Life Sciences Research for Lifelong Health

Simon Cook

Research Summary

One of the keys to understanding lifelong health is to understand the signalling pathways that operate inside cells and govern key fate decisions such as cell death, cell survival, cell division or cell senescence (collectively cell longevity).  These signalling pathways involve enzymes called ‘protein kinases’ that attach phosphate groups to specific cellular proteins, thereby controlling their activity, location or abundance. In this way protein kinases orchestrate the cellular response to growth factors, nutrient availability or stress and damage.

Ageing results in part from the imbalance between cellular damage, accrued throughout life, and the progressive decline in stress response and repair pathways. We are interested in how protein kinases function in stress responses, the removal of damaged cellular components (e.g. autophagy, see also Nicholas Ktistakis and Oliver Florey) and the control of cellular lifespan. We believe this will enhance our understanding of how the normal declines in these processes drive ageing.

Signalling pathways are frequently de-regulated in certain age-related diseases – notably in cancer, inflammation and neurodegeneration – and many protein kinases are attractive drug targets. Consequently we translate our basic knowledge of signalling through collaborations with charities and pharmaceutical companies (e.g. AstraZeneca and MISSION Therapeutics).

Latest Publications

Maintenance of the marginal-zone B cell compartment specifically requires the RNA-binding protein ZFP36L1.
Newman R, Ahlfors H, Saveliev A, Galloway A, Hodson DJ, Williams R, Besra GS, Cook CN, Cunningham AF, Bell SE, Turner M

RNA-binding proteins of the ZFP36 family are best known for inhibiting the expression of cytokines through binding to AU-rich elements in the 3' untranslated region and promoting mRNA decay. Here we identified an indispensable role for ZFP36L1 as the regulator of a post-transcriptional hub that determined the identity of marginal-zone B cells by promoting their proper localization and survival. ZFP36L1 controlled a gene-expression program related to signaling, cell adhesion and locomotion; it achieved this in part by limiting expression of the transcription factors KLF2 and IRF8, which are known to enforce the follicular B cell phenotype. These mechanisms emphasize the importance of integrating transcriptional and post-transcriptional processes by RNA-binding proteins for maintaining cellular identity among closely related cell types.

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Nature immunology, , 1529-2916, , 2017

PMID: 28394372

RNA-binding proteins ZFP36L1 and ZFP36L2 promote cell quiescence.
Galloway A, Saveliev A, Łukasiak S, Hodson DJ, Bolland D, Balmanno K, Ahlfors H, Monzón-Casanova E, Mannurita SC, Bell LS, Andrews S, Díaz-Muñoz MD, Cook SJ, Corcoran A, Turner M

Progression through the stages of lymphocyte development requires coordination of the cell cycle. Such coordination ensures genomic integrity while cells somatically rearrange their antigen receptor genes [in a process called variable-diversity-joining (VDJ) recombination] and, upon successful rearrangement, expands the pools of progenitor lymphocytes. Here we show that in developing B lymphocytes, the RNA-binding proteins (RBPs) ZFP36L1 and ZFP36L2 are critical for maintaining quiescence before precursor B cell receptor (pre-BCR) expression and for reestablishing quiescence after pre-BCR-induced expansion. These RBPs suppress an evolutionarily conserved posttranscriptional regulon consisting of messenger RNAs whose protein products cooperatively promote transition into the S phase of the cell cycle. This mechanism promotes VDJ recombination and effective selection of cells expressing immunoglobulin-μ at the pre-BCR checkpoint.

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Science (New York, N.Y.), 352, 1095-9203, 453-9, 2016

PMID: 27102483

Tumor cells with KRAS or BRAF mutations or ERK5/MAPK7 amplification are not addicted to ERK5 activity for cell proliferation.
Lochhead PA, Clark J, Wang LZ, Gilmour L, Squires M, Gilley R, Foxton C, Newell DR, Wedge SR, Cook SJ

ERK5, encoded by MAPK7, has been proposed to play a role in cell proliferation, thus attracting interest as a cancer therapeutic target. While oncogenic RAS or BRAF cause sustained activation of the MEK1/2-ERK1/2 pathway, ERK5 is directly activated by MEK5. It has been proposed that RAS and RAF proteins can also promote ERK5 activation. Here we investigated the interplay between RAS-RAF-MEK-ERK and ERK5 signaling and studied the role of ERK5 in tumor cell proliferation in 2 disease-relevant cell models. We demonstrate that although an inducible form of CRAF (CRAF:ER*) can activate ERK5 in fibroblasts, the response is delayed and reflects feed-forward signaling. Additionally, oncogenic KRAS and BRAF do not activate ERK5 in epithelial cells. Although KRAS and BRAF do not couple directly to MEK5-ERK5, ERK5 signaling might still be permissive for proliferation. However, neither the selective MEK5 inhibitor BIX02189 or ERK5 siRNA inhibited proliferation of colorectal cancer cells harbouring KRAS(G12C/G13D) or BRAF(V600E). Furthermore, there was no additive or synergistic effect observed when BIX02189 was combined with the MEK1/2 inhibitor Selumetinib (AZD6244), suggesting that ERK5 was neither required for proliferation nor a driver of innate resistance to MEK1/2 inhibitors. Finally, even cancer cells with MAPK7 amplification were resistant to BIX02189 and ERK5 siRNA, showing that ERK5 amplification does not confer addiction to ERK5 for cell proliferation. Thus ERK5 signaling is unlikely to play a role in tumor cell proliferation downstream of KRAS or BRAF or in tumor cells with ERK5 amplification. These results have important implications for the role of ERK5 as an anti-cancer drug target.

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Cell cycle (Georgetown, Tex.), 15, 1551-4005, 506-18, 2016

PMID: 26959608

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Keywords

cell biology
protein kinases
signalling
stress responses

Group Members

Latest Publications

Maintenance of the marginal-zone B cell compartment specifically requires the RNA-binding protein ZFP36L1.

Newman R, Ahlfors H, Saveliev A

Nature immunology
1529-2916: (2017)

PMID: 28394372

RNA-binding proteins ZFP36L1 and ZFP36L2 promote cell quiescence.

Galloway A, Saveliev A, Łukasiak S

Science (New York, N.Y.)
352 1095-9203:453-9 (2016)

PMID: 27102483

Tumor cells with KRAS or BRAF mutations or ERK5/MAPK7 amplification are not addicted to ERK5 activity for cell proliferation.

Lochhead PA, Clark J, Wang LZ

Cell cycle (Georgetown, Tex.)
15 1551-4005:506-18 (2016)

PMID: 26959608

Maternal DNA Methylation Regulates Early Trophoblast Development.

Branco MR, King M, Perez-Garcia V

Developmental cell
36 1878-1551:152-63 (2016)

PMID: 26812015

MEK1 and MEK2 inhibitors and cancer therapy: the long and winding road.

Caunt CJ, Sale MJ, Smith PD

Nature reviews. Cancer
15 1474-1768:577-92 (2015)

PMID: 26399658

Identification of DYRK1B as a substrate of ERK1/2 and characterisation of the kinase activity of DYRK1B mutants from cancer and metabolic syndrome.

Ashford AL, Dunkley TP, Cockerill M

Cellular and molecular life sciences : CMLS
1420-9071: (2015)

PMID: 26346493