Using synchrotron X-ray fluorescence (SXRF) nano-imaging at ID16A we have previously revealed the functions of Zn and Cu in the cytoskeletal architecture of hippocampal neurons. This result shed a new light on the understanding of Zn and Cu contribution to fundamental neuronal processes such as the morphological plasticity of the synapse. Now we would like to explore if this mechanism applies more generally to other cellular systems. We will use the same methodological approach, validated with neurons, and correlate 40 nm resolution nano-SXRF imaging of element distributions with 40 nm STED (stimulated emission depletion) super resolution imaging of cytoskeletal proteins. Primary human fibroblasts and rat astrocytes will be labelled with silicon-rhodamine tubulin and F-actin fluorogenic probes designed for STED microscopy. The co-localization of Zn with tubulin and Cu with actin would place Zn and Cu at the heart of broad biological processes such as cell differentiation and division.