Proteomic Landscape of Tissue-Specific Cyclin E Functions in Vivo.

Junko Odajima,Yasmine Ndassa-Colday,Piotr Jung,Wojciech Michowski,Piotr Sicinski,Larisa Litovchick,Jarrod Marto,Yan Geng,Eugenio Marco,Scott Ficaro,Yaoyu E Wang,James A Decaprio,Siddharth Saini,Bruce E Clurman

doi:10.1371/journal.pgen.1006429

Junko Odajima, Yasmine Ndassa-Colday + Show 12 more

Open Access

https://doi.org/10.1371/journal.pgen.1006429

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Abstract

E-type cyclins (cyclins E1 and E2) are components of the cell cycle machinery that has been conserved from yeast to humans. The major function of E-type cyclins is to drive cell division. It is unknown whether in addition to their ‘core’ cell cycle functions, E-type cyclins also perform unique tissue-specific roles. Here, we applied high-throughput mass spectrometric analyses of mouse organs to define the repertoire of cyclin E protein partners in vivo. We found that cyclin E interacts with distinct sets of proteins in different compartments. These cyclin E interactors are highly enriched for phosphorylation targets of cyclin E and its catalytic partner, the cyclin-dependent kinase 2 (Cdk2). Among cyclin E interactors we identified several novel tissue-specific substrates of cyclin E-Cdk2 kinase. In proliferating compartments, cyclin E-Cdk2 phosphorylates Lin proteins within the DREAM complex. In the testes, cyclin E-Cdk2 phosphorylates Mybl1 and Dmrtc2, two meiotic transcription factors that represent key regulators of spermatogenesis. In embryonic and adult brains cyclin E interacts with proteins involved in neurogenesis, while in adult brains also with proteins regulating microtubule-based processes and microtubule cytoskeleton. We also used quantitative proteomics to demonstrate re-wiring of the cyclin E interactome upon ablation of Cdk2. This approach can be used to study how protein interactome changes during development or in any pathological state such as aging or cancer.

Highlights

E-type cyclins represent components of the core cell cycle machinery
The proliferation of mammalian cells is driven by proteins called cyclins, which bind and activate their catalytic partners, the cyclin-dependent kinases (Cdks)
Whether in addition to their well-established cell cycle roles Etype cyclins perform distinct tissue-specific functions in vivo, in the living mouse. To address this question we developed a system, which combines gene targeting in embryonic stem cells with high-throughput mass spectrometry

Summary

Introduction

E-type cyclins (cyclins E1 and E2, collectively referred to as ‘cyclin E’) represent components of the core cell cycle machinery. The two E-cyclins are encoded by separate genes, but they show substantial amino acid sequence similarity. E-cyclins become upregulated during the late G1 phase. E-cyclins bind and activate their catalytic partner, the cyclin-dependent kinase 2 (Cdk). Cyclin E-Cdk complexes phosphorylate proteins involved in cell cycle progression (the retinoblastoma protein pRB, p107, p130, p27Kip1), centrosome duplication (NPM1, CP110), histone biosynthesis (p220NPAT ) and DNA replication (Cdc, MCMs), thereby driving cell proliferation [1,2]. Consistent with growth-promoting roles for Ecyclins, amplification of the cyclin E1 and/or E2 genes and pathological overexpression of cyclin E proteins were documented in a wide range of human cancer types [1]

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Discussion

Conclusion