The Motility of Axonemal Dynein Is Regulated by the Tubulin Code

Alper, Joshua; Decker, Franziska; Agana, Bernice A.; Howard, Jonathon

doi:10.1016/j.bpj.2014.10.061

Cited by 69 publications

(46 citation statements)

References 49 publications

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“…Similar findings have been reported in vivo, where the Dynactin subunit p150 and tubulin tyrosination were shown to mediate the initiation of retrograde vesicle transport in neurons [359]. Finally, these data are in line with previous studies reporting that p150/Dynactin has higher affinity for tyrosinated microtubules [325,360] and that the motility of both cytoplasmic and axonemal Dyneins highly depends on tubulin C-terminal tails [325,361,362,363]. …”

Section: Mechanisms Of Chromosome Congressionsupporting

confidence: 89%

Mechanisms of Chromosome Congression during Mitosis

Maiato

Gomes

Sousa

et al. 2017

Biology

159

176

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Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E) that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle microtubule diversity by means of tubulin post-translational modifications. This so-called “tubulin code” might work as a navigation system that selectively guides kinetochore motors with opposite polarities along specific spindle microtubule populations, ultimately leading to the congression of peripheral chromosomes. We propose an integrated model of chromosome congression in mammalian cells that depends essentially on the following parameters: (1) chromosome position relative to the spindle poles after nuclear envelope breakdown; (2) establishment of stable end-on kinetochore-microtubule attachments and bi-orientation; (3) coordination between kinetochore- and arm-associated motors; and (4) spatial signatures associated with post-translational modifications of specific spindle microtubule populations. The physiological consequences of abnormal chromosome congression, as well as the therapeutic potential of inhibiting chromosome congression are also discussed.

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Section: Mechanisms Of Chromosome Congressionsupporting

confidence: 89%

Mechanisms of Chromosome Congression during Mitosis

Maiato

Gomes

Sousa

et al. 2017

Biology

159

176

View full text Add to dashboard Cite

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“…28,29 The lack of glutamylation in the purified T. thermophila tubulin was surprising, given that it was a prominent tubulin PTM in Tetrahymena cells 30 and was not excluded by a TOG purification of Chlamydomonas tubulin. 31 Our relatively homogeneous population of glycylated tubulin allowed us to quantify how the conformational ensemble was affected by the presence of glycylation.…”

Section: Resultsmentioning

confidence: 99%

Molecular Determinants of Tubulin’s C-Terminal Tail Conformational Ensemble

et al. 2016

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Tubulin is important for a wide variety of cellular processes including cell division, ciliogenesis, and intracellular trafficking. To perform these diverse functions, tubulin is regulated by post-translational modifications (PTM), primarily at the C-terminal tails of both the α- and β-tubulin heterodimer subunits. The tubulin C-terminal tails are disordered segments that are predicted to extend from the ordered tubulin body and may regulate both intrinsic properties of microtubules and the binding of microtubule associated proteins (MAP). It is not understood how either interactions with the ordered tubulin body or PTM affect tubulin’s C-terminal tails. To probe these questions, we developed a method to isotopically label tubulin for C-terminal tail structural studies by NMR. The conformational changes of the tubulin tails as a result of both proximity to the ordered tubulin body and modification by mono- and polyglycine PTM were determined. The C-terminal tails of the tubulin dimer are fully disordered and, in contrast with prior simulation predictions, exhibit a propensity for β-sheet conformations. The C-terminal tails display significant chemical shift differences as compared to isolated peptides of the same sequence, indicating that the tubulin C-terminal tails interact with the ordered tubulin body. Although mono- and polyglycylation affect the chemical shift of adjacent residues, the conformation of the C-terminal tail appears insensitive to the length of polyglycine chains. Our studies provide important insights into how the essential disordered domains of tubulin function.

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“…Recent studies revealed that ciliary motility is regulated by the B-microtubule modification polyglutamylation (Alper et al 2014; Ikegami et al 2010; Kubo et al 2010; Suryavanshi et al 2010) see also (Sirajuddin et al 2014). Kubo et al, (2012) proposed that dynein e and/or the N-DRC might be regulated by B-tubule polyglutamylation.…”

Section: Resultsmentioning

confidence: 99%

The nexin link and B‐tubule glutamylation maintain the alignment of outer doublets in the ciliary axoneme

Alford

Stoddard

et al. 2016

Cytoskeleton

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We developed quantitative assays to test the hypothesis that the N-DRC is required for integrity of the ciliary axoneme. We examined reactivated motility of demembranated drc cells, commonly termed “reactivated cell models.” ATP-induced reactivation of wild-type cells resulted in the forward swimming of ~90% of cell models. ATP-induced reactivation failed in a subset of drc cell models, despite forward motility in live drc cells. Dark-field light microscopic observations of drc cell models revealed various degrees of axonemal splaying. In contrast, >98% of axonemes from wild-type reactivated cell models remained intact. The sup-pf4 and drc3 mutants, unlike other drc mutants, retain most of the N-DRC linker that interconnects outer doublet microtubules. Reactivated sup-pf4 and drc3 cell models displayed nearly wild-type levels of forward motility. Thus, the N-DRC linker is required for axonemal integrity. We also examined reactivated motility and axoneme integrity in mutants defective in tubulin polyglutamylation. ATP-induced reactivation resulted in forward swimming of >75% of tpg cell models. Analysis of double mutants defective in tubulin polyglutamylation and different regions of the N-DRC indicate B-tubule polyglutamylation and the distal lobe of the linker region are both important for axonemal integrity and normal N-DRC function.

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The Motility of Axonemal Dynein Is Regulated by the Tubulin Code

Cited by 69 publications

References 49 publications

Mechanisms of Chromosome Congression during Mitosis

Mechanisms of Chromosome Congression during Mitosis

Molecular Determinants of Tubulin’s C-Terminal Tail Conformational Ensemble

The nexin link and B‐tubule glutamylation maintain the alignment of outer doublets in the ciliary axoneme

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