"source":"stat:Stalk length","machine":"dynein","label":"Key number: Stalk length","section":"summary"},{"source":"component:MTBD","machine":"dynein","label":"Part: MTBD","section":"summary"},{"source":"machine:summary","machine":"dynein","label":"Summary","section":"summary"},{"source":"ref:carter2008","machine":"dynein","label":"Carter et al.","section":"sources","anchor":"ref-carter2008","href":"https://doi.org/10.1126/science.1164424"}]},{"id":"dynein-step-size","machine":"dynein","kind":"cloze","prompt":"The most frequent step of yeast dynein is {{8 nm}}, close to the spacing of tubulin dimers.","answer":"8 nm","explanation":"Steps vary from 4 to 24 nm, and side and backward steps also occur.","section":"summary","topic":"numbers","sources":["stat:Most frequent step","evidence:reckpeterson2006-step-size","ref:reckpeterson2006"],"tags":["stepping"],"difficulty":1,"url":"/machines/dynein#summary","cites":[{"source":"stat:Most frequent step","machine":"dynein","label":"Key number: Most frequent step","section":"summary"},{"source":"evidence:reckpeterson2006-step-size","machine":"dynein","label":"Step size of the dynein dimer (centre of mass) (Reck-Peterson SL 2006)","section":"evidence","anchor":"ev-reckpeterson2006-step-size"},{"source":"ref:reckpeterson2006","machine":"dynein","label":"Reck-Peterson et al.","section":"sources","anchor":"ref-reckpeterson2006","href":"https://doi.org/10.1016/j.cell.2006.05.046"}]},{"id":"dynein-reverse-direction","machine":"dynein","kind":"qa","prompt":"How did Can and colleagues make yeast dynein walk toward the plus end?","answer":"They changed the angle and the length of its stalk.","explanation":"So stalk geometry sets dynein's direction. All natural dyneins studied so far walk toward the minus end.","section":"summary","topic":"debate","sources":["frontier:Plus-end-directed dynein","evolution:Conserved direction","evidence:can2019-plus-end-dynein","ref:can2019"],"tags":["direction","engineering"],"difficulty":2,"url":"/machines/dynein#summary","cites":[{"source":"frontier:Plus-end-directed dynein","machine":"dynein","label":"Open question: Plus-end-directed dynein","section":"summary"},{"source":"evolution:Conserved direction","machine":"dynein","label":"Conserved direction","section":"summary"},{"source":"evidence:can2019-plus-end-dynein","machine":"dynein","label":"Direction and step size after stalk length and angle changes (Can S 2019)","section":"evidence","anchor":"ev-can2019-plus-end-dynein"},{"source":"ref:can2019","machine":"dynein","label":"Can et al.","section":"sources","anchor":"ref-can2019","href":"https://doi.org/10.1038/s41586-019-0914-z"}]},{"id":"dynein-atp-closes-ring","machine":"dynein","kind":"cloze","prompt":"When ATP binds AAA1, dynein's ring of six AAA+ domains {{closes}}.","answer":"closes","explanation":"ATP binding pulls AAA1 and AAA2 together. Because the six domains form one ring, the closure spreads all the way around it.","section":"mechanism","topic":"cycle","sources":["mechanism:ATP closes the ring","step:ATP binds the rear head","ref:schmidt2015"],"tags":["atp","ring"],"difficulty":1,"url":"/machines/dynein#mechanism","cites":[{"source":"mechanism:ATP closes the ring","machine":"dynein","label":"Step: ATP closes the ring","section":"mechanism"},{"source":"step:ATP binds the rear head","machine":"dynein","label":"Step: ATP binds the rear head","section":"mechanism"},{"source":"ref:schmidt2015","machine":"dynein","label":"Schmidt et al.","section":"sources","anchor":"ref-schmidt2015","href":"https://doi.org/10.1038/nature14023"}]},{"id":"dynein-helix-sliding","machine":"dynein","kind":"cloze","prompt":"Dynein's stalk carries the signal from the ring to the foot by helix {{sliding}}, not by bending.","answer":"sliding","explanation":"As the ring closes, the buttress drags helix CC2 past CC1 by about one turn of helix, and the foot lets go of the microtubule.","section":"mechanism","topic":"cycle","sources":["step:The stalk slides and the foot lets go","mechanism:ATP closes the ring","ref:kon2009"],"tags":["stalk","signalling"],"difficulty":2,"url":"/machines/dynein#mechanism","cites":[{"source":"step:The stalk slides and the foot lets go","machine":"dynein","label":"Step: The stalk slides and the foot lets go","section":"mechanism"},{"source":"mechanism:ATP closes the ring","machine":"dynein","label":"Step: ATP closes the ring","section":"mechanism"},{"source":"ref:kon2009","machine":"dynein","label":"Kon et al.","section":"sources","anchor":"ref-kon2009","href":"https://doi.org/10.1038/nsmb.1555"}]},{"id":"dynein-registry-affinity","machine":"dynein","kind":"qa","prompt":"In dynein's stalk, what does the registry (the alignment) of the two helices CC1 and CC2 control?","answer":"How tightly the foot (MTBD) binds the microtubule.","explanation":"With AAA1 empty, the ring holds the alpha registry and the foot binds tightly. Locking the registry with disulfides traps strong or weak binding.","section":"mechanism","topic":"cycle","sources":["step:The stalk slides and the foot lets go","step:Both heads hold the microtubule","ref:kon2009"],"tags":["stalk","affinity"],"difficulty":2,"url":"/machines/dynein#mechanism","cites":[{"source":"step:The stalk slides and the foot lets go","machine":"dynein","label":"Step: The stalk slides and the foot lets go","section":"mechanism"},{"source":"step:Both heads hold the microtubule","machine":"dynein","label":"Step: Both heads hold the microtubule","section":"mechanism"},{"source":"ref:kon2009","machine":"dynein","label":"Kon et al.","section":"sources","anchor":"ref-kon2009","href":"https://doi.org/10.1038/nsmb.1555"}]},{"id":"dynein-why-linker-bends","machine":"dynein","kind":"qa","prompt":"After ATP binds, why is dynein's linker forced into a bent, primed shape?","answer":"The closed ring clashes with the straight linker; there is no room for it.","explanation":"The bent linker's free end swings across the ring toward AAA2, ready for the next power stroke.","section":"mechanism","topic":"cycle","sources":["mechanism:The ring primes the linker","step:The linker bends: the priming stroke","ref:schmidt2015"],"tags":["linker","priming"],"difficulty":2,"url":"/machines/dynein#mechanism","cites":[{"source":"mechanism:The ring primes the linker","machine":"dynein","label":"Step: The ring primes the linker","section":"mechanism"},{"source":"step:The linker bends: the priming stroke","machine":"dynein","label":"Step: The linker bends: the priming stroke","section":"mechanism"},{"source":"ref:schmidt2015","machine":"dynein","label":"Schmidt et al.","section":"sources","anchor":"ref-schmidt2015","href":"https://doi.org/10.1038/nature14023"}]},{"id":"dynein-power-stroke","machine":"dynein","kind":"cloze","prompt":"When dynein's primed head rebinds the microtubule, phosphate leaves and the linker {{straightens}}: this is the power stroke.","answer":"straightens","explanation":"The energy stored in the primed linker is released while the foot holds the track, so the tail and its cargo move toward the minus end.","section":"mechanism","topic":"cycle","sources":["mechanism:Rebinding triggers the power stroke","step:Phosphate leaves and the linker straightens","ref:chai2025"],"tags":["linker","power-stroke"],"difficulty":1,"url":"/machines/dynein#mechanism","cites":[{"source":"mechanism:Rebinding triggers the power stroke","machine":"dynein","label":"Step: Rebinding triggers the power stroke","section":"mechanism"},{"source":"step:Phosphate leaves and the linker straightens","machine":"dynein","label":"Step: Phosphate leaves and the linker straightens","section":"mechanism"},{"source":"ref:chai2025","machine":"dynein","label":"Chai et al.","section":"sources","anchor":"ref-chai2025","href":"https://doi.org/10.1038/s41594-025-01543-3"}]},{"id":"dynein-slow-step","machine":"dynein","kind":"qa","prompt":"Which step of the dynein cycle appears to be the slow one?","answer":"ADP release from AAA1.","explanation":"Among active human dynein-1 motors off microtubules, most held ADP in an open AAA1 pocket. Microtubule binding opens the pocket wide and speeds ADP release.","section":"mechanism","topic":"cycle","sources":["step:ADP leaves the new lead head","evidence:chai2025-cycle-states","ref:chai2025"],"tags":["adp","kinetics"],"difficulty":3,"url":"/machines/dynein#mechanism","cites":[{"source":"step:ADP leaves the new lead head","machine":"dynein","label":"Step: ADP leaves the new lead head","section":"mechanism"},{"source":"evidence:chai2025-cycle-states","machine":"dynein","label":"Conformational states of the human dynein-1 motor during its cycle (Chai P 2025)","section":"evidence","anchor":"ev-chai2025-cycle-states"},{"source":"ref:chai2025","machine":"dynein","label":"Chai et al.","section":"sources","anchor":"ref-chai2025","href":"https://doi.org/10.1038/s41594-025-01543-3"}]},{"id":"dynein-tension-coordination","machine":"dynein","kind":"qa","prompt":"Dynein's two heads step mostly independently, but they show coordination when far apart. What kind of mechanism does that point to?","answer":"A tension-based mechanism.","explanation":"There is no tight gate between the heads: either head can step, whether it is in front or behind.","section":"mechanism","topic":"cycle","sources":["mechanism:Two heads step loosely","evidence:dewitt2012-interhead-separation","ref:dewitt2012","ref:qiu2012"],"tags":["stepping","coordination"],"difficulty":2,"url":"/machines/dynein#mechanism","cites":[{"source":"mechanism:Two heads step loosely","machine":"dynein","label":"Step: Two heads step loosely","section":"mechanism"},{"source":"evidence:dewitt2012-interhead-separation","machine":"dynein","label":"Distance between the two heads during walking (DeWitt MA 2012)","section":"evidence","anchor":"ev-dewitt2012-interhead-separation"},{"source":"ref:dewitt2012","machine":"dynein","label":"DeWitt et al.","section":"sources","anchor":"ref-dewitt2012","href":"https://doi.org/10.1126/science.1215804"},{"source":"ref:qiu2012","machine":"dynein","label":"Qiu et al.","section":"sources","anchor":"ref-qiu2012","href":"https://doi.org/10.1038/nsmb.2205"}]},{"id":"dynein-stroke-order","machine":"dynein","kind":"qa","prompt":"In the classic dynein cycle, the head rebinds the microtubule before its linker straightens. What did Chai and colleagues see that does not fit this order?","answer":"The linker straightened even in motors that were not bound to microtubules.","explanation":"They propose instead that the cargo moves as the docked linker shifts from AAA4 to AAA5.","section":"mechanism","topic":"debate","sources":["step:Phosphate leaves and the linker straightens","ref:chai2025"],"tags":["linker","power-stroke"],"difficulty":3,"url":"/machines/dynein#mechanism","cites":[{"source":"step:Phosphate leaves and the linker straightens","machine":"dynein","label":"Step: Phosphate leaves and the linker straightens","section":"mechanism"},{"source":"ref:chai2025","machine":"dynein","label":"Chai et al.","section":"sources","anchor":"ref-chai2025","href":"https://doi.org/10.1038/s41594-025-01543-3"}]},{"id":"dynein-mucus-escalator","machine":"dynein","kind":"qa","prompt":"Dynein-driven cilia line your airways. What do they push up toward your throat?","answer":"A thin layer of mucus that traps dust and germs.","explanation":"This mucus escalator moves about 5.5 mm per minute and keeps the lungs clean without you noticing.","section":"story","topic":"purpose","sources":["stop:escalator","fact:D2","story:question","ref:bustamantemarin2017"],"tags":["cilia","lungs"],"difficulty":1,"url":"/machines/dynein#story","cites":[{"source":"stop:escalator","machine":"dynein","label":"Big picture: The mucus escalator","section":"story"},{"source":"fact:D2","machine":"dynein","label":"Speed of the mucus layer: 5.5 mm per minute","section":"story"},{"source":"story:question","machine":"dynein","label":"Big picture","section":"story"},{"source":"ref:bustamantemarin2017","machine":"dynein","label":"Bustamante-Marin 2017","section":"sources","href":"https://doi.org/10.1101/cshperspect.a028241"}]},{"id":"dynein-lung-cilia-count","machine":"dynein","kind":"cloze","prompt":"An adult human lung holds an estimated {{three trillion}} motile cilia, each driven by dynein.","answer":"three trillion","explanation":"Each cilium beats 10 to 20 times a second, which adds up to 0.9 to 1.7 million beats a day.","section":"story","topic":"numbers","sources":["fact:D1","fact:D6","story:summary","ref:bustamantemarin2017"],"tags":["cilia","scale"],"difficulty":2,"url":"/machines/dynein#story","cites":[{"source":"fact:D1","machine":"dynein","label":"Motile cilia in an adult lung: 3 × 10^12","section":"story"},{"source":"fact:D6","machine":"dynein","label":"Beats of one cilium per day: 0.9–1.7 million","section":"story"},{"source":"story:summary","machine":"dynein","label":"Big picture","section":"story"},{"source":"ref:bustamantemarin2017","machine":"dynein","label":"Bustamante-Marin 2017","section":"sources","href":"https://doi.org/10.1101/cshperspect.a028241"}]},{"id":"dynein-sliding-to-bending","machine":"dynein","kind":"qa","prompt":"Dynein arms try to slide one rail of a cilium's axoneme past the next. Why does the cilium bend instead?","answer":"The rails are tied together at the base, so they cannot slide far.","explanation":"Without the base links the rails would just slide apart; tied together, the sliding turns into a bend.","section":"story","topic":"purpose","sources":["stop:sliding","stop:axoneme"],"tags":["cilia","bending"],"difficulty":2,"url":"/machines/dynein#story","cites":[{"source":"stop:sliding","machine":"dynein","label":"Big picture: Sliding becomes bending","section":"story"},{"source":"stop:axoneme","machine":"dynein","label":"Big picture: The axoneme","section":"story"}]},{"id":"dynein-pcd","machine":"dynein","kind":"qa","prompt":"In primary ciliary dyskinesia, airway cilia lack their dynein arms. What happens to the mucus?","answer":"The cilia cannot move, so the mucus does not clear.","explanation":"The disease affects about 1 in 15,000 births, and about half of the people affected have mirrored organs.","section":"story","topic":"purpose","sources":["fact:D13","fact:D14","ref:afzelius1976","ref:bustamantemarin2017"],"tags":["disease","cilia"],"difficulty":1,"url":"/machines/dynein#story","cites":[{"source":"fact:D13","machine":"dynein","label":"Cilia in primary ciliary dyskinesia: Immotile no dynein arms","section":"story"},{"source":"fact:D14","machine":"dynein","label":"Births with primary ciliary dyskinesia: 1 in 15,000 live births","section":"story"},{"source":"ref:afzelius1976","machine":"dynein","label":"Afzelius 1976","section":"sources","href":"https://doi.org/10.1126/science.1084576"},{"source":"ref:bustamantemarin2017","machine":"dynein","label":"Bustamante-Marin 2017","section":"sources","href":"https://doi.org/10.1101/cshperspect.a028241"}]},{"id":"dynein-bimetal-breaks","machine":"dynein","kind":"qa","prompt":"A cilium is like a bimetal strip: two tied layers turn a change in length into a bend. Where does that analogy break down?","answer":"In a cilium, motors actively slide one rail along the next; in a bimetal strip, heat changes the length.","explanation":"The geometry fits, but the cause differs: the dynein arms on one rail walk along the next rail.","section":"story","topic":"purpose","sources":["analogy:A bimetal strip","stop:sliding"],"tags":["analogy","cilia"],"difficulty":2,"url":"/machines/dynein#story","cites":[{"source":"analogy:A bimetal strip","machine":"dynein","label":"Analogy: A bimetal strip","section":"story"},{"source":"stop:sliding","machine":"dynein","label":"Big picture: Sliding becomes bending","section":"story"}]},{"id":"dynein-arms-per-cilium","machine":"dynein","kind":"qa","prompt":"By calculation, about how many outer dynein arms does one airway cilium hold?","answer":"About 2,000 to 2,600.","explanation":"Four outer arms sit in each 96 nm repeat along nine doublets, over 5.5 to 7 µm of length. It is a calculation, not a measured count.","section":"story","topic":"numbers","sources":["fact:D8","fact:D7","fact:D5"],"tags":["cilia","scale"],"difficulty":3,"url":"/machines/dynein#story","cites":[{"source":"fact:D8","machine":"dynein","label":"Outer dynein arms in one cilium: 2,000–2,600","section":"story"},{"source":"fact:D7","machine":"dynein","label":"Layout of the axoneme: 9 + 2 nine doublet rails around a central pair","section":"story"},{"source":"fact:D5","machine":"dynein","label":"Length of one cilium: 6.5–7 µm","section":"story"}]},{"id":"dynein-step-method","machine":"dynein","kind":"qa","prompt":"How did Reck-Peterson and colleagues measure the 8 nm step of yeast dynein?","answer":"They tracked a quantum dot on the dynein tail to a few nanometres (FIONA, TIRF microscopy) at low ATP.","explanation":"Low ATP (4 µM) slowed stepping so single steps could be found: 1342 steps from 27 molecules.","section":"evidence","topic":"numbers","sources":["evidence:reckpeterson2006-step-size","ref:reckpeterson2006"],"tags":["method","stepping"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:reckpeterson2006-step-size","machine":"dynein","label":"Step size of the dynein dimer (centre of mass) (Reck-Peterson SL 2006)","section":"evidence","anchor":"ev-reckpeterson2006-step-size"},{"source":"ref:reckpeterson2006","machine":"dynein","label":"Reck-Peterson et al.","section":"sources","anchor":"ref-reckpeterson2006","href":"https://doi.org/10.1016/j.cell.2006.05.046"}]},{"id":"dynein-head-vs-tail-step","machine":"dynein","kind":"qa","prompt":"A label on one head of yeast dynein moved about 16 to 18 nm per step, twice as far as the tail's 8 nm. Why?","answer":"The two heads take turns stepping.","explanation":"Each head moves about two tubulin dimers each time it steps, while the tail between them advances one dimer per step.","section":"evidence","topic":"numbers","sources":["evidence:reckpeterson2006-step-size","step:It binds 16 nm ahead","ref:reckpeterson2006"],"tags":["stepping","heads"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:reckpeterson2006-step-size","machine":"dynein","label":"Step size of the dynein dimer (centre of mass) (Reck-Peterson SL 2006)","section":"evidence","anchor":"ev-reckpeterson2006-step-size"},{"source":"step:It binds 16 nm ahead","machine":"dynein","label":"Step: It binds 16 nm ahead","section":"mechanism"},{"source":"ref:reckpeterson2006","machine":"dynein","label":"Reck-Peterson et al.","section":"sources","anchor":"ref-reckpeterson2006","href":"https://doi.org/10.1016/j.cell.2006.05.046"}]},{"id":"dynein-superstall","machine":"dynein","kind":"cloze","prompt":"Pulled backward with more than its stall force, yeast dynein walks {{toward the plus end}}.","answer":"toward the plus end","explanation":"In an optical trap at 10 pN it moved about 15 nm/s toward the plus end at any ATP level, and it stepped even with no ATP.","section":"evidence","topic":"numbers","sources":["evidence:gennerich2007-superstall-backward","stat:Stall force, yeast dynein","ref:gennerich2007"],"tags":["force","optical-trap"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:gennerich2007-superstall-backward","machine":"dynein","label":"Backward walking above the stall force (Gennerich A 2007)","section":"evidence","anchor":"ev-gennerich2007-superstall-backward"},{"source":"stat:Stall force, yeast dynein","machine":"dynein","label":"Key number: Stall force, yeast dynein","section":"summary"},{"source":"ref:gennerich2007","machine":"dynein","label":"Gennerich et al.","section":"sources","anchor":"ref-gennerich2007","href":"https://doi.org/10.1016/j.cell.2007.10.016"}]},{"id":"dynein-stall-disagreement","machine":"dynein","kind":"cloze","prompt":"Reported stall forces for full-length yeast dynein differ about {{twofold}}: 7 pN (Gennerich 2007) versus 3.6 pN (Belyy 2016).","answer":"twofold","explanation":"Both values are for full-length yeast dynein. Human dynein-1 alone stalled lower still, at about 2.0 pN.","section":"evidence","topic":"debate","sources":["stat:Stall force, yeast dynein","evidence:gennerich2007-stall-force","evidence:belyy2016-human-dynein-alone","ref:gennerich2007","ref:belyy2016"],"tags":["force","contested"],"difficulty":3,"url":"/machines/dynein#evidence","cites":[{"source":"stat:Stall force, yeast dynein","machine":"dynein","label":"Key number: Stall force, yeast dynein","section":"summary"},{"source":"evidence:gennerich2007-stall-force","machine":"dynein","label":"Stall force of yeast dynein (Gennerich A 2007)","section":"evidence","anchor":"ev-gennerich2007-stall-force"},{"source":"evidence:belyy2016-human-dynein-alone","machine":"dynein","label":"Stall force of human dynein without dynactin or adaptor (Belyy V 2016)","section":"evidence","anchor":"ev-belyy2016-human-dynein-alone"},{"source":"ref:gennerich2007","machine":"dynein","label":"Gennerich et al.","section":"sources","anchor":"ref-gennerich2007","href":"https://doi.org/10.1016/j.cell.2007.10.016"},{"source":"ref:belyy2016","machine":"dynein","label":"Belyy et al.","section":"sources","anchor":"ref-belyy2016","href":"https://doi.org/10.1038/ncb3393"}]},{"id":"dynein-ddb-trap-method","machine":"dynein","kind":"qa","prompt":"How did Belyy and colleagues make their optical trap pull only on complete dynein–dynactin–BICD2 complexes?","answer":"They attached the bead through a GFP tag on the adaptor, BICD2N.","explanation":"These complexes stalled at 4.3 pN, about twice the 2.0 pN of human dynein alone.","section":"evidence","topic":"numbers","sources":["evidence:belyy2016-ddb-stall-force","stat:Stall force, human dynein-dynactin-BICD2","ref:belyy2016"],"tags":["method","force","optical-trap"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:belyy2016-ddb-stall-force","machine":"dynein","label":"Stall force of the dynein-dynactin-BICD2N complex (Belyy V 2016)","section":"evidence","anchor":"ev-belyy2016-ddb-stall-force"},{"source":"stat:Stall force, human dynein-dynactin-BICD2","machine":"dynein","label":"Key number: Stall force, human dynein-dynactin-BICD2","section":"summary"},{"source":"ref:belyy2016","machine":"dynein","label":"Belyy et al.","section":"sources","anchor":"ref-belyy2016","href":"https://doi.org/10.1038/ncb3393"}]},{"id":"dynein-tug-of-war","machine":"dynein","kind":"qa","prompt":"One dynein–dynactin–BICD2 complex was linked to one kinesin-1. How did the pair move?","answer":"The pairs crawled (median 26 nm/s), and about one in five moved toward the minus end.","explanation":"Without dynactin and BICD2N the pairs ran almost as fast as kinesin alone. One activated dynein can hold its own against one kinesin.","section":"evidence","topic":"numbers","sources":["evidence:belyy2016-tug-of-war","frontier:Balanced bidirectional transport","ref:belyy2016"],"tags":["kinesin","force"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:belyy2016-tug-of-war","machine":"dynein","label":"One dynein-dynactin-BICD2N complex against one kinesin-1 (Belyy V 2016)","section":"evidence","anchor":"ev-belyy2016-tug-of-war"},{"source":"frontier:Balanced bidirectional transport","machine":"dynein","label":"Open question: Balanced bidirectional transport","section":"summary"},{"source":"ref:belyy2016","machine":"dynein","label":"Belyy et al.","section":"sources","anchor":"ref-belyy2016","href":"https://doi.org/10.1038/ncb3393"}]},{"id":"dynein-two-dyneins","machine":"dynein","kind":"qa","prompt":"Why do dynein complexes built with the adaptors BICDR1 or HOOK3 pull harder and move faster than those built with BICD2?","answer":"They mostly recruit two dyneins per dynactin.","explanation":"Complexes with one active dynein and one tail that cannot walk were as slow as BICD2 complexes. With BICDR1 the stall force (6.5 pN) beat kinesin-1 (5.7 pN).","section":"evidence","topic":"numbers","sources":["evidence:urnavicius2018-two-dynein-force","evidence:urnavicius2018-two-dynein-speed","ref:urnavicius2018"],"tags":["dynactin","force","speed"],"difficulty":2,"url":"/machines/dynein#evidence","cites":[{"source":"evidence:urnavicius2018-two-dynein-force","machine":"dynein","label":"Stall force with one or two dyneins per dynactin (Urnavicius L 2018)","section":"evidence","anchor":"ev-urnavicius2018-two-dynein-force"},{"source":"evidence:urnavicius2018-two-dynein-speed","machine":"dynein","label":"Speed with one or two dyneins per dynactin (Urnavicius L 2018)","section":"evidence","anchor":"ev-urnavicius2018-two-dynein-speed"},{"source":"ref:urnavicius2018","machine":"dynein","label":"Urnavicius et al.","section":"sources","anchor":"ref-urnavicius2018","href":"https://doi.org/10.1038/nature25462"}]}]}