| This cloned cDNA encodes a novel protein with Krppel type zinc fingers designed as ZZaPK ( zinc finger and ZAK associated protein with KRAB domain ) and is widely expressed . ^^^ A novel zinc finger protein , ZZaPK , interacts with ZAK and stimulates the ZAK expressing cells re entering the cell cycle . ^^^ ZZaPK , when it is expressed in cells , is growth promoted and might lead to increasing E2F expression and induce cyclin E / CDK2 activity , which counteracts the ZAK function . ^^^ The model proposed here is that ZAK might play a role as an upstream signal to suppress the ZZaPK function and decrease E2F expression . . ^^^ |