Depolarization of the actin cytoskeleton is a specific phenotype in Saccharomyces cerevisiae

1998 ◽  
Vol 111 (17) ◽  
pp. 2689-2696 ◽  
Author(s):  
T.S. Karpova ◽  
S.L. Moltz ◽  
L.E. Riles ◽  
U. Guldener ◽  
J.H. Hegemann ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Environmental Factors ◽  
Actin Cytoskeleton ◽  
Slow Growth ◽  
Specific Response ◽  
Number Of Genes ◽  
Chromosome I ◽  
Harsh Conditions

The yeast actin cytoskeleton is polarized during most of the cell cycle. Certain environmental factors and mutations are associated with depolarization of the actin cytoskeleton. Is depolarization of the actin cytoskeleton a specific response, or is it a nonspecific reaction to harsh conditions or poor metabolism? If depolarization is a nonspecific response, then any mutation that slows growth should induce depolarization. In addition, the number of genes with the depolarization phenotype should constitute a relatively large part of the genome. To address this question, we determined the effect of slow growth on the actin cytoskeleton, and we determined the frequency of mutations that affect the actin cytoskeleton. Eight mutants with slow growth showed no defect in actin polarization, indicating that slow growth alone is not sufficient to cause depolarization. Among 273 viable haploids disrupted for ORFs of chromosome I and VIII and 950 viable haploids with random genome disruptions, none had depolarization of the cytoskeleton. We conclude that depolarization of the actin cytoskeleton is a specific phenotype.

scholarly journals The Saccharomyces cerevisiae SDA1 gene is required for actin cytoskeleton organization and cell cycle progression

2000 ◽  
Vol 113 (7) ◽  
pp. 1199-1211
Author(s):  
G. Buscemi ◽  
F. Saracino ◽  
D. Masnada ◽  
M.L. Carbone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Replication ◽  
Actin Cytoskeleton ◽  
Cell Cycle Progression ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Cycle Progression ◽  
Cytoskeleton Organization ◽  
Actin Cytoskeleton Organization

The organization of the actin cytoskeleton is essential for several cellular processes. Here we report the characterization of a Saccharomyces cerevisiae novel gene, SDA1, encoding a highly conserved protein, which is essential for cell viability and is localized in the nucleus. Depletion or inactivation of Sda1 cause cell cycle arrest in G(1) by blocking both budding and DNA replication, without loss of viability. Furthermore, sda1-1 temperature-sensitive mutant cells arrest at the non-permissive temperature mostly without detectable structures of polymerized actin, although a normal actin protein level is maintained, indicating that Sda1 is required for proper organization of the actin cytoskeleton. To our knowledge, this is the first mutation shown to cause such a phenotype. Recovery of Sda1 activity restores proper assembly of actin structures, as well as budding and DNA replication. Furthermore we show that direct actin perturbation, either in sda1-1 or in cdc28-13 cells released from G(1) block, prevents recovery of budding and DNA replication. We also show that the block in G(1) caused by loss of Sda1 function is independent of Swe1. Altogether our results suggest that disruption of F-actin structure can block cell cycle progression in G(1) and that Sda1 is involved in the control of the actin cytoskeleton.

scholarly journals BED1, a gene encoding a galactosyltransferase homologue, is required for polarized growth and efficient bud emergence in Saccharomyces cerevisiae.

1996 ◽  
Vol 132 (1) ◽  
pp. 137-151 ◽  
Author(s):  
G Mondésert ◽  
S I Reed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Dependent Manner ◽  
Polarized Growth ◽  
Checkpoint Control ◽  
Wild Type ◽  
Ellipsoidal Shape ◽  
Bud Emergence ◽  
Morphogenesis Checkpoint

The ellipsoidal shape of the yeast Saccharomyces cerevisiae is the result of successive isotropic/apical growth switches that are regulated in a cell cycle-dependent manner. It is thought that growth polarity is governed by the remodeling of the actin cytoskeleton that is itself under the control of the cell cycle machinery. The cell cycle and the morphogenesis cycle are tightly coupled and it has been recently suggested that a morphogenesis/polarity checkpoint control monitors bud emergence in order to maintain the coupling of these two events (Lew, D. J., and S. I. Reed. 1995. J. Cell Biol. 129:739-749). During a screen based on the inability of cells impaired in the budding process to survive when the morphogenesis checkpoint control is abolished, we identified and characterized BED1, a new gene that is required for efficient budding. Cells carrying a disrupted allele of BED1 no longer have the wild-type ellipsoidal shape characteristic of S. cerevisiae, are larger than wild-type cells, are deficient in bud emergence, and depend upon an intact morphogenesis checkpoint control to survive. These cells show defects in polarized growth despite the fact that the actin cytoskeleton appears normal. Our results suggest that Bed1 is a type II membrane protein localized in the endoplasmic reticulum. BED1 is significantly homologous to gma12+, a S. pombe gene coding for an alpha-1,2,-galactosyltransferase, suggesting that glycosylation of specific proteins or lipids could be important for signaling in the switch to polarized growth and in bud emergence.

scholarly journals Pak-Family Kinases Regulate Cell and Actin Polarization Throughout the Cell Cycle of Saccharomyces cerevisiae

1999 ◽  
Vol 147 (4) ◽  
pp. 845-856 ◽  
Author(s):  
Stephen P. Holly ◽  
Kendall J. Blumer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Yeast Cell ◽  
Fluorescent Protein ◽  
Surface Growth ◽  
Yeast Cell Cycle ◽  
Cortical Actin ◽  
Bud Emergence

During the cell cycle of the yeast Saccharomyces cerevisiae, the actin cytoskeleton and cell surface growth are polarized, mediating bud emergence, bud growth, and cytokinesis. We have determined whether p21-activated kinase (PAK)-family kinases regulate cell and actin polarization at one or several points during the yeast cell cycle. Inactivation of the PAK homologues Ste20 and Cla4 at various points in the cell cycle resulted in loss of cell and actin cytoskeletal polarity, but not in depolymerization of F-actin. Loss of PAK function in G1 depolarized the cortical actin cytoskeleton and blocked bud emergence, but allowed isotropic growth and led to defects in septin assembly, indicating that PAKs are effectors of the Rho–guanosine triphosphatase Cdc42. PAK inactivation in S/G2 resulted in depolarized growth of the mother and bud and a loss of actin polarity. Loss of PAK function in mitosis caused a defect in cytokinesis and a failure to polarize the cortical actin cytoskeleton to the mother-bud neck. Cla4–green fluorescent protein localized to sites where the cortical actin cytoskeleton and cell surface growth are polarized, independently of an intact actin cytoskeleton. Thus, PAK family kinases are primary regulators of cell and actin cytoskeletal polarity throughout most or all of the yeast cell cycle. PAK-family kinases in higher organisms may have similar functions.

scholarly journals Identification of Genes Controlling Growth Polarity in the Budding Yeast Saccharomyces cerevisiae: A Possible Role of N-Glycosylation and Involvement of the Exocyst Complex

Genetics ◽  
1997 ◽  
Vol 147 (2) ◽  
pp. 421-434 ◽  
Author(s):  
G Mondésert ◽  
D J Clarke ◽  
S I Reed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Cell Cycle Progression ◽  
Cellular Systems ◽  
Surface Growth ◽  
Polarized Growth ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cycle Progression

The regulation of secretion polarity and cell surface growth during the cell cycle is critical for proper morphogenesis and viability of Saccharomyces cerevisiae. A shift from isotropic cell surface growth to polarized growth is necessary for bud emergence and a repolarization of secretion to the bud neck is necessary for cell separation. Although alterations in the actin cytoskeleton have been implicated in these changes in secretion polarity, clearly other cellular systems involved in secretion are likely to be targets of cell cycle regulation. To investigate mechanisms coupling cell cycle progression to changes in secretion polarity in parallel with and downstream of regulation of actin polarization, we implemented a screen for mutants defective specifically in polarized growth but with normal actin cytoskeleton structure. These mutants fell into three classes: those partially defective in N-glycosylation, those linked to specific defects in the exocyst, and a third class neither defective in glycosylation nor linked to the exocyst. These results raise the possibility that changes in N-linked glycosylation may be involved in a signal linking cell cycle progression and secretion polarity and that the exocyst may have regulatory functions in coupling the secretory machinery to the polarized actin cytoskeleton.

TOR2 Is Part of Two Related Signaling Pathways Coordinating Cell Growth in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Stephen B Helliwell ◽  
Isabelle Howald ◽  
Nik Barbet ◽  
Michael N Hall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Growth ◽  
Actin Cytoskeleton ◽  
Signaling Pathways ◽  
Growth Defect ◽  
G1 Arrest ◽  
Class A ◽  
Class B

Abstract The Saccharomyces cerevisiae genes TOR1 and TOR2 encode phosphatidylinositol kinase homologs. TOR2 has two essential functions. One function overlaps with TOR1 and mediates protein synthesis and cell cycle progression. The second essential function of TOR2 is unique to TOR2 and mediates the cell-cycle-dependent organization of the actin cytoskeleton. We have isolated temperature-sensitive mutants that are defective for either one or both of the two TOR2 functions. The three classes of mutants were as follows. Class A mutants, lacking only the TOR2-unique function, are defective in actin cytoskeleton organization and arrest within two to three generations as small-budded cells in the G2/M phase of the cell cycle. Class B mutants, lacking only the TOR-shared function, and class C mutants, lacking both functions, exhibit a rapid loss of protein synthesis and a G1 arrest within one generation. To define further the two functions of TOR2, we isolated multicopy suppressors that rescue the class A or B mutants. Overexpression of MSS4, PKC1, PLC1, RHO2, ROM2, or SUR1 suppressed the growth defect of a class A mutant. Surprisingly, overexpression of PLC1 and MSS4 also suppressed the growth defect of a class B mutant. These genes encode proteins that are involved in phosphoinositide metabolism and signaling. Thus, the two functions (readouts) of TOR2 appear to involve two related signaling pathways controlling cell growth.

scholarly journals The EH-domain-containing protein Pan1 is required for normal organization of the actin cytoskeleton in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (9) ◽  
pp. 4897-4914 ◽  
Author(s):  
H Y Tang ◽  
M Cai
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Calcium Binding ◽  
Ectopic Expression ◽  
Binding Domain ◽  
Actin Binding ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Eh Domain

Normal cell growth and division in the yeast Saccharomyces cerevisiae involve dramatic and frequent changes in the organization of the actin cytoskeleton. Previous studies have suggested that the reorganization of the actin cytoskeleton in accordance with cell cycle progression is controlled, directly or indirectly, by the cyclin-dependent kinase Cdc28. Here we report that by isolating rapid-death mutants in the background of the Start-deficient cdc28-4 mutation, the essential yeast gene PAN1, previously thought to encode the yeast poly(A) nuclease, is identified as a new factor required for normal organization of the actin cytoskeleton. We show that at restrictive temperature, the pan1 mutant exhibited abnormal bud growth, failed to maintain a proper distribution of the actin cytoskeleton, was unable to reorganize actin the cytoskeleton during cell cycle, and was defective in cytokinesis. The mutant also displayed a random pattern of budding even at permissive temperature. Ectopic expression of PAN1 by the GAL promoter caused abnormal distribution of the actin cytoskeleton when a single-copy vector was used. Immunofluorescence staining revealed that the Pan1 protein colocalized with the cortical actin patches, suggesting that it may be a filamentous actin-binding protein. The Pan1 protein contains an EF-hand calcium-binding domain, a putative Src homology 3 (SH3)-binding domain, a region similar to the actin cytoskeleton assembly control protein Sla1, and two repeats of a newly identified protein motif known as the EH domain. These findings suggest that Pan1, recently recognized as not responsible for the poly(A) nuclease activity (A. B. Sachs and J. A. Deardorff, erratum, Cell 83:1059, 1995; R. Boeck, S. Tarun, Jr., M. Rieger, J. A. Deardorff, S. Muller-Auer, and A. B. Sachs, J. Biol. Chem. 271:432-438, 1996), plays an important role in the organization of the actin cytoskeleton in S. cerevisiae.

scholarly journals CDC42 and CDC43, two additional genes involved in budding and the establishment of cell polarity in the yeast Saccharomyces cerevisiae.

1990 ◽  
Vol 111 (1) ◽  
pp. 131-142 ◽  
Author(s):  
A E Adams ◽  
D I Johnson ◽  
R M Longnecker ◽  
B F Sloat ◽  
J R Pringle
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mitotic Spindles ◽  
Yeast Saccharomyces Cerevisiae ◽  
Continue Growth

Budding in the yeast Saccharomyces cerevisiae involves a polarized deposition of new cell surface material that is associated with a highly asymmetric disposition of the actin cytoskeleton. Mutants defective in gene CDC24, which are unable to bud or establish cell polarity, have been of great interest with regard to both the mechanisms of cellular morphogenesis and the mechanisms that coordinate cell-cycle events. To gain further insights into these problems, we sought additional mutants with defects in budding. We report here that temperature-sensitive mutants defective in genes CDC42 and CDC43, like cdc24 mutants, fail to bud but continue growth at restrictive temperature, and thus arrest as large unbudded cells. Nearly all of the arrested cells appear to begin nuclear cycles (as judged by the occurrence of DNA replication and the formation and elongation of mitotic spindles), and many go on to complete nuclear division, supporting the hypothesis that the events associated with budding and those of the nuclear cycle represent two independent pathways within the cell cycle. The arrested mutant cells display delocalized cell-surface deposition associated with a loss of asymmetry of the actin cytoskeleton. CDC42 maps distal to the rDNA on chromosome XII and CDC43 maps near lys5 on chromosome VII.

scholarly journals A Role for Actin, Cdc1p, and Myo2p in the Inheritance of Late Golgi Elements in Saccharomyces cerevisiae

2001 ◽  
Vol 153 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Olivia W. Rossanese ◽  
Catherine A. Reinke ◽  
Brooke J. Bevis ◽  
Adam T. Hammond ◽  
Irina B. Sears ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Fluorescence Microscopy ◽  
Actin Cytoskeleton ◽  
Polarized Growth ◽  
Independent Manner ◽  
Multiple Alleles ◽  
Actin Cables ◽  
Type V

In Saccharomyces cerevisiae, Golgi elements are present in the bud very early in the cell cycle. We have analyzed this Golgi inheritance process using fluorescence microscopy and genetics. In rapidly growing cells, late Golgi elements show an actin-dependent concentration at sites of polarized growth. Late Golgi elements are apparently transported into the bud along actin cables and are also retained in the bud by a mechanism that may involve actin. A visual screen for mutants defective in the inheritance of late Golgi elements yielded multiple alleles of CDC1. Mutations in CDC1 severely depolarize the actin cytoskeleton, and these mutations prevent late Golgi elements from being retained in the bud. The efficient localization of late Golgi elements to the bud requires the type V myosin Myo2p, further suggesting that actin plays a role in Golgi inheritance. Surprisingly, early and late Golgi elements are inherited by different pathways, with early Golgi elements localizing to the bud in a Cdc1p- and Myo2p-independent manner. We propose that early Golgi elements arise from ER membranes that are present in the bud. These two pathways of Golgi inheritance in S. cerevisiae resemble Golgi inheritance pathways in vertebrate cells.

scholarly journals Saccharomyces cerevisiae Arc35p works through two genetically separable calmodulin functions to regulate the actin and tubulin cytoskeletons

2000 ◽  
Vol 113 (3) ◽  
pp. 521-532 ◽  
Author(s):  
C. Schaerer-Brodbeck ◽  
H. Riezman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Actin Cytoskeleton ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Restrictive Temperature ◽  
Metaphase Arrest ◽  
A Cell ◽  
Synthetically Lethal

Analysis of the arc35-1 mutant has revealed previously that this component of the Arp2/3 complex is involved in organization of the actin cytoskeleton. Further characterization uncovered a cell division cycle phenotype with arrest as large-budded cells. Cells with correctly positioned metaphase spindles accumulated at the restrictive temperature. The observed metaphase arrest most likely occurs by activation of the spindle assembly checkpoint, because arc35-1 was synthetically lethal with a deletion of BUB2. Arc35p activity is required late in G(1) for its cell cycle function. Both the actin and microtubule defects of arc35-1 can be suppressed by overexpression of calmodulin. Analysis of a collection of ts cmd1 mutants for their ability to suppress the actin and/or microtubule defect revealed that the two defects observed in arc35-1 are genetically separable. These data suggest that the actin defect is probably not the cause of the microtubule defect.

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