Cytokinesis Cytoskeleton

Role of the Cytoskeleton in Cell Division Formation of the Mitotic Spindle, Mitosis, and Cytokinesis Drug Effects on Microtubules Mlcrofllaments Actin Filaments Structure and Composition... 

Fig. 2.3 The development of polarity and asymmetric division in Saccharomyces cerevisiae. The diagram is reproduced in a slightly simplified form from the work of Lew Reed (1995) with the permission of Current Opinion in Genetics and Development, (a) The F-actin cytoskeleton strands = actin cables ( ) cortical actin patches, (b) The polarity of growth is indicated by the direction of the arrows (arrows in many directions signifies isotropic growth), (c) 10-nm filaments which are assembled to form a ring at the neck between mother and bud. (d) Construction of the cap at the pre-bud site. Notice that the proteins of the cap become dispersed at the apical/isotropic switch, first over the whole surface of the bud, then more widely. Finally, secretion becomes refocussed at the neck in time for cytokinesis, (e) The status and distribution of the nucleus and microtubules of the spindle. Notice how the spindle pole body ( ) plays an important part in orientation of the mitotic spindle.

Valster, A.H., Pierson, E.S., Valenta, R. et al. 1997. Probing the plant actin cytoskeleton during cytokinesis and interphase by profilin microinjection. Plant Cell 9 1815-1824. 

Valster, A. H. and Hepler, P. K. 1997. Caffeine inhibition of cytokinesis effect on the phragmoplast cytoskeleton in living Tradescantia stamen hair cells. Protoplasma 196, 155-166... 

The cytoskeletal network is responsible for the mechanical properties of the cell that modulate functions such as cell shape, locomotion, cytokinesis, and translocation of organelles. Experimental evidence suggests that the cytoskeleton also provides connections between cellular structures and presents a large surface area for interactions of various proteins and signaling molecules. Modulation of the cytoskeletal network may influence cell signaling, ion channels and intracellular calcium levels. Cytoskeleton is thus essential for regulation of cellular functions, cell integrity, and viability. 

Surface charge density may also be an important factor in fiber potency (Bonneau et al. 1986 Davis et al. 1988). In some studies, asbestos fibers were observed to interfere with cytokinesis (Jensen and Watson 1999). Fibers found to be translocated near the nucleus can interact with the cytoskeleton and interfere with chromosome segregation (Ault et al. 1995 Malomi et al. 1990) or with micronucleus formation (Lu et al. 1994a). Deletions of chromosome segments (particularly the short arm of chromosome 3 and portions... 

The defect in locomotion and cytokinesis left little doubt that coronin was playing an important role in the actin cytoskeleton but the phenotype did not give a clear indication of what coronin... 

Insall R, MuUcr-Taubenberger A, Machesky L et al. Dynamics of the Dictyostelium Arp2/3 complex in endocytosis, cytokinesis and chemotaxis. Cell Motil Cytoskeleton 2001 50(3) 115-128. 

The inability of coronin cells to divide properly under axenic conditions points to a role of coronin in cell division and illustrates that various, probably independent, actin-based mechanisms are involved in guaranteeing proper cytokinesis. In conclusion, the defects in cell growth, locomotion and cytokinesis show that coronin is involved in more than a single function of the actin system and suggest that the protein plays a general role in the reorganization of the actin cytoskeleton. " ... 

Fukui Y, Inoue S. Cell division in Dictyostehum with special emphasis on actomyosin organization in cytokinesis. Cell Motil Cytoskeleton 1991 18(l) 41-54. 

A Lim protein involved in the progression of cytokinesis and regulation of the mitotic spindle. CellMotil. Cytoskeleton B6, 130-139... 

Grellier P, Sinou V, Garreau-de Loubresse N et al. Selective and reversible effects of vinca alkaloids on Trypanosoma cruzi epimastigote forms Blockage of cytokinesis without inhibition of the organelle duplication. Cell Motil Cytoskeleton 1999 42 36-47. 

Many biological effects have been observed by the cytochalasans. The most well-documented ones result from an influence on cellular processes, such as intracellular motility, exo- and endocytosis, and cytokinesis, and is based on the interference with actin filament network formation. This is due to interaction with actin (705), one of the key components of the cytoskeleton, leading to inhibition of cytokinesis (cell division) without any influence on karyokinesis (nuclear division). Thus, multinucleated cells were observed after treatment of proliferating cells with... 

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