Abstract
The spindle checkpoint regulates the cell division cycle by keeping cells with defective spindles from leaving mitosis. In the two-hybrid system, three proteins that are components of the checkpoint, Mad1, Mad2, and Mad3, were shown to interact with Cdc20, a protein required for exit from mitosis. Mad2 and Mad3 coprecipitated with Cdc20 at all stages of the cell cycle. The binding of Mad2 depended on Mad1 and that of Mad3 on Mad1 and Mad2. Overexpression of Cdc20 allowed cells with a depolymerized spindle or damaged DNA to leave mitosis but did not overcome the arrest caused by unreplicated DNA. Mutants in Cdc20 that were resistant to the spindle checkpoint no longer bound Mad proteins, suggesting that Cdc20 is the target of the spindle checkpoint.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Anaphase
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Anaphase-Promoting Complex-Cyclosome
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Antigens, CD
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Cadherins
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Calcium-Binding Proteins / metabolism
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Carrier Proteins*
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Cdc20 Proteins
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Cdh1 Proteins
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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DNA Damage
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DNA Replication
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Fungal Proteins / chemistry
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Fungal Proteins / metabolism*
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Ligases / metabolism
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Mad2 Proteins
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Mitosis*
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Molecular Sequence Data
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Mutation
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Nuclear Proteins / metabolism
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Phosphoproteins / metabolism
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Repressor Proteins*
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Saccharomyces cerevisiae / cytology*
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins*
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Spindle Apparatus / metabolism*
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Ubiquitin-Protein Ligase Complexes*
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Ubiquitin-Protein Ligases
Substances
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Antigens, CD
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CDC20 protein, S cerevisiae
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CDH1 protein, human
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Cadherins
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Calcium-Binding Proteins
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Carrier Proteins
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Cdc20 Proteins
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Cdh1 Proteins
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Cell Cycle Proteins
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Fungal Proteins
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MAD1 protein, S cerevisiae
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MAD1L1 protein, human
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MAD2 protein, S cerevisiae
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Mad2 Proteins
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Nuclear Proteins
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Phosphoproteins
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Repressor Proteins
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Saccharomyces cerevisiae Proteins
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Ubiquitin-Protein Ligases
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Ligases