Structure of the Pho85-Pho80 CDK-cyclin complex of the phosphate-responsive signal transduction pathway.

The ability to sense and respond appropriately to environmental changes is a primary requirement of all living organisms. In response to phosphate limitation, Saccharomyces cerevisiae induces transcription of a set of genes involved in the regulation of phosphate acquisition from the ambient environment. A signal transduction pathway (the PHO pathway) ...
mediates this response, with Pho85-Pho80 playing a vital role. Here we report the X-ray structure of Pho85-Pho80, a prototypic structure of a CDK-cyclin complex functioning in transcriptional regulation in response to environmental changes. The structure revealed a specific salt link between a Pho85 arginine and a Pho80 aspartate that makes phosphorylation of the Pho85 activation loop dispensable and that maintains a Pho80 loop conformation for possible substrate recognition. It further showed two sites on the Pho80 cyclin for high-affinity binding of the transcription factor substrate (Pho4) and the CDK inhibitor (Pho81) that are markedly distant to each other and the active site.
Mesh Terms:
Binding Sites, Crystallography, X-Ray, Cyclin-Dependent Kinases, Cyclins, DNA-Binding Proteins, Enzyme Activation, Enzyme Inhibitors, Models, Molecular, Mutant Proteins, Phenylalanine, Phosphates, Phosphorylation, Protein Binding, Protein Structure, Secondary, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction, Structure-Activity Relationship, Substrate Specificity, Transcription Factors
Mol. Cell
Date: Nov. 30, 2007
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