Function and regulation of ARTD10-dependent mono-ADP-ribosylation in signaling and gene transcription

点击翻译按钮获取中文摘要

Posttranslational modifications (PTMs) of proteins play a key role in the propagation of information in cells. PTMs control the functionality of proteins by altering their properties, including stability, subcellular localization, interaction with other macromolecules, and enzymatic activity. Among the many different known PTMs, ADP-ribosylation is rapidly emerging as a modification that controls central pathways in cells, which are associated with for example inflammation, cancer and neurodegeneration. ADP-ribosylation involves enzymes that transfer ADP-ribose (ADPr) from the cofactor NAD+ onto substrates. We have identified with ARTD10 the first intracellular, resident mono-ADP-ribosyltransferase of mammalian cells and our recent studies provide initial evidence relevant to understand basic features of mono-ADP-ribosylation (MARylation). Our findings suggest that (i) MARylation occurs in cells and controls physiological processes, (ii) is a reversible PTM as we have identified specific macrodomains that hydrolyze the ester bond between the ADPr and the glutamate side chain, (iii) is read by specific protein domains, i.e. macrodomains of ARTD8, and (iv) controls multiple signaling pathways inferred from the identified substrates. While these initial findings provide a framework of basic knowledge, many questions arise that need to be addressed to more fully understand the regulatory potential and the biology of MARylation and the enzymes involved in writing, reading and erasing this PTM. In this proposal we will concentrate on the analysis of specific key questions, whose answers will allow us to further expand our knowledge of the role of MARylation and the enzymes associated with this PTM in the control of specific proteins and pathways and of gene expression. At the center is the interaction of ARTD10-dependent mono-ADP-ribosylated substrates with the macrodomains of ARTD8. We will use and further develop these macrodomains as tools to define MARylation. We will modulate ARTD10 activity, either by overexpression, by knockdown, or by regulating the activity of MAR hydrolases to control MARylation. The mapping of MARylation sites will allow us to further develop the mechanistic aspects of this PTM as a regulator of enzymes such as kinases. Moreover we will evaluate the relevance of the interaction of ARTD8 with ARTD10. Finally we will address the role of ARTD10 and ARTD8 and MARylation in the organization of chromatin and in the regulation of gene transcription to define how this PTM affects the use of genomic information also considering the interplay with other histone marks. With these studies, all based on our own work, we will contribute considerably to our understanding of MARylation and its role in controlling key physiological processes.