Abstract
Cell cycle progression is coupled to cell growth, but the mechanisms that generate growth-dependent cell cycle progression remain unclear. Fission yeast cells enter into mitosis at a defined size due to the conserved cell cycle kinases Cdr1 and Cdr2, which localize to a set of cortical nodes in the cell middle. Cdr2 is regulated by the cell polarity kinase Pom1, suggesting that interactions between cell polarity proteins and the Cdr1-Cdr2 module might underlie the coordination of cell growth and division. To identify the molecular connections between Cdr1/2 and cell polarity, we performed a comprehensive pairwise yeast two-hybrid screen. From the resulting interaction network, we found that the protein Skb1 interacted with both Cdr1 and the Cdr1 inhibitory target Wee1. Skb1 inhibited mitotic entry through negative regulation of Cdr1 and localized to both the cytoplasm and a novel set of cortical nodes. Skb1 nodes were distinct structures from Cdr1/2 nodes, and artificial targeting of Skb1 to Cdr1/2 nodes delayed entry into mitosis. We propose that the formation of distinct node structures in the cell cortex controls signaling pathways to link cell growth and division.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Cell Cycle / genetics
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Cell Cycle / physiology*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cytoplasm / metabolism
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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Immunoblotting
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Methyltransferases / genetics
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Methyltransferases / metabolism
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Microscopy, Confocal
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Mitosis / genetics
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Mitosis / physiology*
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Binding
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Protein Interaction Maps
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism
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Red Fluorescent Protein
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism
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Schizosaccharomyces / physiology*
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism
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Signal Transduction / genetics
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Signal Transduction / physiology*
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Two-Hybrid System Techniques
Substances
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Cell Cycle Proteins
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Luminescent Proteins
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Nuclear Proteins
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Schizosaccharomyces pombe Proteins
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Skb1 protein, S pombe
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Green Fluorescent Proteins
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Methyltransferases
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cdr1 protein, S pombe
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wee1 protein, S pombe
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Protein-Tyrosine Kinases
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Cdr2 protein, S pombe
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Protein Serine-Threonine Kinases