Good morning, good afternoon, good night! Welcome to the 8th international webinars series For those who don't already know, these webinars have been set up by the international Biometals society and the journal Biometals with the help of Cassyni platform. • The aim of these webinars is to promote research in the field of metal in biology and to encourage the interdisciplinary exchange of information at international level. Mammalian metals homeostasis in the spotlight today! Welcome our two speakers First, Elizabeth Nolan from the Massachusetts institute of technology, in Cambridge, USA, will be talking about A fascinating protein, the calprotectin involved in nutritional immunity by metal withholding activity to prevent metal acquisition by the invading bacterial pathogens… So I suppose we'll be hearing about calcium ions and transition metal, such as iron, sequestion by Calprotection. High Faecal calciprotectin concentration can be a marker of various intestinal pathologies. Liz together with Janet J. Y. Peet published a review in Biometals in 2023 on Post‑translational modifications on the metal‑sequestering protein calprotectin.

The second speaker is Svetlana Lutsenko from the Johns Hopkins medical faculty, in Baltimore. Her group is focused on the molecular mechanisms of copper homeostasis in normal and diseased cells. Copper and its various redox state are involved in several essential biological processes and its homeostasis should be tightly controlled. I am excited to ear more about the recent data, some unpublished that Svetlana is going to talk about today (part not recorded) !

This presentation will focus on the metal-sequestering host defense protein calprotectin (CP). Its coordination chemistry and and the working model for how CP contributes to metal limitation in the extracellular space will be described along with our current thinking regarding the importance of integrating environmental complexity and relevant physiological variables into this model. Two case studies highlighting consequences of the environment on CP structure and function will be presented. One case study will be focused on the interplay of CP, Fe and bacterial metabolites and the other on oxidative post-translational modifications.

In mammalian cells, copper is utilized for energy production, protection against radical mediated damage, signaling and for determining cell identity. During cell differentiation, requirements for copper increase. At the same time, specific steps in cell differentiation program may require transient decrease of cytosolic copper. This is accomplished by coordinated upregulation and trafficking of copper transporters. This presentation will summarize the data on the role of copper homeostasis in cell differentiation and morphogenesis. The in vitro and in vivo (in mice) data will be shown illustrating how copper misbalance influence the ability of cells to acquire characteristic cell morphology. Published and unpublished data will be discussed