1. A novel pocket in 14-3-3ɛ is required to mediate specific complex formation with cdc25C and to inhibit cell cycle progression upon activation of checkpoint pathways
- Author
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Sorab N. Dalal, Prasanna Venkatraman, Amol S. Hosing, Samrat T. Kundu, and Elphine Telles
- Subjects
Models, Molecular ,Gene isoform ,Molecular Sequence Data ,Cell Cycle Proteins ,medicine.disease_cause ,Mice ,In vivo ,Dual-specificity phosphatase ,medicine ,Animals ,Humans ,cdc25 Phosphatases ,Amino Acid Sequence ,Structural motif ,Mitosis ,Phylogeny ,Mutation ,Base Sequence ,biology ,Cell Biology ,G2-M DNA damage checkpoint ,Cell cycle ,Protein Structure, Tertiary ,Rats ,Cell biology ,14-3-3 Proteins ,biology.protein ,Sequence Alignment ,Protein Binding ,Signal Transduction - Abstract
Mitotic progression requires the activity of the dual specificity phosphatase, cdc25C. Cdc25C function is inhibited by complex formation with two 14-3-3 isoforms, 14-3-3epsilon and 14-3-3gamma. To understand the molecular basis of specific complex formation between 14-3-3 proteins and their ligands, chimeric 14-3-3 proteins were tested for their ability to form a complex with cdc25C in vivo. Specific complex formation between cdc25C and 14-3-3epsilon in vivo requires a phenylalanine residue at position 135 (F135) in 14-3-3epsilon. Mutation of this residue to the corresponding residue present in other 14-3-3 isoforms (F135V) leads to reduced binding to cdc25C and a decrease in the ability to inhibit cdc25C function in vivo. Similarly, F135V failed to rescue the incomplete S phase and the G2 DNA damage checkpoint defects observed in cells lacking 14-3-3epsilon. A comparative analysis of the 14-3-3 structures present in the database suggested that the F135 in 14-3-3epsilon was required to maintain the integrity of a pocket that might be involved in secondary interactions with cdc25C. These results suggest that the specificity of the 14-3-3 ligand interaction may be dependent on structural motifs present in the individual 14-3-3 isoforms.
- Published
- 2009