TI  -  <prot>Cdi1</prot> , a human G1 and S phase protein phosphatase that associates with
       <prot>Cdk2</prot> .
PG  - 791-803
AB  - We used the interaction trap, a yeast genetic selection for interacting
      proteins, to isolate human <prot>cyclin-dependent kinase interactor 1</prot> (<prot>Cdi1</prot>). In
      yeast,     <prot>Cdi1</prot>    interacts with  cyclin-dependent kinases, including human  <prot>Cdc2</prot> ,
       <prot>Cdk2</prot> , and  <prot>Cdk3</prot> , but not with <prot>Cdk4</prot>. In HeLa cells,  <prot>Cdi1</prot>  is expressed at the
      G1 to S transition, and the protein forms stable complexes with  <prot>Cdk2</prot> . <prot>Cdi1</prot>
      bears weak sequence similarity to known tyrosine and dual specificity
      phosphatases. In vitro, <prot>Cdi1</prot> removes phosphate from tyrosine residues in
      model substrates, but a mutant protein that bears a lesion in the putative
      active site cysteine does not. Overexpression of wild-type <prot>Cdi1</prot> delays
      progression through the cell cycle in yeast and HeLa cells; delay is
      dependent on <prot>Cdi1</prot> phosphatase activity. These experiments identify  <prot>Cdi1</prot>  as
      a novel type of protein phosphatase that forms complexes with
       cyclin-dependent kinases .
AD  - Department of Molecular Biology, Massachusetts General Hospital, Boston
