Role of intrinsic flexibility in signal transduction mediated by the cell cycle regulator, p27Kip1

Charles Galea, Amanda Nourse, Yuefeng Wang, Sivashankar G Sivakolundu, William T Heller, Richard W Kriwacki

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Abstract

p27Kip1 (p27), which controls eukaryotic cell division through interactions with cyclin-dependent kinases (Cdks), integrates and transduces promitogenic signals from various nonreceptor tyrosine kinases by orchestrating its own phosphorylation, ubiquitination and degradation. Intrinsic flexibility allows p27 to act as a conduit for sequential signaling mediated by tyrosine and threonine phosphorylation and ubiquitination. While the structural features of the Cdk/cyclin-binding domain of p27 are understood, how the C-terminal regulatory domain coordinates multistep signaling leading to p27 degradation is poorly understood. We show that the 100-residue p27 C-terminal domain is extended and flexible when p27 is bound to Cdk2/cyclin A. We propose that the intrinsic flexibility of p27 provides a molecular basis for the sequential signal transduction conduit that regulates p27 degradation and cell division. Other intrinsically unstructured proteins possessing multiple sites of posttranslational modification may participate in similar signaling conduits.
Original languageEnglish
Pages (from-to)827 - 838
Number of pages12
JournalJournal of Molecular Biology
Volume376
Issue number3
DOIs
Publication statusPublished - 2008
Externally publishedYes

Cite this

Galea, C., Nourse, A., Wang, Y., Sivakolundu, S. G., Heller, W. T., & Kriwacki, R. W. (2008). Role of intrinsic flexibility in signal transduction mediated by the cell cycle regulator, p27Kip1. Journal of Molecular Biology, 376(3), 827 - 838. https://doi.org/10.1016/j.jmb.2007.12.016