MCAK associates with the tips of polymerizing microtubules

Moore, Ayana T.; Rankin, Kathleen E.; Dassow, George von; Peris, Leticia; Wagenbach, Michael; Ovechkina, Yulia; Andrieux, Annie; Job, Didier; Wordeman, Linda

doi:10.1083/jcb.200411089

Cited by 131 publications

(169 citation statements)

References 25 publications

(42 reference statements)

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“…This large fragment was precipitated by all of the GST fusion proteins that also precipitated full-length GFP-MCAK (Figures 2c and d, asterisk). We therefore conclude that EB1 associates with the MCAK N-terminus and possibly neck region, a statement supported by previously published work indicating that the ability of GFP-MCAK to tip-track is negatively regulated by phosphorylation of the N-terminal domain (Moore et al, 2005). Notably however, recombinant EB1 proteins appeared to possess a lower affinity for the GFP-MCAK fragment than for full-length GFP-MCAK in the same sample, suggesting that other regions in MCAK might contribute to the association with EB1.…”

supporting

confidence: 66%

“…Plasmids were transfected into COS-7 cells and cultures examined 12 h later by time-lapse fluorescence microscopy. As previously reported (Moore et al, 2005), GFP-MCAK localized to motile comet-like structures in the cytoplasm (Figure 1; Supplementary movie 1, Supplementary Information) whereas GFP-KIF2A did not (not shown). Coimmunostaining of transfected cell cultures revealed colocalization of GFP-MCAK with endogenous EB1 at MT plus ends (Figure 1, panels a and b), consistent with the possibility that MCAK might be associated with EB1 at this site.…”

supporting

confidence: 58%

“…Notably however, recombinant EB1 proteins appeared to possess a lower affinity for the GFP-MCAK fragment than for full-length GFP-MCAK in the same sample, suggesting that other regions in MCAK might contribute to the association with EB1. One possibility is that the MCAK tail, previously shown to contribute to the MT tip-tracking ability of the protein (Moore et al, 2005) contributes to the association with EB1. This is appealing since it suggests that an EB1 association with an inactive form of MCAK where the tail is bound to the neck region (Ems-McClung et al, 2007) might be plausible.…”

mentioning

confidence: 99%

“…If EB1 also associated with MCAK, an interaction between these two functionally opposed proteins could have important implications for the regulation of MT dynamics. Our investigations were given further impetus by a report that MCAK localized to growing MT ends (Moore et al, 2005), since EB1 is known to promiscuously interact with a variety of þ TIPs (Morrison, 2007).…”

mentioning

confidence: 99%

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MCAK associates with EB1

et al. 2007

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The microtubule (MT)-associated protein EB1 localizes to and promotes growth at MT plus ends. The MT depolymerizing kinesin MCAK has also been reported to track growing MT plus ends. Here, we confirm that human MCAK colocalizes with EB1 at growing MT ends when expressed as a GFP fusion protein in transfected cells. We show that MCAK associates with the C-terminus of EB1 and EB3 but much less efficiently with RP1. EB1 associates with the N-terminal localization and regulatory domain in MCAK but not with the motor domain of the protein. The interaction is competitive with the binding of other EB1 ligands and does not require MTs. Knockdown of EB1 expression using siRNA impaired the ability of GFP-MCAK to localize to MT tips in transfected cells. We propose that MCAK is targeted to growing MT ends by EB1, that MCAK is held in an inactive conformation when associated with EB1 and that this could provide the basis for a mechanism that facilitates rapid switching between phases of MT growth and depolymerization.

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supporting

confidence: 66%

supporting

confidence: 58%

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confidence: 99%

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MCAK associates with EB1

et al. 2007

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“…Last, an intriguing finding is that KIF2β, a splice variant of KIF2 that is found in non-neuronal cells and a member of the kinesin-13 family, supposedly drives plus-end-directed transport of lysosomes 95 . This is odd because other members of the kinesin-13 family are non-motile and possess micro tubule-depolymerizing activity 96 . Whether all three classes of kinesins are active on a given organelle, whether their involvement is cell-type specific and whether involvement depends on the state of activity of the cell or organelle in question still remain unclear.…”

Section: Outbound Trafficmentioning

confidence: 99%

Powering membrane traffic in endocytosis and recycling

Soldati

Schliwa

2006

Nat Rev Mol Cell Biol

312

279

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| Early in evolution, the diversification of membrane-bound compartments that characterize eukaryotic cells was accompanied by the elaboration of molecular machineries that mediate intercompartmental communication and deliver materials to specific destinations. Molecular motors that move on tracks of actin filaments or microtubules mediate the movement of organelles and transport between compartments. The subjects of this review are the motors that power the transport steps along the endocytic and recycling pathways, their modes of attachment to cargo and their regulation.The emergence of eukaryotic cells was accompanied by the development of endomembrane systems that compartmentalize biochemical pathways and biosynthetic processes. An evolutionary trend towards increasing complexity and subcellular specialization necessitated the development of machineries for intercompartmental communication. Molecular assemblies evolved to confer specificity to the interactions of donor and acceptor compartments (budding, sorting, tethering and fusion). Cytoskeletal polymers such as actin filaments and microtubules, which help segregate genetic material and determine cell shape and subcellular architecture, were co-opted as tracks for transport. In animal cells, microtubules support long-range transport, whereas the more flexible actin filaments serve short-range movements both near the cell periphery and in the cell interior. Also, actin filaments can be woven into dense networks of short fibres through the action of crosslinkers and branchpromoting complexes. On the other hand, in many plant cells, bundled actin filaments can form extended tracks for long-distance transport. Owing to the gel-like nature of the cytoplasm, the Brownian movement of organelles is severely restricted and cargoes have to be transported to their destinations at the expense of energy. Furthermore, seemingly random, but motor-dependent, movement is proposed to increase the probability of vesicle collisions and therefore promote fusion events. Movement is powered by three ATP-dependent motors: myosin, kinesin and dynein. Over the course of eukaryotic evolution, these motors have diversified into a large number of families with specific tasks (FIG. 1).Here, we review the involvement of molecular motors in the movement of endosomes and in vesicular trafficking along the endocytic and recycling pathways. These pathways are summarized in FIG. 2. We do not, however,

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Microtubules' interaction with cell cortex is required for their radial organization, but not for centrosome positioning

Brodsky¹,

Burakov²,

Nadezhdina³

2007

Cell Motil. Cytoskeleton

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Microtubules in interphase mammalian cells usually form a radial array with minus-ends concentrated in the central region and plus-ends placed at the periphery. This is accepted as correct, that two factors determinate the radial organization of microtubules - the centrosome, which nucleate and anchor the microtubules minus-ends, and the interaction of microtubules with cortical dynein, which positions centrosome in the cell center. However, it looks as if there are additional factors, affecting the radial structure of microtubule system. We show here that in aged Vero cytoplasts (17 h after enucleation) microtubule system lost radial organization and became chaotic. To clear up the reasons of that, we studied centrosome activity, its position in the cytoplasts and microtubule dynamics. We found that centrosome in aged cytoplasts was still active and placed in the central region of the cytoplasm, while after total disruption of the microtubules it was displaced from the center. Microtubules in aged cytoplasts were not stabilized, but they lost their ability to stop to grow near cell cortex and continued to grow reaching it. Aged cytoplast lamellae was partially depleted with dynactin though Golgi remained compact indicating dynein activity. We conclude that microtubule stoppage at cell cortex is mediated by some (protein) factors, and these factors influence radial structure of microtubule system. It seems that the key role in centrosome positioning is played by dynein complexes anchored everywhere in the cytoplasm rather than anchored in cell cortex.

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MCAK associates with the tips of polymerizing microtubules

Cited by 131 publications

References 25 publications

MCAK associates with EB1

MCAK associates with EB1

Powering membrane traffic in endocytosis and recycling

Microtubules' interaction with cell cortex is required for their radial organization, but not for centrosome positioning

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