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An archaeal homolog of the human p53 related protein kinase
Author(s) -
Haile January D.,
Ray W. Keith,
Ben Potters M,
Kennelly Peter J.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a615-a
Subject(s) - casein kinase 1 , biology , casein kinase 2 , cyclin dependent kinase 7 , saccharomyces cerevisiae , kinase , protein kinase a , cyclin dependent kinase 2 , phosphorylation , map2k7 , ask1 , genetics , microbiology and biotechnology , biochemistry , gene
Open reading frame (ORF) sso0433 encodes a protein kinase, SsoPK5, in Sulfolobus solfataricus P2 . The protein kinase has 33% sequence identity to the Homo sapiens p53 related protein kinase (PRPK) and 26% sequence identity to the Saccharomyces cerevisiae Bud32. Both kinases phosphorylate targets involved in cell cycle regulation. For example, PRPK phosphorylates p53. While there is no p53 homolog in S. cerevisiae , Bud32 does phosphorylate human p53 in vitro . Moreover, the knockout of Bud32 exhibits a slow growth phenotype. Given the evolutionary distance between the Archaea and Eukarya, the degree of sequence similarity is unexpectedly high. Therefore, we are exploring whether the function of the archaeal protein kinase is similar to its counterparts in humans and yeast. We hypothesize SsoPK5 targets similar proteins and processes. SsoPK5 phosphorylates several exogenous and endogenous substrates in vitro . These include casein and PCNA1, a sliding clamp. We are also evaluating protein products from ORFs sso0432 , a homolog of S. cerevisiae HamI , and sso0434, S. cerevisiae endopeptidase , as potential targets of SsoPK5. Sso0432 and Sso0434 are of particular interest because they along with SsoPK5 appear to be encoded by an operon. In the future we will determine if the activity of target proteins is altered as a function of the phosphorylation state. Research supported by the National Science Foundation.