Saccharomyces cerevisiae Arc35p works through two genetically separable calmodulin functions to regulate the actin and tubulin cytoskeletons.
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.
Schaerer-Brodbeck
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Biozentrum of the University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Riezman
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D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000483:Alleles; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002147:Calmodulin / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D016193:G1 Phase; D015966:Gene Expression Regulation, Fungal; D046911:Macromolecular Substances; D008677:Metaphase; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines; D014404:Tubulin / Q000378:metabolism*
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; C070351:BUB2 protein, S cerevisiae; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002147:Calmodulin; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D029701:Saccharomyces cerevisiae Proteins; D013844:Thiazoles; D053778:Thiazolidines; D014404:Tubulin; C037067:latrunculin A