The Nupr1 Benzethonium Chloride protein is an IDP, which binds DNA and is a substrate for protein kinase A; phosphorylation seems to increase the content of residual structure, and the phosphorylated species also binds DNA. The exact function of Nupr1 is unknown, although it has been involved as a scaffold protein in transcription, and as an essential element of the defence system of the cell and in cell-cycle regulation. Furthermore, Nupr1 expression controls pancreatic cancer cell migration, invasion and adhesion, three processes required for metastasis through CDC42, a major regulator of cytoskeleton organization. Also, Nupr1 seems to play a major role in pancreatic tumorigenesis since the oncogenic KrasG12D expression in mice pancreas is unable to promote precancerous lesions in the absence of Nupr1 expression. A complete account of the different functions of Nupr1 can be found in the literature. We have shown that in pancreatic cells Nupr1 regulates the DNA-repairing activity of MSL1, which is one of the functions where MSL1 is involved. Furthermore, surface plasmon resonance and two-yeast-hybrid techniques suggest that there is an interaction between MSL1 and Nupr1. Although the MSL complex members have been studied during the last decade, the detailed molecular interactions of the members of the complex remain unknown, and the experimental structural features of the isolated, intact MSL1 remain elusive. The only region of MSL1 whose structure has been solved is that of the coiled-coil motif. Given, its DNA-repairing activity modulated by Nupr1 and its apparent importance during tumorigenesis, we have embarked in a description of the interaction between both proteins, and of both with DNA. In this work, first, we established that both Nupr1 and MSL1 proteins are recruited and form a complex into the nucleus in response to DNA-damage; we found that this complex was essential for cell survival in response to cisplatin damage. Second, we expressed, refolded and purified intact MSL1 with a TRX-tag. The protein was an oligomeric IDP, as judged by ITC and thermal denaturation experiments followed by circular dichroism and fluorescence. Next, we studied, by using different biophysical and spectroscopic techniques, the affinities of Nupr1 for MSL1 in the absence and the presence of etoposide-damagedDNA. And finally, we described the binding site of Nupr1 towards MSL1 and DNA by triple-resonance NMR experiments. First, our results suggest that the function of MSL1 was exquisitely modulated to recognize damaged DNA. Although it may seem surprising that such diverse insects have radiated onto a nutritionally-poor resource, mutualistic symbioses between bacteria and their eukaryotic hosts allow animals to feed on a diversity of diets that would otherwise be inaccessible to the host. Such beneficial endosymbionts can provide essential amino acids and vitamins lacking in the host diet, or they can synthesize novel enzymes, such as cellulases and hydrolases, to degrade otherwise indigestible materials like cellulose, lignin, and chitin. These mutualisms are seen in animals ranging from cellulose feeding vertebrates to wood-, sap-, and blood-feeding insects. In insects, mutualistic endosymbionts frequently supplement the host with essential amino acids and vitamins Yunaconitine missing from their food source. This supplementation may be provided primarily by one symbiont species, as in the aphid-Buchnera system, or by a community of symbionts, such as in termites. No matter the number of beneficial endosymbionts, the faithful transmission of these specific mutualists from parent to offspring is essential for offspring survival. There are two broad categories of transmission: vertical transmission, where symbionts are acquired from the parent, and horizontal transmission, where they are not.