Cell cycle-dependent morphological changes in the actin cytoskeleton induced by agents which elevate cyclic AMP

1995 ◽  
Vol 19 (9) ◽  
pp. 769-776 ◽  
Author(s):  
C McNamee
Keyword(s):  
Cell Cycle ◽  
Cyclic Amp ◽  
Actin Cytoskeleton ◽  
Morphological Changes ◽  
Cycle Dependent

scholarly journals The 95F unconventional myosin is required for proper organization of the Drosophila syncytial blastoderm.

1995 ◽  
Vol 129 (6) ◽  
pp. 1575-1588 ◽  
Author(s):  
V Mermall ◽  
K G Miller
Keyword(s):  
Cell Cycle ◽  
Motor Activity ◽  
Actin Cytoskeleton ◽  
Three Dimensional ◽  
Nuclear Morphology ◽  
Unconventional Myosin ◽  
A Cell ◽  
Cytoskeletal Function ◽  
Cycle Dependent

The 95F myosin, a class VI unconventional myosin, associates with particles in the cytoplasm of the Drosophila syncytial blastoderm and is required for the ATP- and F-actin-dependent translocation of these particles. The particles undergo a cell cycle-dependent redistribution from domains that surround each nucleus in interphase to transient membrane invaginations that provide a barrier between adjacent spindles during mitosis. When 95F myosin function is inhibited by antibody injection, profound defects in syncytial blastoderm organization occur. This disorganization is seen as aberrant nuclear morphology and position and is suggestive of failures in cytoskeletal function. Nuclear defects correlate with gross defects in the actin cytoskeleton, including indistinct actin caps and furrows, missing actin structures, abnormal spacing of caps, and abnormally spaced furrows. Three-dimensional examination of embryos injected with anti-95F myosin antibody reveals that actin furrows do not invaginate as deeply into the embryo as do normal furrows. These furrows do not separate adjacent mitoses, since microtubules cross over them. These inappropriate microtubule interactions lead to aberrant nuclear divisions and to the nuclear defects observed. We propose that 95F myosin function is required to generate normal actin-based transient membrane furrows. The motor activity of 95F myosin itself and/or components within the particles transported to the furrows by 95F myosin may be required for normal furrows to form.

scholarly journals Nucleocytoplasmic Shuttling of the Cdc42p Exchange Factor Cdc24p

2000 ◽  
Vol 148 (6) ◽  
pp. 1115-1122 ◽  
Author(s):  
Aljoscha Nern ◽  
Robert A. Arkowitz
Keyword(s):  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Nuclear Import ◽  
Vegetative Growth ◽  
Nuclear Export ◽  
Nuclear Accumulation ◽  
Nucleocytoplasmic Shuttling ◽  
Exchange Factor ◽  
Cycle Dependent ◽  
Necessary And Sufficient

Cdc24p, the GDP/GTP exchange factor for the regulator of actin cytoskeleton Cdc42p, localizes to sites of polarized growth. Here we show that Cdc24p shuttles in and out of the yeast nucleus during vegetative growth. Far1p is necessary and sufficient for nuclear accumulation of Cdc24p, suggesting that its nuclear import occurs via an association with Far1p. Nuclear export is triggered either by entry into the cell cycle or by mating pheromone. As Far1p is degraded upon entry into the cell cycle, cell cycle–dependent export of Cdc24p occurs in the absence of Far1p, whereas during mating similar export kinetics indicate that a Cdc24p–Far1p complex is exported. Our results suggest that the nucleus serves as a store of preformed Cdc24p–Far1p complex which is required for chemotropism.

scholarly journals In Vivo Analysis of the Domains of Yeast Rvs167p Suggests Rvs167p Function Is Mediated Through Multiple Protein Interactions

Genetics ◽  
1999 ◽  
Vol 152 (3) ◽  
pp. 881-893 ◽  
Author(s):  
Karen Colwill ◽  
Deborah Field ◽  
Lynda Moore ◽  
James Friesen ◽  
Brenda Andrews
Keyword(s):  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Protein Interactions ◽  
Morphological Changes ◽  
Sh3 Domain ◽  
Minor Effect ◽  
Cell Cycle Regulators ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bar Domain ◽  
Two Hybrid

Abstract Morphological changes during cell division in the yeast Saccharomyces cerevisiae are controlled by cell-cycle regulators. The Pcl-Pho85p kinase complex has been implicated in the regulation of the actin cytoskeleton at least in part through Rvs167p. Rvs167p consists of three domains called BAR, GPA, and SH3. Using a two-hybrid assay, we demonstrated that each region of Rvs167p participates in protein-protein interactions: the BAR domain bound the BAR domain of another Rvs167p protein and that of Rvs161p, the GPA region bound Pcl2p, and the SH3 domain bound Abp1p. We identified Rvs167p as a Las17p/Bee1p-interacting protein in a two-hybrid screen and showed that Las17p/Bee1p bound the SH3 domain of Rvs167p. We tested the extent to which the Rvs167p protein domains rescued phenotypes associated with deletion of RVS167: salt sensitivity, random budding, and endocytosis and sporulation defects. The BAR domain was sufficient for full or partial rescue of all rvs167 mutant phenotypes tested but not required for the sporulation defect for which the SH3 domain was also sufficient. Overexpression of Rvs167p inhibits cell growth. The BAR domain was essential for this inhibition and the SH3 domain had only a minor effect. Rvs167p may link the cell cycle regulator Pcl-Pho85p kinase and the actin cytoskeleton. We propose that Rvs167p is activated by phosphorylation in its GPA region by the Pcl-Pho85p kinase. Upon activation, Rvs167p enters a multiprotein complex, making critical contacts in its BAR domain and redundant or minor contacts with its SH3 domain.

scholarly journals The Tap42-Protein Phosphatase Type 2A Catalytic Subunit Complex Is Required for Cell Cycle-Dependent Distribution of Actin in Yeast

2003 ◽  
Vol 23 (9) ◽  
pp. 3116-3125 ◽  
Author(s):  
Huamin Wang ◽  
Yu Jiang
Keyword(s):  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Rho Gtpase ◽  
Wide Spectrum ◽  
Protein Phosphatases ◽  
Interacting Protein ◽  
Cellular Processes ◽  
Cellular Events ◽  
Negative Role ◽  
Cycle Dependent

ABSTRACT In Saccharomyces cerevisiae, the Tor proteins mediate a wide spectrum of growth-related cellular processes in response to nutrients. The pleiotropic role of the Tor proteins is mediated, at least in part, by type 2A protein phosphatases (PP2A) and 2A-like protein phosphatases. Tor-mediated signaling activity promotes the interaction of phosphatase-interacting protein Tap42 with PP2A and 2A-like protein phosphatases. The distinct complexes formed between Tap42 and different phosphatases mediate various cellular events and modulate phosphorylation levels of many downstream factors in the Tor pathway in a Tor-dependent and rapamycin-sensitive manner. In this study, we demonstrate that the interaction between Tap42 and the catalytic subunits of PP2A (PP2Ac) is required for cell cycle-dependent distribution of actin. We show that mutations in PP2Ac and Tap42 that perturb the interaction cause random distribution of actin during the cell cycle and that overexpression of the Rho2 GTPase suppresses the actin defects associated with the mutants. Our findings suggest that the Tap42-PP2Ac complex regulates the actin cytoskeleton via a Rho GTPase-dependent mechanism. In addition, we provide evidence that PP2A activity plays a negative role in controlling the actin cytoskeleton and, possibly, in regulation of the G2/M transition of the cell cycle.

scholarly journals Effect of indomethacin on cell cycle dependent cyclic AMP fluxes in tobacco BY-2 cells

FEBS Letters ◽  
1998 ◽  
Vol 422 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Hashimul Ehsan ◽  
Jean-Philippe Reichheld ◽  
Luc Roef ◽  
Erwin Witters ◽  
Filip Lardon ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclic Amp ◽  
Cycle Dependent

Cell cycle dependent modulation of insulin and IGF I receptor binding to human Burkitt type ALL cells

1987 ◽  
Vol 116 (3_Suppl) ◽  
pp. S81
Author(s):  
U. VETTER ◽  
W. HARTMANN ◽  
H. HITZLER ◽  
W. HEIT ◽  
J. SCHLICKENRIEDER ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Receptor Binding ◽  
Igf I ◽  
Cycle Dependent
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