Visualization of the stop of microtubule depolymerization that occurs at the high-density region of microtubule-associated protein 2 (MAP2)

Ichihara, Koji; Kitazawa, Hidefumi; Iguchi, Yusuke; Hotani, Hirokazu; Itoh, Tomohiko J.

doi:10.1006/jmbi.2001.4934

Cited by 20 publications

(24 citation statements)

References 51 publications

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“…The regulators of MT dynamics are important for control of chromosome movement and mitosis (Gigant et al, 2000;Howell et al, 2001;Ichihara et al, 2001). As for these regulators in cancer cells, the catastrophe factors of MTs such as oncoprotein (Op)18/ stathmin were reported to be overexpressed in a number of human malignancies, and to be associated with cancer progression and prognosis (Roos et al, 1993;Bieche et al, 1998a, b;Brattsand, 2000;Chen et al, 2003;Moore and Wordeman, 2004;Kouzu et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Clinicopathological and biological significance of mitotic centromere-associated kinesin overexpression in human gastric cancer

et al. 2007

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Mitotic centromere-associated kinesin (MCAK) is a microtubule (MT) depolymerase necessary for ensuring proper kinetochore MT attachment during spindle formation. To determine MCAK expression status and its clinicopathological significance, real-time reverse transcriptase -polymerase chain reaction was used in 65 cases of gastric cancer. MCAK gene expression in cancer tissue was significantly higher than expression in non-malignant tissue (Po0.05). Elevated MCAK expression was significantly associated with lymphatic invasion (P ¼ 0.01) and lymph node metastasis (P ¼ 0.04). Furthermore, patients with high MCAK expression had a significantly poorer survival rate than those with low MCAK expression (P ¼ 0.008). Immunohistochemical study revealed that expression of MCAK was primarily observed in cancer cells. Additionally, a gastric cancer cell line (AZ521) that stably expressed MCAK was established and used to investigate the biological effects of the MCAK gene. In vitro results showed that cells transfected with MCAK had a high rate of proliferation (Po0.001) and increased migratory ability (Po0.001) compared to mock-transfected cells. This study demonstrated that elevated expression of MCAK may be associated with lymphatic invasion, lymph node metastasis, and poor prognosis. These characteristics may be due in part to the increased proliferative and migratory ability of cells expressing MCAK.

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Section: Discussionmentioning

confidence: 99%

Clinicopathological and biological significance of mitotic centromere-associated kinesin overexpression in human gastric cancer

et al. 2007

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“…Optical Microscopic Observation of MT Dynamics-To determine the exact effects of RB3s on MT dynamics, individual MTs were monitored using a dark field microscope with several modifications (27)(28)(29). First, 24 M of tubulin was added to allow the polymerization of MTs in PM buffer containing 1 mM GTP at 37°C for 5 min.…”

Section: Methodsmentioning

confidence: 99%

Modulation of the Stathmin-like Microtubule Destabilizing Activity of RB3, a Neuron-specific Member of the SCG10 Family, by Its N-terminal Domain

Nakao

Itoh

Hotani

et al. 2004

Journal of Biological Chemistry

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RB3 is a neuron-specific homologue of the SCG10/ stathmin family proteins, possessing a unique N-terminal membrane-associated domain and the stathmin-like domain at the C terminus, which promotes microtubule (MT) catastrophe and/or tubulin sequestering. We examined herein the contribution of the N-terminal subdomain of RB3 to the regulation of MT dynamics. To begin with, we determined the effects of full-length (RB3-f) and short truncated (RB3-s) forms of RB3 on the polymerization of MT in vitro. RB3-s had a deletion of amino acids 1-75 from the N terminus, leaving the so-called stathmin-like domain, consisting of residues 76 -217. Although both RB3-f and RB3-s exhibited MT-depolymerizing activity, RB3-f was less effective. The binding affinity for tubulin was also lower in RB3-f. Direct observation of the dynamics of individual MTs using dark field microscopy revealed that RB3-s slowed MT elongation velocity, increased catastrophes, and reduced rescues. This effect is almost identical to that by stathmin/oncoprotein 18. On the other hand, the MT elongation rate increased at lower concentrations of RB3-f. In addition, RB3-f, indicated higher rescue frequency than control as well as the catastrophe in a dosedependent manner. The functionality of RB3-f indicated that full-length RB3 has not only stathmin-like MT destabilizing activity but also MT-associated protein-like MT stabilizing activity. Possibly, the balance of these activities is altered in a concentration-dependent manner in vitro. This interesting regulatory role of the unique N-terminal domain of RB3 in MT dynamics would contribute to the physiological regulation of neuronal morphogenesis.

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“…5). This indicates that high-density regions, which are required to stop depolymerization (Ichihara et al, 2001), are more difficult to form in PJ2 than in MAP4 at lower concentrations. This supports the hypothesis that the cooperativity of binding is higher in PJ2 than in MAP4.…”

Section: Discussionmentioning

confidence: 99%

“…Lowering the association rate would increase the probability of loss of GTP-cap resulting in the high frequency of catastrophe. Rescue events also depend on the amount of bound MAPs, because they occur at the high-density region of MAP2 along the MT lattice (Ichihara et al, 2001). However, the presence of exceptionally longer depolymerization phases is difficult to explain only by an increased amount of bound MAP.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, MAP4, a ubiquitous heat-stable MAP (Bulinski, 1994), strongly enhanced the rescue frequency without decreasing the catastrophe frequency (Ookata et al, 1995). Presumably, the mode of the binding of heat-stable MAP along MT lattice is important at least for the rescue, since it was demonstrated that MAP2 bound inhomogeneously onto MT surface, and that rescue occurred only at the sites where MAP2 density was high (Ichihara et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Truncation of the Projection Domain of MAP4 (Microtubule-Associated Protein 4) Leads to Attenuation of Microtubule Dynamic Instability

Permana

Hisanaga

Nagatomo

et al. 2005

Cell Struct. Funct.

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ABSTRACT. MAP4, a ubiquitous heat-stable MAP, is composed of an asymmetric structure common to the heatstable MAPs, consisting of an N-terminal projection (PJ) domain and a C-terminal microtubule (MT)-binding (MTB) domain. Although the MTB domain has been intensively studied, the role of the PJ domain, which protrudes from MT-wall and does not bind to MTs, remains unclear. We investigated the roles of the PJ domain on the dynamic instability of MTs by dark-field microscopy using various PJ domain deletion constructs of human MAP4 (PJ1, PJ2, Na-MTB and KDM-MTB). There was no obvious difference in the dynamic instability between the wtMAP4 and any fragments at 0.1 mM, the minimum concentration required to stabilize MTs. The individual MTs stochastically altered between polymerization and depolymerization phases with similar profiles of length change as had been observed in the presence of MAP2 or tau. We also examined the effects at the increased concentrations of 0.7 mM, and found that in some cases the dynamic instability was almost entirely attenuated. The length of both the polymerization and depolymerization phases decreased and "pause-phases" were occasionally observed, especially in the case of PJ1, PJ2 or Na-MTB. No obvious change was observed in the increased concentration of wtMAP4 and KDM-MTB. Additionally, the profiles of MT length change were quite different in 0.7 mM PJ2. Relatively rapid and long depolymerization phases were sometimes observed among quite slow length changes. Perhaps, this unusual profile could be due to the uneven distribution of PJ2 along the MT lattice. These results indicate that the PJ domain of MAP4 participates in the regulation of the dynamic instability.

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Visualization of the stop of microtubule depolymerization that occurs at the high-density region of microtubule-associated protein 2 (MAP2)

Cited by 20 publications

References 51 publications

Clinicopathological and biological significance of mitotic centromere-associated kinesin overexpression in human gastric cancer

Clinicopathological and biological significance of mitotic centromere-associated kinesin overexpression in human gastric cancer

Modulation of the Stathmin-like Microtubule Destabilizing Activity of RB3, a Neuron-specific Member of the SCG10 Family, by Its N-terminal Domain

Truncation of the Projection Domain of MAP4 (Microtubule-Associated Protein 4) Leads to Attenuation of Microtubule Dynamic Instability

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