Dynactin Explained

Dynactin is a 23 subunit protein complex that acts as a co-factor for the microtubule motor cytoplasmic dynein-1. It is built around a short filament of actin related protein-1 (Arp1).[1] [2]

Discovery

Dynactin was identified as an activity that allowed purified cytoplasmic dynein to move membrane vesicles along microtubules in vitro.[3] It was shown to be a multiprotein complex and named "dynactin" because of its role in dynein activation.[4]

The main features of dynactin were visualized by quick-freeze, deep-etch, rotary shadow electron microscopy. It appears as a short filament, 37-nm in length, which resembles F-actin, plus a thinner, laterally oriented arm.[5] Antibody labelling was used to map the location of the dynactin subunits.[6]

Structure

Dynactin consists of three major structural domains: (1) sidearm-shoulder: DCTN1/p150Glued, DCTN2/p50/dynamitin, DCTN3/p24/p22;(2)the Arp1 filament: ACTR1A/Arp1/centractin, actin, CapZ; and (3) the pointed end complex: Actr10/Arp11, DCTN4/p62, DCTN5/p25, and DCTN6/p27.

A 4Å cryo-EM structure of dynactin [7] revealed that its filament contains eight Arp1 molecules, one β-actin and one Arp11. In the pointed end complex p62/DCTN4 binds to Arp11 and β-actin and p25 and p27 bind both p62 and Arp11. At the barbed end the capping protein (CapZαβ) binds the Arp1 filament in the same way that it binds actin, although with more charge complementarity, explaining why it binds dynactin more tightly than actin.[8]

The shoulder contains two copies of p150Glued/DCTN1, four copies of p50/DCTN2 and two copies of p24/DCTN3. These proteins form long bundles of alpha helices, which wrap over each other and contact the Arp1 filament. The N-termini of p50/DCTN2 emerge from the shoulder and coat the filament, providing a mechanism for controlling the filament length. The C-termini of the p150Glued/DCTN1 dimer are embedded in the shoulder, whereas the N-terminal 1227 amino acids form the projecting arm. The arm consists of an N-terminal CAPGly domain which can bind the C-terminal tails of microtubules and the microtubule plus end binding protein EB1. This is followed by a basic region, also involved in microtubule binding, a folded-back coiled coil (CC1), the intercoiled domain (ICD) and a second coiled coil domain (CC2). The p150Glued arm can dock into against the side of the Arp1 filament and pointed end complex.

DCTN2 (dynamitin) is also involved in anchoring microtubules to centrosomes and may play a role in synapse formation during brain development.[9] Arp1 has been suggested as the domain for dynactin binding to membrane vesicles (such as Golgi or late endosome) through its association with β-spectrin.[10] [11] [12] [13] The pointed end complex (PEC) has been shown to be involved in selective cargo binding. PEC subunits p62/DCTN4 and Arp11/Actr10 are essential for dynactin complex integrity and dynactin/dynein targeting to the nuclear envelope before mitosis.[14] [15] [16] Actr10 along with Drp1 (Dynamin related protein 1) have been documented as vital to the attachment of mitochondria to the dynactin complex.[17] Dynactin p25/DCTN5 and p27/DCTN6 are not essential for dynactin complex integrity, but are required for early and recycling endosome transport during the interphase and regulation of the spindle assembly checkpoint in mitosis.[18] [19]

Interaction with dynein

Dynein and dynactin were reported to interact directly by the binding of dynein intermediate chains with p150Glued.[20] The affinity of this interaction is around 3.5μM.[21] Dynein and dynactin do not run together in a sucrose gradient, but can be induced to form a tight complex in the presence of the N-terminal 400 amino acids of Bicaudal D2 (BICD2), a cargo adaptor that links dynein and dynactin to Golgi derived vesicles.[22] In the presence of BICD2, dynactin binds to dynein and activates it to move for long distances along microtubules.[23] [24]

A cryo-EM structure of dynein, dynactin and BICD2 showed that the BICD2 coiled coil runs along the dynactin filament. The tail of dynein also binds to the Arp1 filament, sitting in the equivalent site that myosin uses to bind actin. The contacts between the dynein tail and dynactin all involve BICD, explaining why it is needed to bring them together. The dynein/dynactin/BICD2 (DDB) complex has also been observed, by negative stain EM, on microtubules. This shows that the cargo (Rab6) binding end of BICD2 extends out through the pointed end complex at the opposite end away from the dynein motor domains.[25]

Functions

Dynactin is often essential for dynein activity[1] [3] and can be thought of as a "dynein receptor"[20] that modulates binding of dynein to cell organelles which are to be transported along microtubules.[26] [27] Dynactin also enhances the processivity of cytoplasmic dynein[28] and kinesin-2 motors.[29] Dynactin is involved in various processes like chromosome alignment and spindle organization[30] in cell division.[31] Dynactin contributes to mitotic spindle pole focusing through its binding to nuclear mitotic apparatus protein (NuMA).[32] [33] Dynactin also targets to the kinetochore through binding between DCTN2/dynamitin and zw10 and has a role in mitotic spindle checkpoint inactivation.[34] [35] During prometaphase, dynactin also helps target polo-like kinase 1 (Plk1) to kinetochores through cyclin dependent kinase 1 (Cdk1)-phosphorylated DCTN6/p27, which is involved in proper microtubule-kinetochore attachment and recruitment of spindle assembly checkpoint protein Mad1.[19] In addition, dynactin has been shown to play an essential role in maintaining nuclear position in Drosophila,[36] zebrafish[37] or in different fungi.[38] [39] Dynein and dynactin concentrate on the nuclear envelope during the prophase and facilitate nuclear envelope breakdown via its DCTN4/p62 and Arp11 subunits.[16] [14] Dynactin is also required for microtubule anchoring at centrosomes and centrosome integrity.[40] Destabilization of the centrosomal pool of dynactin also causes abnormal G1 centriole separation and delayed entry into S phase, suggesting that dynactin contributes to the recruitment of important cell cycle regulators to centrosomes.[41] In addition to transport of various organelles in the cytoplasm, dynactin also links kinesin II to organelles.[42]

See also

Further reading

Notes and References

  1. Schroer TA . Dynactin . Annual Review of Cell and Developmental Biology . 20 . 759–79 . November 2004 . 15473859 . 10.1146/annurev.cellbio.20.012103.094623 .
  2. Carter AP, Diamant AG, Urnavicius L . How dynein and dynactin transport cargos: a structural perspective . Current Opinion in Structural Biology . 37 . 62–70 . April 2016 . 26773477 . 10.1016/j.sbi.2015.12.003 .
  3. Schroer TA, Sheetz MP . Two activators of microtubule-based vesicle transport . The Journal of Cell Biology . 115 . 5 . 1309–18 . December 1991 . 1835460 . 2289226 . 10.1083/jcb.115.5.1309 .
  4. Gill SR, Schroer TA, Szilak I, Steuer ER, Sheetz MP, Cleveland DW . Dynactin, a conserved, ubiquitously expressed component of an activator of vesicle motility mediated by cytoplasmic dynein . The Journal of Cell Biology . 115 . 6 . 1639–50 . December 1991 . 1836789 . 2289205 . 10.1083/jcb.115.6.1639 .
  5. Schafer DA, Gill SR, Cooper JA, Heuser JE, Schroer TA . Ultrastructural analysis of the dynactin complex: an actin-related protein is a component of a filament that resembles F-actin . The Journal of Cell Biology . 126 . 2 . 403–12 . July 1994 . 7518465 . 2200042 . 10.1083/jcb.126.2.403 .
  6. Eckley DM, Gill SR, Melkonian KA, Bingham JB, Goodson HV, Heuser JE, Schroer TA . Analysis of dynactin subcomplexes reveals a novel actin-related protein associated with the arp1 minifilament pointed end . The Journal of Cell Biology . 147 . 2 . 307–20 . October 1999 . 10525537 . 2174220 . 10.1083/jcb.147.2.307 .
  7. Urnavicius L, Zhang K, Diamant AG, Motz C, Schlager MA, Yu M, Patel NA, Robinson CV, Carter AP . The structure of the dynactin complex and its interaction with dynein . Science . 347 . 6229 . 1441–1446 . March 2015 . 25814576 . 4413427 . 10.1126/science.aaa4080 . 2015Sci...347.1441U .
  8. Cheong FK, Feng L, Sarkeshik A, Yates JR, Schroer TA . Dynactin integrity depends upon direct binding of dynamitin to Arp1 . Molecular Biology of the Cell . 25 . 14 . 2171–80 . July 2014 . 24829381 . 4091830 . 10.1091/mbc.E14-03-0842 .
  9. Uetake Y, Terada Y, Matuliene J, Kuriyama R . Interaction of Cep135 with a p50 dynactin subunit in mammalian centrosomes . Cell Motility and the Cytoskeleton . 58 . 1 . 53–66 . May 2004 . 14983524 . 10.1002/cm.10175 .
  10. Holleran EA, Tokito MK, Karki S, Holzbaur EL . Centractin (ARP1) associates with spectrin revealing a potential mechanism to link dynactin to intracellular organelles . The Journal of Cell Biology . 135 . 6 Pt 2 . 1815–29 . December 1996 . 8991093 . 2133946 . 10.1083/jcb.135.6.1815 .
  11. Holleran EA, Ligon LA, Tokito M, Stankewich MC, Morrow JS, Holzbaur EL . beta III spectrin binds to the Arp1 subunit of dynactin . The Journal of Biological Chemistry . 276 . 39 . 36598–605 . September 2001 . 11461920 . 10.1074/jbc.M104838200 . free .
  12. Muresan V, Stankewich MC, Steffen W, Morrow JS, Holzbaur EL, Schnapp BJ . Dynactin-dependent, dynein-driven vesicle transport in the absence of membrane proteins: a role for spectrin and acidic phospholipids . Molecular Cell . 7 . 1 . 173–83 . January 2001 . 11172722 . 10.1016/S1097-2765(01)00165-4 . free .
  13. Johansson M, Rocha N, Zwart W, Jordens I, Janssen L, Kuijl C, Olkkonen VM, Neefjes J . Activation of endosomal dynein motors by stepwise assembly of Rab7-RILP-p150Glued, ORP1L, and the receptor betalll spectrin . The Journal of Cell Biology . 176 . 4 . 459–71 . February 2007 . 17283181 . 2063981 . 10.1083/jcb.200606077 .
  14. Salina D, Bodoor K, Eckley DM, Schroer TA, Rattner JB, Burke B . Cytoplasmic dynein as a facilitator of nuclear envelope breakdown . Cell . 108 . 1 . 97–107 . January 2002 . 11792324 . 10.1016/S0092-8674(01)00628-6 . 18798861 . free .
  15. Zhang J, Wang L, Zhuang L, Huo L, Musa S, Li S, Xiang X . Arp11 affects dynein-dynactin interaction and is essential for dynein function in Aspergillus nidulans . Traffic . 9 . 7 . 1073–87 . July 2008 . 18410488 . 2586032 . 10.1111/j.1600-0854.2008.00748.x .
  16. Yeh TY, Quintyne NJ, Scipioni BR, Eckley DM, Schroer TA . Dynactin's pointed-end complex is a cargo-targeting module . Molecular Biology of the Cell . 23 . 19 . 3827–37 . October 2012 . 22918948 . 3459859 . 10.1091/mbc.E12-07-0496 .
  17. Catherine Drerup, Amy Herbert, Kelly Monk, Alex Nechiporuk, "Regulation of mitochondria-dynactin interaction and mitochondrial retrograde transport in axons"
  18. Zhang J, Yao X, Fischer L, Abenza JF, Peñalva MA, Xiang X . The p25 subunit of the dynactin complex is required for dynein-early endosome interaction . The Journal of Cell Biology . 193 . 7 . 1245–55 . June 2011 . 21708978 . 3216330 . 10.1083/jcb.201011022 .
  19. Yeh TY, Kowalska AK, Scipioni BR, Cheong FK, Zheng M, Derewenda U, Derewenda ZS, Schroer TA . Dynactin helps target Polo-like kinase 1 to kinetochores via its left-handed beta-helical p27 subunit . The EMBO Journal . 32 . 7 . 1023–35 . April 2013 . 23455152 . 3616283 . 10.1038/emboj.2013.30 .
  20. Vaughan KT, Vallee RB . Cytoplasmic dynein binds dynactin through a direct interaction between the intermediate chains and p150Glued . The Journal of Cell Biology . 131 . 6 Pt 1 . 1507–16 . December 1995 . 8522607 . 2120689 . 10.1083/jcb.131.6.1507 .
  21. Morgan JL, Song Y, Barbar E . Structural dynamics and multiregion interactions in dynein-dynactin recognition . The Journal of Biological Chemistry . 286 . 45 . 39349–59 . November 2011 . 21931160 . 3234759 . 10.1074/jbc.M111.296277 . free .
  22. Casper Hoogenraad. Splinter D, Razafsky DS, Schlager MA, Serra-Marques A, Grigoriev I, Demmers J, Keijzer N, Jiang K, Poser I, Hyman AA, Hoogenraad CC, King SJ, Akhmanova A . BICD2, dynactin, and LIS1 cooperate in regulating dynein recruitment to cellular structures . Molecular Biology of the Cell . 23 . 21 . 4226–41 . November 2012 . 22956769 . 3484101 . 10.1091/mbc.E12-03-0210 .
  23. Schlager MA, Hoang HT, Urnavicius L, Bullock SL, Carter AP . In vitro reconstitution of a highly processive recombinant human dynein complex . The EMBO Journal . 33 . 17 . 1855–68 . September 2014 . 24986880 . 4158905 . 10.15252/embj.201488792 .
  24. McKenney RJ, Huynh W, Tanenbaum ME, Bhabha G, Vale RD . Activation of cytoplasmic dynein motility by dynactin-cargo adapter complexes . Science . 345 . 6194 . 337–41 . July 2014 . 25035494 . 4224444 . 10.1126/science.1254198 . 2014Sci...345..337M .
  25. Chowdhury S, Ketcham SA, Schroer TA, Lander GC . Structural organization of the dynein-dynactin complex bound to microtubules . Nature Structural & Molecular Biology . 22 . 4 . 345–7 . April 2015 . 25751425 . 4385409 . 10.1038/nsmb.2996 .
  26. Waterman-Storer CM, Karki SB, Kuznetsov SA, Tabb JS, Weiss DG, Langford GM, Holzbaur EL . The interaction between cytoplasmic dynein and dynactin is required for fast axonal transport . Proceedings of the National Academy of Sciences of the United States of America . 94 . 22 . 12180–5 . October 1997 . 9342383 . 23743 . 10.1073/pnas.94.22.12180 . 1997PNAS...9412180W . free .
  27. McGrail M, Gepner J, Silvanovich A, Ludmann S, Serr M, Hays TS . Regulation of cytoplasmic dynein function in vivo by the Drosophila Glued complex . The Journal of Cell Biology . 131 . 2 . 411–25 . October 1995 . 7593168 . 2199972 . 10.1083/jcb.131.2.411 .
  28. King SJ, Schroer TA . Dynactin increases the processivity of the cytoplasmic dynein motor . Nature Cell Biology . 2 . 1 . 20–4 . January 2000 . 10620802 . 10.1038/71338 . 20349195 .
  29. Berezuk MA, Schroer TA . Dynactin enhances the processivity of kinesin-2 . Traffic . 8 . 2 . 124–9 . February 2007 . 17181772 . 10.1111/j.1600-0854.2006.00517.x . 46446471 .
  30. Echeverri CJ, Paschal BM, Vaughan KT, Vallee RB . Molecular characterization of the 50-kD subunit of dynactin reveals function for the complex in chromosome alignment and spindle organization during mitosis . The Journal of Cell Biology . 132 . 4 . 617–33 . February 1996 . 8647893 . 2199864 . 10.1083/jcb.132.4.617 .
  31. Karki S, Holzbaur EL . Cytoplasmic dynein and dynactin in cell division and intracellular transport . Current Opinion in Cell Biology . 11 . 1 . 45–53 . February 1999 . 10047518 . 10.1016/S0955-0674(99)80006-4 . free .
  32. Gaglio T, Saredi A, Bingham JB, Hasbani MJ, Gill SR, Schroer TA, Compton DA . Opposing motor activities are required for the organization of the mammalian mitotic spindle pole . The Journal of Cell Biology . 135 . 2 . 399–414 . October 1996 . 8896597 . 2121053 . 10.1083/jcb.135.2.399 .
  33. Merdes A, Heald R, Samejima K, Earnshaw WC, Cleveland DW . Formation of spindle poles by dynein/dynactin-dependent transport of NuMA . The Journal of Cell Biology . 149 . 4 . 851–62 . May 2000 . 10811826 . 2174573 . 10.1083/jcb.149.4.851 .
  34. Howell BJ, McEwen BF, Canman JC, Hoffman DB, Farrar EM, Rieder CL, Salmon ED . Cytoplasmic dynein/dynactin drives kinetochore protein transport to the spindle poles and has a role in mitotic spindle checkpoint inactivation . The Journal of Cell Biology . 155 . 7 . 1159–72 . December 2001 . 11756470 . 2199338 . 10.1083/jcb.200105093 .
  35. Starr DA, Williams BC, Hays TS, Goldberg ML . ZW10 helps recruit dynactin and dynein to the kinetochore . The Journal of Cell Biology . 142 . 3 . 763–74 . August 1998 . 9700164 . 2148168 . 10.1083/jcb.142.3.763 .
  36. Whited JL, Cassell A, Brouillette M, Garrity PA . Dynactin is required to maintain nuclear position within postmitotic Drosophila photoreceptor neurons . Development . 131 . 19 . 4677–86 . October 2004 . 15329347 . 2714772 . 10.1242/dev.01366 .
  37. Tsujikawa M, Omori Y, Biyanwila J, Malicki J . Mechanism of positioning the cell nucleus in vertebrate photoreceptors . Proceedings of the National Academy of Sciences of the United States of America . 104 . 37 . 14819–24 . September 2007 . 17785424 . 1976238 . 10.1073/pnas.0700178104 . 2007PNAS..10414819T . free .
  38. Xiang X, Han G, Winkelmann DA, Zuo W, Morris NR . Dynamics of cytoplasmic dynein in living cells and the effect of a mutation in the dynactin complex actin-related protein Arp1 . Current Biology . 10 . 10 . 603–6 . May 2000 . 10837229 . 10.1016/S0960-9822(00)00488-7 . 29254054 . free .
  39. Bruno KS, Tinsley JH, Minke PF, Plamann M . Genetic interactions among cytoplasmic dynein, dynactin, and nuclear distribution mutants of Neurospora crassa . Proceedings of the National Academy of Sciences of the United States of America . 93 . 10 . 4775–80 . May 1996 . 8643479 . 39355 . 10.1073/pnas.93.10.4775 . 1996PNAS...93.4775B . free .
  40. Quintyne NJ, Gill SR, Eckley DM, Crego CL, Compton DA, Schroer TA . Dynactin is required for microtubule anchoring at centrosomes . The Journal of Cell Biology . 147 . 2 . 321–34 . October 1999 . 10525538 . 2174233 . 10.1083/jcb.147.2.321 .
  41. Quintyne NJ, Schroer TA . Distinct cell cycle-dependent roles for dynactin and dynein at centrosomes . The Journal of Cell Biology . 159 . 2 . 245–54 . October 2002 . 12391026 . 2173046 . 10.1083/jcb.200203089 .
  42. Deacon SW, Serpinskaya AS, Vaughan PS, Lopez Fanarraga M, Vernos I, Vaughan KT, Gelfand VI . Dynactin is required for bidirectional organelle transport . The Journal of Cell Biology . 160 . 3 . 297–301 . February 2003 . 12551954 . 2172679 . 10.1083/jcb.200210066 .

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