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Protein kinase activity of Tel1p and Mec1p, two Saccharomyces cerevisiae proteins related to the human ATM protein kinase

2000; National Academy of Sciences; Volume: 97; Issue: 25 Linguagem: Inglês

10.1073/pnas.250475697

1091-6490

Julia C. Mallory, Thomas D. Petes,

Genomics and Chromatin Dynamics

The Saccharomyces cerevisiae proteins Tel1p and Mec1p are involved in telomere length regulation and cellular responses to DNA damage. The closest relative of these proteins is the human A taxia T elangiectasia M utated (ATM) protein, a wortmannin-sensitive protein kinase that primarily phosphorylates serines in an SQ motif. We constructed yeast strains containing functional epitope-tagged versions of Tel1p and Mec1p. We showed that immunoprecipitated Tel1p and Mec1p were capable of in vitro phosphorylation of the mammalian protein PHAS-I ( P hosphorylated H eat and A cid S table protein). These activities are sensitive to wortmannin. Tel1p phosphorylates serine in an SQ motif in PHAS-I. Mutations in the kinase domains of Tel1p and Mec1p result in loss of in vitro kinase activity and the in vivo phenotypes associated with the null tel1 and mec1 mutations.