Eva-Maria Schilling


B3 Interference of the viral effector proteins pp71 and IE1 with ND10-mediated intrinsic immunity against human cytomegalovirus infections

Principal investigator
Thomas Stamminger

Yves Muller

Mechanism of de-SUMOylation by the regulatory protein IE1 of HCMV

Human cytomegalovirus (HCMV), a member of the family of β-herpesviruses, is a ubiquitous human pathogen of increasing seroprevalence. Infections with HCMV mostly proceed asymptomatic in immunocompetent persons. However, in immunocompromised persons and newborns it can lead to severe diseases and life-threatening complications. To avoid infection, the human immune system evolved several defense strategies. Our group is interested in a structure called nuclear domain 10 (ND10) that is able to silence immediate-early (IE) gene expression thereby establishing a first line of intrinsic antiviral defense. ND10 are mainly built by the promyelocytic leukemia protein (PML) and the SUMOylation of PML is indispensable for the dot-like ND10 structure. However, the ND10-mediated defense mechanism is counteracted by the immediate-early protein 1 (IE1) of HCMV. During infection, IE1 directly interacts with PML through its globular core domain, induces PML deSUMOylation, and mediates disruption of ND10. To date, the exact mode of IE1 action still remains elusive. The aim of this project is, on the one hand, to clarify which regions of IE1 and PML are involved in the protein-protein interaction and, on the other hand, to unravel the underlying mechanism of IE1-mediated PML deSUMOylation. Based on the crystal structure of the IE1 globular core domain, which was recently solved by our group in collaboration with Prof. Yves Muller, we are planning to further narrow down the regions required for PML binding and subsequent PML deSUMOylation. Despite great efforts during the last two decades, it was not possible to unravel the mechanism of IE1 mediated PML deSUMOylation and ND10 disruption. There are two main questions which have to be answered: Is IE1 mediating deSUMOylation of PML either in a proteolytic way or via the prevention of de novo SUMOylation? Are there any cellular proteins for the deSUMOylating activity required? To address these questions we will perform in vitro SUMOylation assays as well as in vivo experiments. Additionally, we are searching for novel interaction partners of IE1 which could not only explain the scenario of IE1-mediated PML deSUMOylation but also provide the basis for further projects.

Figure: Schematic representation of the IE1-mediated PML deSUMOylation and ND10 disruption during HCMV infection



Scherer, M., Kling, S., Sevvana, M., Otto, V., Schilling, E.M., Stump, J.D., Müller, R., Reuter, N., Sticht, H., Muller, Y.A. & Stamminer, T. (2014). Crystal Structure of Cytomegalovirus IE1 Protein Reveals Targeting of TRIM Family Member PML via Coiled-Coil Interactions. PLoS Pathog 10(11), e1004512.

Jung, J., Loy, K., Schilling, E.M., Röther, M., Brauner, J.M., Huth, T., Schlötzer-Schrehardt, U., Alzheimer, C., Kornhuber, J., Welzel, O. & Groemer, T.W. (2014). The antidepressant fluoxetine mobilizes vesicles to the recycling pool of rat hippocampal synapses during high activity. Mol. Neurobiol. 49, 916-930.

Baron, J., Tarnow, C., Mayoli-Nüssle, D., Schilling, E., Meyer, D., Hammami, M., Schwalm, F., Steinmetzer, T., Guan, Y., Garten, W., Klenk, H.D. & Böttcher-Friebertshäuser, E. (2013). Matriptase, HAT, and TMPRSS2 activate the hemagglutinin of H9N2 influenza A viruses. J. Virol. 87, 1811-1820.



October 2015 Methods in Molecular Virology, Institute of Virology, Erlangen, Germany
”Unraveling the Mechanism of IE1-Mediated PML DeSUMOylation”
October 2015 2nd International SFB 796 Conference: Mechanisms of microbial host cell manipulation: From plants to humans, Erlangen, Germany
”Unraveling the Mechanism of IE1-Mediated PML DeSUMOylation”
July 2015 7th Annual Retreat, Erlangen School of Molecular Communication, Schloss Hirschberg, Beilngries, Germany
”Interplay between HCMV IE1 and host restriction factor PML”
July 2014 39th Annual International Herpesvirus Workshop, Kobe, Japan
”Defining Minimal Structural Requirements for the Interaction Between Human Cytomegalovirus Immediate-Early Protein 1 (IE1) and the Cellular Restriction Factor PML”
December 2013

13th Retreat, GK 1071 "Viruses of the Immune System", Lenggries-Fall, Germany
”Unraveling IE1-mediated deSUMOylation – novel clues”

September 2013 4th International Symposium "Regulators of Adaptive Immunity", Erlangen, Germany
Requirements for the binding of human cytomegalovirus immediate early protein 1 (IE1) to the cellular restriction factor PML
September 2013 5th European Congress of Virology, Lyon, France
Requirements for the binding of human cytomegalovirus immediate early protein 1 (IE1) to the cellular restriction factor PML
March 2013 12th Retreat, GK 1071 "Viruses of the Immune System", Schlaifhausen, Germany
The interaction between IE1 and PML – a way to overcome intrinsic immunity against Cytomegalovirus