Src family kinase activity drives cytomegalovirus reactivation by recruiting MOZ histone acetyltransferase activity to the viral promoter

Liane Dupont,Lily Du,Madeleine Poulter,Stephanie Choi,Megan Mcintosh,Matthew B Reeves

doi:10.1074/jbc.ra119.009667

Liane Dupont, Lily Du + Show 4 more

Open Access

https://doi.org/10.1074/jbc.ra119.009667

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Abstract

Human cytomegalovirus (HCMV) latency and reactivation rely on a complex interplay between cellular differentiation, cell signaling pathways, and viral gene functions. HCMV reactivation in dendritic cells (DCs) is triggered by IL-6 and extracellular signal-regulated kinase (ERK)–mitogen-activated protein kinase signaling. However, activation of the same pathway fails to reactivate HCMV in other myeloid cell types, despite this signaling axis being active in those cells. We hypothesized that IL-6–induced ERK activation initiates the changes in chromatin structure required for viral reactivation but that a concomitant signal is necessary to complete the changes in chromatin structure required for gene expression to occur. Using a differential phosphoproteomics approach in cells that do or do not support IL-6–induced viral reactivation, we identified the concomitant activation of an Src family kinase (SFK), hematopoietic cell kinase (HCK), specifically in DCs in response to IL-6. Pharmacological and genetic inhibition of HCK activity indicated that HCK is required for HCMV reactivation. Furthermore, the HCK/SFK activity was linked to recruitment of the monocytic leukemia zinc finger protein (MOZ) histone acetyltransferase to the viral promoter, which promoted histone acetylation after ERK-mediated histone phosphorylation. Importantly, pharmacological and genetic inhibition of MOZ activity prevented reactivation. These results provide an explanation for the selective activation of viral gene expression in DCs by IL-6, dependent on concomitant SFK and ERK signaling. They also reveal a previously unreported role for SFK activity in the regulation of chromatin structure at promoters in eukaryotic cells via MOZ histone acetyltransferase activity.

Highlights

Human cytomegalovirus (HCMV) latency and reactivation rely on a complex interplay between cellular differentiation, cell signaling pathways, and viral gene functions
We show that extracellular signal-regulated kinase (ERK)–MAPK– driven reactivation of HCMV viral gene expression depends on the concomitant activation of Src family kinase (SFK) signaling in monocyte-derived dendritic cells (MoDCs)
We took advantage of a previous study we had performed, in which we demonstrated that, when we altered the culture conditions and promoted monocytes to differentiate into immature monocyte-derived Langerhans-like cells (MoLCs), they did not support IL-6 –induced reactivation, unlike what was observed in MoDCs [21]

Summary

Introduction

Human cytomegalovirus (HCMV) latency and reactivation rely on a complex interplay between cellular differentiation, cell signaling pathways, and viral gene functions. We show that ERK–MAPK– driven reactivation of HCMV viral gene expression depends on the concomitant activation of Src family kinase (SFK) signaling in monocyte-derived dendritic cells (MoDCs).

Results

Conclusion