Revolving movement of a dynamic cluster of actin filaments during mitosis

Mitsushima, Masaru; Aoki, Kazuhiro; Ebisuya, Miki; Matsumura, Shigeki; Yamamoto, Takuya; Matsuda, Minoru; Toyoshima, Fumiko; Nishida, Eisuke

doi:10.1083/jcb.201007136

Cited by 71 publications

(88 citation statements)

References 34 publications

(36 reference statements)

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“…The basis for these changes is not known, but we showed that inhibition of Cdk1 activity reduced cable-assembly rates and cable intensity in vivo. Recent reports in metazoans revealed up-regulation of actin assembly during metaphase (42,43,45). However, which types of actin filament networks are being regulated and which actin nucleation systems are being regulated are unclear.…”

Section: Understanding How Actin Cables Of Defined Architecture and Pmentioning

confidence: 99%

“…Recently, F-actin assembly was found to be regulated by the cell cycle in vertebrates (43,45). Actin bundles assembled in metaphase were thicker and/or more prevalent than those assembled in interphase (43).…”

Section: Reconstitution Of Bni1-derived Actin Cable Assembly In Mitotmentioning

confidence: 99%

“…However, which types of actin filament networks are being regulated and which actin nucleation systems are being regulated are unclear. The Arp2/3 complex was suggested to be responsible for such metaphase-specific events for cell division (43,45,98). On the other hand, the formin protein Fmn2 was suggested to cooperate with Spire to assemble metaphase actin filaments for asymmetric cell divisions (99)(100)(101).…”

Section: Understanding How Actin Cables Of Defined Architecture and Pmentioning

confidence: 99%

“…Interestingly, several recent reports provided evidence for cell-cycle regulation of F-actin dynamics in oocytes and early embryos (42)(43)(44)(45). However, which specific types of actin structures are regulated by the cell cycle and what kind of nucleation factors and actin interacting-proteins are involved remain to be determined.…”

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confidence: 99%

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Cell-cycle regulation of formin-mediated actin cable assembly

Miao

Wong

Mennella

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Assembly of appropriately oriented actin cables nucleated by formin proteins is necessary for many biological processes in diverse eukaryotes. However, compared with knowledge of how nucleation of dendritic actin filament arrays by the actin-related protein-2/3 complex is regulated, the in vivo regulatory mechanisms for actin cable formation are less clear. To gain insights into mechanisms for regulating actin cable assembly, we reconstituted the assembly process in vitro by introducing microspheres functionalized with the C terminus of the budding yeast formin Bni1 into extracts prepared from yeast cells at different cell-cycle stages. EM studies showed that unbranched actin filament bundles were reconstituted successfully in the yeast extracts. Only extracts enriched in the mitotic cyclin Clb2 were competent for actin cable assembly, and cyclin-dependent kinase 1 activity was indispensible. Cyclin-dependent kinase 1 activity also was found to regulate cable assembly in vivo. Here we present evidence that formin cellcycle regulation is conserved in vertebrates. The use of the cablereconstitution system to test roles for the key actin-binding proteins tropomyosin, capping protein, and cofilin provided important insights into assembly regulation. Furthermore, using mass spectrometry, we identified components of the actin cables formed in yeast extracts, providing the basis for comprehensive understanding of cable assembly and regulation.Cdk1 | three-dimensional structured-illumination microscopy | actin nucleation E ukaryotic cells contain populations of actin structures with distinct architectures and protein compositions, which mediate varied cellular processes (1). Understanding how F-actin polymerization is regulated in time and space is critical to understanding how actin structures provide mechanical forces for corresponding biological processes. Branched actin filament arrays, which concentrate at sites of clathrin-mediated endocytosis (2, 3) and at the leading edge of motile cells (4), are nucleated by the actin-related protein-2/3 (Arp2/3) complex. In contrast, bundles of unbranched actin filaments, which sometimes mediate vesicle trafficking or form myosin-containing contractile bundles, often are nucleated by formin proteins (5-14).Much has been learned about how branched actin filaments are polymerized by the Arp2/3 complex and how these filaments function in processes such as endocytosis (2, 15). In contrast, relatively little is known about how actin cables are assembled under physiological conditions. In previous studies, branched actin filaments derived from the Arp2/3 complex have been reconstituted using purified proteins (16)(17)(18)(19) or cellular extracts (20-25). When microbeads were coated with nucleation-promoting factors for the Arp2/3 complex and then were incubated in cell extracts, actin comet tails were formed by sequential actin nucleation, symmetry breaking, and tail elongation. Importantly, the motility behavior of F-actin assembled by the Arp2/3 complex using defined, purified pr...

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Section: Understanding How Actin Cables Of Defined Architecture and Pmentioning

confidence: 99%

Section: Reconstitution Of Bni1-derived Actin Cable Assembly In Mitotmentioning

confidence: 99%

Section: Understanding How Actin Cables Of Defined Architecture and Pmentioning

confidence: 99%

mentioning

confidence: 99%

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Cell-cycle regulation of formin-mediated actin cable assembly

Miao

Wong

Mennella

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…In fact, the spindle F‐actin has been shown to surround mitotic spindles during early Xenopus embryo mitosis 22. Arp2/3 protein complex, which is involved in the nucleation and assembly of branched actin filaments, has been shown to participate in the formation of the spindle F‐actin 52, 53. In summary, we demonstrate that ADD1 phosphorylation at S726 is important for its interaction with TPX2 and for spindle pole integrity.…”

Section: Discussionmentioning

confidence: 64%

Adducin‐1 is essential for spindle pole integrity through its interaction with TPX2

et al. 2018

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Bipolar spindle assembly is necessary to ensure the proper progression of cell division. Loss of spindle pole integrity leads to multipolar spindles and aberrant chromosomal segregation. However, the mechanism underlying the maintenance of spindle pole integrity remains unclear. In this study, we show that the actin‐binding protein adducin‐1 (ADD1) is phosphorylated at S726 during mitosis. S726‐phosphorylated ADD1 localizes to centrosomes, wherein it organizes into a rosette‐like structure at the pericentriolar material. ADD1 depletion causes centriole splitting and therefore results in multipolar spindles during mitosis, which can be restored by re‐expression of ADD1 and the phosphomimetic S726D mutant but not by the S726A mutant. Moreover, the phosphorylation of ADD1 at S726 is crucial for its interaction with TPX2, which is essential for spindle pole integrity. Together, our findings unveil a novel function of ADD1 in maintaining spindle pole integrity through its interaction with TPX2.

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