The Kinesin-Related Protein MCAK Is a Microtubule Depolymerase that Forms an ATP-Hydrolyzing Complex at Microtubule Ends

Hunter, Andrew W.; Caplow, Michael; Coy, David L.; Hancock, William O.; Diez, Stefan; Wordeman, Linda; Howard, Jonathon

doi:10.1016/s1097-2765(03)00049-2

Cited by 349 publications

(406 citation statements)

References 55 publications

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Section: Discussionmentioning

confidence: 99%

“…Nrk30p is more likely to act by accelerating the rate of depolymerization, for example, by phosphorylating a factor that destabilizes the ends of axonemal microtubules. It is tempting to speculate that one of the (direct or indirect) targets of Nrk30p activity is an EB1-like end-stabilizing protein (Pedersen et al, 2003) or an MCAK microtubule end depolymerizer (Hunter et al, 2003;Walczak, 2003).Nrk17p, an NRK related to Fa2p NRK of Chlamydomonas, also caused rapid resorption of cilia. Fa2p is restricted to the transitional region between the BB and the axoneme (Mahjoub et al, 2004), and FA2 mutants are defective in flagellar autotomy, a process that is triggered by microtubule severing in the transitional region (Mahjoub et al, 2002).…”

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confidence: 99%

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Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

Włoga

Camba

Rogowski

et al. 2006

MBoC

103

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The genome of Tetrahymena thermophila contains 39 loci encoding NIMA-related kinases (NRKs), an extraordinarily large number for a unicellular organism. Evolutionary analyses grouped these sequences into several subfamilies, some of which have orthologues in animals, whereas others are protist specific. When overproduced, NRKs of three subfamilies caused rapid shortening of cilia. Ultrastructural studies revealed that each NRK triggered ciliary resorption by a distinct mechanism that involved preferential depolymerization of a subset of axonemal microtubules, at either the distal or proximal end. Overexpression of a kinase-inactive variant caused lengthening of cilia, indicating that constitutive NRK-mediated resorption regulates the length of cilia. Each NRK preferentially resorbed a distinct subset of cilia, depending on the location along the anteroposterior axis. We also show that normal Tetrahymena cells maintain unequal length cilia. We propose that ciliates used a large number of NRK paralogues to differentially regulate the length of specific subsets of cilia in the same cell. INTRODUCTIONHow the size of organelles is determined is an important and largely unanswered question. Cilia have emerged as a model organelle to study the mechanism of size regulation (Marshall, 2002). The size of an organelle is determined by the balance between assembly pathways that deliver structural components and disassembly pathways that remove components. In cilia, the intraflagellar transport (IFT), a bidirectional motility system that operates inside cilia (Rosenbaum and Witman, 2002;Scholey, 2003), plays a key role in length regulation. The anterograde IFT supplies structural subunits during assembly (Piperno et al., 1996;Qin et al., 2005) and maintains the axoneme after assembly (Brown et al., 1999). The retrograde IFT recycles the IFT machinery (Signor et al., 1999) and removes ciliary structural components that turn over (Qin et al., 2004). This turnover is the basis of the disassembly pathway (Stephens, 1997;Marshall and Rosenbaum, 2001;Song and Dentler, 2001;Thazhath et al., 2004). Experimental data and mathematical modeling in Chlamydomonas reinhardtii indicate that the length of flagella is dependent on the rates of elongation (equivalent to the efficiency of anterograde IFT) and disassembly. As the flagellum grows, the rate of elongation decreases due to the limited supply of IFT components that need to travel longer distances to the tip (Marshall and Rosenbaum, 2001). According to the "balance point model," the steady-state length is achieved when the rate of elongation equals the rate of disassembly (Marshall and Rosenbaum, 2001;Marshall et al., 2005).The length of already assembled cilia can be reduced drastically using two mechanisms: autotomy or resorption (reviewed by Quarmby, 2004). During autotomy, the axoneme breaks off from the basal body, the cilium falls off, and the plasma membrane reseals over the basal body. Protists undergo autotomy in response to low pH (Lewin et al., 1982). It is unclear whether...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

Włoga

Camba

Rogowski

et al. 2006

MBoC

103

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“…Of particular interest are members of the kinesin superfamily that regulate the polymerization dynamics of MTs (Wordeman, 2005;Moores and Milligan, 2006;Howard and Hyman, 2007). These include members of the kinesin-13 family (Kif2A, Kif2B, and MCAK/Kif2C), which seem to be strictly MT-depolymerizing enzymes (Desai et al, 1999;Hunter et al, 2003;Helenius et al, 2006), as well as members of the Kinesin-8 family, which are MT plus end-directed motors and plus end-specific depolymerases (Gupta et al, 2006;Howard and Hyman, 2007;Mayr et al, 2007;Varga et al, 2008). MCAK has been shown to be a critical regulator of MT dynamics and organization in vitro, in Xenopus egg extracts and in mammalian cells (Walczak et al, 1996;Desai et al, 1999;Maney et al, 2001;Kline-Smith and Walczak, 2002;Cassimeris and Morabito, 2004;Zhu et al, 2005;Stout et al, 2006;Manning et al, 2007;Ohi et al, 2007;Wordeman et al, 2007;Hedrick et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

MCAK and Paclitaxel Have Differential Effects on Spindle Microtubule Organization and Dynamics

Rizk

Bohannon

Wetzel

et al. 2009

MBoC

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Within the mitotic spindle, there are multiple populations of microtubules with different turnover dynamics, but how these different dynamics are maintained is not fully understood. MCAK is a member of the kinesin-13 family of microtubule-destabilizing enzymes that is required for proper establishment and maintenance of the spindle. Using quantitative immunofluorescence and fluorescence recovery after photobleaching, we compared the differences in spindle organization caused by global suppression of microtubule dynamics, by treating cells with low levels of paclitaxel, versus specific perturbation of spindle microtubule subsets by MCAK inhibition. Paclitaxel treatment caused a disruption in spindle microtubule organization marked by a significant increase in microtubules near the poles and a reduction in K-fiber fluorescence intensity. This was correlated with a faster t 1/2 of both spindle and K-fiber microtubules. In contrast, MCAK inhibition caused a dramatic reorganization of spindle microtubules with a significant increase in astral microtubules and reduction in K-fiber fluorescence intensity, which correlated with a slower t 1/2 of K-fibers but no change in the t 1/2 of spindle microtubules. Our data support the model that MCAK perturbs spindle organization by acting preferentially on a subset of microtubules, and they support the overall hypothesis that microtubule dynamics is differentially regulated in the spindle. INTRODUCTIONThe cytoskeleton must undergo dramatic reorganization as cells transition from interphase to mitosis to assemble the mitotic spindle. The spindle is a macromolecular structure composed of a dynamic array of microtubules (MTs) and their associated proteins that is necessary for proper chromosome segregation (Compton, 2000;Walczak and Heald, 2008). At the onset of mitosis, there is an increase in MT turnover that allows for breakdown of the interphase array and assembly of the mitotic spindle (Saxton et al., 1984;. This change is correlated with an increased catastrophe frequency (transition from growth to shrinkage) and a decreased rescue frequency (transition from shrinkage to growth) (Belmont et al., 1990;Gliksman et al., 1992;Verde et al., 1992;Rusan et al., 2001). The changes in MT dynamics are also correlated with a change in MT polymer levels during mitosis (Zhai et al., 1996). At nuclear envelope breakdown, there is a dramatic decrease in MT polymer levels, which may allow the cell to rapidly assemble a mitotic spindle because the released tubulin dimers can polymerize into new spindle MTs. As the cell progresses from mitosis to the next interphase, there is no change in the levels of MT polymer (Zhai et al., 1996), suggesting that MT polymer gets reorganized to reform the interphase MT cytoskeleton, without a significant change in the dynamics of the MTs. These studies highlight the need for the cell to possess a mechanism to temporally regulate MT dynamics.In addition to the temporal changes in dynamics throughout the cell cycle, the dynamics of MTs within mitosis are also...

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“…Strikingly, MCAK also possesses an ATP-dependent depolymerase activity that acts catalytically and has been proposed to remove tubulin dimers processively from both ends of the microtubule. (29) Molecular motor function A major unanswered question in the motors field is the mechanism by which motors convert energy from ATP hydrolysis into work, enabling the proteins to bind to and move along microtubules or actin filaments. Answering this question will be essential to understand how the motors generate force to transport vesicles and organelles along cytoskeletal fibers and contribute to forces in the spindle during mitosis and meiosis.…”

Section: Introductionmentioning

confidence: 99%

“…(28) By contrast, the KinI motor, MCAK, catalytically depolymerizes microtubules in the presence of ATP, which has been proposed to occur by release of tubulin dimers from microtubule ends. (29) ATP hydrolyzed. (33,34) Thermal fluctuations are expected to play an important role in the motor mechanism, either by driving diffusional movements of the motor to its next binding position (35) or by promoting diffusive structural changes that drive force-producing conformational changes.…”

Section: Introductionmentioning

confidence: 99%

Kinesin motors as molecular machines

Endow

2003

BioEssays

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SummaryMolecular motor proteins, fueled by energy from ATP hydrolysis, move along actin filaments or microtubules, performing work in the cell. The kinesin microtubule motors transport vesicles or organelles, assemble bipolar spindles or depolymerize microtubules, functioning in basic cellular processes. The mechanism by which motor proteins convert energy from ATP hydrolysis into work is likely to differ in basic ways from man-made machines. Several mechanical elements of the kinesin motors have now been tentatively identified, permitting researchers to begin to decipher the mechanism of motor function. The force-producing conformational changes of the motor and the means by which they are amplified are probably different for the plus-and minus-end kinesin motors.

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The Kinesin-Related Protein MCAK Is a Microtubule Depolymerase that Forms an ATP-Hydrolyzing Complex at Microtubule Ends

Cited by 349 publications

References 55 publications

Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

MCAK and Paclitaxel Have Differential Effects on Spindle Microtubule Organization and Dynamics

Kinesin motors as molecular machines

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