Gadd45 Proteins in Immunity 2.0.

To protect the host against invading pathogens such as viruses, bacteria, and parasites as well as against tumor cells, the immune system of vertebrates has to distinguish between self and non-self, but also between harmless and dangerous. To do so, the immune system developed an innate and an adaptive branch that provide immediate and long-lasting protection, respectively. Furthermore, the immune system is composed of different cell types, which are specialized to combat different threats, and it is located at strategic locations to manage surveillance of the whole body. Therefore, immune cells need to communicate with each other. Growth arrest and DNA damage-inducible 45 (Gadd45) proteins are important components of intracellular signaling networks that convey messages from other cells in the receiving cell into biological responses. Within the 7 years that have passed since my first overview about Gadd45 proteins in the immune system, substantial progress has been made in our understanding of the immune system and with respect to Gadd45 proteins. Therefore, it is time for an update-Gadd45 proteins in immunity 2.0. In order to put Gadd45 proteins into the context of the immune system, I will first give a brief introduction into the immune system. Afterwards, I will give a brief introduction into Gadd45 proteins. For deeper insight, I refer to the other chapters of this book. The third section discusses the role of Gadd45 proteins in myeloid and lymphoid cells. The last two sections will be on the function of Gadd45 proteins in infection, autoimmunity, and tumor immunology.