Structure of the tubulin dimer in zinc-induced sheets

Baker, Timothy S.; Amos, Linda

doi:10.1016/0022-2836(78)90378-9

Cited by 99 publications

(50 citation statements)

References 32 publications

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“…Although zinc sheets used for electron crystallography have a protofilament structure similar to MTs, they differ significantly from MTs in their superstructure. (4) Unlike MTs, zinc sheets are not polar-their protofilaments are antiparallel. In addition, when viewing a surface of the zinc sheet, the protofilaments alternate between having ''outside'' versus ''inside'' faces exposed (''outside'' and ''inside'' refer to the surfaces of the protofilament on the outside and inside of the MT, respectively).…”

Section: Structural Features Of the ␣␤ Tubulin Dimer And Ftszmentioning

confidence: 98%

“…The electron crystallography was performed on nonphysiological tubulin sheets polymerized in the presence of zinc ions that have a similar protofilament structure to MTs and, being large, flat, and highly ordered, are ideal for electron diffraction studies. The ability of tubulin to form zinc sheets and the value of these sheets for structural analysis was recognized a while ago, (3)(4)(5) but technical innovations by Nogales et al in the preservation and embedding of these sheets, (6) combined with the use of low-dose cryoelectron microscopy, were central in extending earlier lowresolution studies (7)(8)(9) to an atomic level.In an accompanying paper, Lö we and Amos (2) present the structure of FtsZ, a cell division protein conserved in Eubacteria, Archaebacteria, Mycoplasmas, and chloroplasts that localizes to a constricting ring structure at the division site. (10) …”

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Tubulin and FtsZ structures: functional and therapeutic implications

Desai

Mitchison

1998

Bioessays

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Section: Structural Features Of the ␣␤ Tubulin Dimer And Ftszmentioning

confidence: 98%

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confidence: 98%

Tubulin and FtsZ structures: functional and therapeutic implications

Desai

Mitchison

1998

Bioessays

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“…Sheets of protofilaments in an antiparallel arrangement with opposite surfaces exposed (inside out versus outside in) are produced (40,41) (Fig. 4A).…”

Section: Binding Of Full-length Togp Tomentioning

confidence: 99%

The Interaction of TOGp with Microtubules and Tubulin

Spittle¹,

Charrasse²,

Larroque³

et al. 2000

Journal of Biological Chemistry

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TOGp is the human homolog of XMAP215, a Xenopus microtubule-associated protein that promotes rapid microtubule assembly at plus ends. These proteins are thought to be critical for microtubule assembly and/or mitotic spindle formation. To understand how TOGp interacts with the microtubule lattice, we cloned fulllength TOGp and various truncations for expression in a reticulocyte lysate system. Based on microtubule co-pelleting assays, the microtubule binding domain is contained within a basic 600-amino acid region near the N terminus, with critical domains flanking a region homologous to the microtubule binding domain found in the related proteins Stu2p (S. cerevisiae) and Dis1 (S. pombe). Both full-length TOGp and the N-terminal fragment show enhanced binding to microtubule ends. Full-length TOGp also binds altered polymer lattice structures including parallel protofilament sheets, antiparallel protofilament sheets induced with zinc ions, and protofilament rings, suggesting that TOGp binds along the length of individual protofilaments. The Cterminal region of TOGp has a low affinity for microtubule polymer but binds tubulin dimer. We propose a model to explain the microtubule-stabilizing and/or assembly-promoting functions of the XMAP215/TOGp family of microtubule-associated proteins based on the binding properties we have identified.Microtubule assembly is regulated in cells to generate a relatively stable interphase microtubule array or the much more dynamic microtubules of the mitotic spindle. In either cell cycle stage, the major pathway of microtubule turnover is dynamic instability, where microtubules exist in persistent phases of growth or shortening with the abrupt transitions, termed catastrophe and rescue, between these phases (1). Several classes of microtubule assembly regulators have been identified that can be broadly classified as microtubule stabilizers (e.g. tau, MAP2, 1 or MAP4) or destabilizers (e.g. XKCM1 or oncoprotein 18; reviewed in Refs. 2 and 3). Together, the activities of these accessory proteins generate the dynamic microtubules observed in vivo (reviewed in Refs. 3 and 4).The stabilizing MAP, XMAP215, was initially isolated based on its preferential promotion of microtubule plus end assembly rates (5). Remarkably, this protein speeds the microtubule plus end growth rate by 7-10-fold, primarily through an increase in the apparent on-rate constant (5, 6). In contrast, other stabilizing MAPs, such as tau or MAP2, modestly increase growth rates ϳ2-fold at both microtubule ends, primarily through a decrease in the off-rate constant (7-9). More recent studies have demonstrated that the plus end stabilizing activity of XMAP215 can also counterbalance the catastrophe-promoting activity of XKCM1 (10). The mechanisms responsible for assembly promotion and catastrophe protection by XMAP215 are not known.Given the potent and unique effects of XMAP215 on microtubule assembly in vitro and in Xenopus egg extracts (5, 6, 10, 11), it is not surprising that a number of homologs have been identified in...

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“…FtsZ can form several types of lateral bonds when exogenous cations are added, resulting in a variety of paired protofilaments, bundles, double layered sheets, and tubes (6 -8, 10, 16). For tubulin, aberrant lateral bonds can result in the formation of zinc sheets (17) and hooked and S-shaped polymers (18). It is unclear for FtsZ whether any of the lateral contacts that form in vitro are relevant in vivo.…”

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Polymerization of FtsZ, a Bacterial Homolog of Tubulin

Romberg

Simon

Erickson

2001

Journal of Biological Chemistry

198

257

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FtsZ is a bacterial homolog of tubulin that is essential for prokaryotic cytokinesis. In vitro, GTP induces FtsZ to assemble into straight, 5-nm-wide polymers. Here we show that the polymerization of these FtsZ filaments most closely resembles noncooperative (or "isodesmic") assembly; the polymers are single-stranded and assemble with no evidence of a nucleation phase and without a critical concentration. We have developed a model for the isodesmic polymerization that includes GTP hydrolysis in the scheme. The model can account for the lengths of the FtsZ polymers and their maximum steady state nucleotide hydrolysis rates. It predicts that unlike microtubules, FtsZ protofilaments consist of GTP-bound FtsZ subunits that hydrolyze their nucleotide only slowly and are connected by high affinity longitudinal bonds with a nanomolar K D .

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Structure of the tubulin dimer in zinc-induced sheets

Cited by 99 publications

References 32 publications

Tubulin and FtsZ structures: functional and therapeutic implications

Tubulin and FtsZ structures: functional and therapeutic implications

The Interaction of TOGp with Microtubules and Tubulin

Polymerization of FtsZ, a Bacterial Homolog of Tubulin

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