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Swinging a sword: how microtubules search for their targets.

Pavin N, Tolić-Nørrelykke IM - Syst Synth Biol (2014)

Bottom Line: The cell interior is in constant movement, which is to a large extent determined by microtubules, thin and long filaments that permeate the cytoplasm.To move large objects, microtubules need to connect them to the site of their destination.For example, during cell division, microtubules connect chromosomes with the spindle poles via kinetochores, protein complexes on the chromosomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, 10000 Zagreb, Croatia.

ABSTRACT
The cell interior is in constant movement, which is to a large extent determined by microtubules, thin and long filaments that permeate the cytoplasm. To move large objects, microtubules need to connect them to the site of their destination. For example, during cell division, microtubules connect chromosomes with the spindle poles via kinetochores, protein complexes on the chromosomes. A general question is how microtubules, while being bound to one structure, find the target that needs to be connected to this structure. Here we review the mechanisms of how microtubules search for kinetochores, with emphasis on the recently discovered microtubule feature to explore space by pivoting around the spindle pole. In addition to accelerating the search for kinetochores, pivoting helps the microtubules to search for cortical anchors, as well as to self-organize into parallel arrays and asters to target specific regions of the cell. Thus, microtubule pivoting constitutes a mechanism by which they locate targets in different cellular contexts.

No MeSH data available.


Related in: MedlinePlus

Models of kinetochore capture. a Search-and-capture; b bias in microtubule dynamics towards the chromosomes; c nucleation of microtubules at the chromosomes; d nucleation of microtubules at the kinetochores; e nucleation of microtubules at spindle microtubules; f pivoting of microtubules around the spindle pole; g pivoting of kinetochore-bound microtubules; h kinetochore movements. Microtubules are depicted as green lines, kinetochores as pink spheres on the chromosomes (gray), and centrosomes as gray spheres. Ran-GTP is represented by a pinkgradient in (b), and augmin complexes by small blue spheres in (e). Dashed lines mark microtubule growth (a–e), microtubule pivoting (f, g) and the movement of the chromosome (h). In each panel, structures of interest are intensely colored, whereas the remaining parts of the spindle are pale. (Color figure online)
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Fig1: Models of kinetochore capture. a Search-and-capture; b bias in microtubule dynamics towards the chromosomes; c nucleation of microtubules at the chromosomes; d nucleation of microtubules at the kinetochores; e nucleation of microtubules at spindle microtubules; f pivoting of microtubules around the spindle pole; g pivoting of kinetochore-bound microtubules; h kinetochore movements. Microtubules are depicted as green lines, kinetochores as pink spheres on the chromosomes (gray), and centrosomes as gray spheres. Ran-GTP is represented by a pinkgradient in (b), and augmin complexes by small blue spheres in (e). Dashed lines mark microtubule growth (a–e), microtubule pivoting (f, g) and the movement of the chromosome (h). In each panel, structures of interest are intensely colored, whereas the remaining parts of the spindle are pale. (Color figure online)

Mentions: The pioneering idea termed “search-and-capture” relies on the dynamics of microtubules and their nucleation at centrosomes (Kirschner and Mitchison 1986). As a microtubule grows from the centrosome in an arbitrary direction, it probes the space as it searches for kinetochores. Even though a single microtubule probes only one direction, numerous directions will be explored eventually because numerous microtubules grow from the centrosome (Fig. 1a).Fig. 1


Swinging a sword: how microtubules search for their targets.

Pavin N, Tolić-Nørrelykke IM - Syst Synth Biol (2014)

Models of kinetochore capture. a Search-and-capture; b bias in microtubule dynamics towards the chromosomes; c nucleation of microtubules at the chromosomes; d nucleation of microtubules at the kinetochores; e nucleation of microtubules at spindle microtubules; f pivoting of microtubules around the spindle pole; g pivoting of kinetochore-bound microtubules; h kinetochore movements. Microtubules are depicted as green lines, kinetochores as pink spheres on the chromosomes (gray), and centrosomes as gray spheres. Ran-GTP is represented by a pinkgradient in (b), and augmin complexes by small blue spheres in (e). Dashed lines mark microtubule growth (a–e), microtubule pivoting (f, g) and the movement of the chromosome (h). In each panel, structures of interest are intensely colored, whereas the remaining parts of the spindle are pale. (Color figure online)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4127178&req=5

Fig1: Models of kinetochore capture. a Search-and-capture; b bias in microtubule dynamics towards the chromosomes; c nucleation of microtubules at the chromosomes; d nucleation of microtubules at the kinetochores; e nucleation of microtubules at spindle microtubules; f pivoting of microtubules around the spindle pole; g pivoting of kinetochore-bound microtubules; h kinetochore movements. Microtubules are depicted as green lines, kinetochores as pink spheres on the chromosomes (gray), and centrosomes as gray spheres. Ran-GTP is represented by a pinkgradient in (b), and augmin complexes by small blue spheres in (e). Dashed lines mark microtubule growth (a–e), microtubule pivoting (f, g) and the movement of the chromosome (h). In each panel, structures of interest are intensely colored, whereas the remaining parts of the spindle are pale. (Color figure online)
Mentions: The pioneering idea termed “search-and-capture” relies on the dynamics of microtubules and their nucleation at centrosomes (Kirschner and Mitchison 1986). As a microtubule grows from the centrosome in an arbitrary direction, it probes the space as it searches for kinetochores. Even though a single microtubule probes only one direction, numerous directions will be explored eventually because numerous microtubules grow from the centrosome (Fig. 1a).Fig. 1

Bottom Line: The cell interior is in constant movement, which is to a large extent determined by microtubules, thin and long filaments that permeate the cytoplasm.To move large objects, microtubules need to connect them to the site of their destination.For example, during cell division, microtubules connect chromosomes with the spindle poles via kinetochores, protein complexes on the chromosomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, 10000 Zagreb, Croatia.

ABSTRACT
The cell interior is in constant movement, which is to a large extent determined by microtubules, thin and long filaments that permeate the cytoplasm. To move large objects, microtubules need to connect them to the site of their destination. For example, during cell division, microtubules connect chromosomes with the spindle poles via kinetochores, protein complexes on the chromosomes. A general question is how microtubules, while being bound to one structure, find the target that needs to be connected to this structure. Here we review the mechanisms of how microtubules search for kinetochores, with emphasis on the recently discovered microtubule feature to explore space by pivoting around the spindle pole. In addition to accelerating the search for kinetochores, pivoting helps the microtubules to search for cortical anchors, as well as to self-organize into parallel arrays and asters to target specific regions of the cell. Thus, microtubule pivoting constitutes a mechanism by which they locate targets in different cellular contexts.

No MeSH data available.


Related in: MedlinePlus