Actin-based adhesion structures, especially those involved in cell adhesion to the extracellular matrix via integrins that we will call here ABS, are complex molecular assemblies with a wide range of shapes and dynamics. By participating in the remodeling of the extracellular matrix and in cell migration, ABS perform essential functions in many biological processes such as embryonic development, tissue repair, immune response, angiogenesis... The transport of mRNAs and their local translation participate in the spatial and temporal control of protein distribution, notably in the lamellipod, a well-known example of ABS. However, very little is yet known about the diversity of mRNAs enriched in ABS. Furthermore, the mRNAs whose local translation is required for the formation and maintenance of ABS are not known. Finally, although the general mechanisms of mRNA translation initiation and elongation have been characterized, the mechanisms that control local translation remain mostly unidentified. Cell adhesion to the extracellular matrix, extracellular matrix remodeling and cell migration are key processes in cell biology, which also have implications in tissue morphogenesis and organogenesis. This highlights the importance of studying the impact of local mRNA translation on ABS dynamics. In this project, we aim to understand the importance of local translation of mRNAs in the establishment and maintenance of ABS. For this, our consortium combines the expertise in the study of molecular mechanisms controlling the dynamics and functions of different types of ABS with expertise in translation initiation factors, protein synthesis machinery and genome-wide (translatomic) mRNA translation analyses. For this project, we will use 3 models of ABS based on a dynamic branched actin network dependent on the Arp2/3 complex, but with distinct molecular organization, dynamics and functions: the lamellipod of the migrating cell, the invadosomes that remodel the extracellular matrix and the actin ring of osteoclasts that supports their bone resorption apparatus. We will rely on state-of-the-art techniques gathered in our consortium: subcellular laser microdissection combined with proteomics and transcriptomics, local and global detection of protein synthesis, super-resolved microscopy and single molecule imaging, and time-resolved translatomics. We propose: (WP1) to establish and compare the local landscape of mRNAs and proteins in ABS and to characterize the local translation activity of mRNAs during ABS formation; (WP2) to establish the localization and nanoscale dynamics of key components of the translation machinery in ABS, and to assess the impact of intra- and extracellular forces on local translation at ABS; (WP3) to establish the hierarchy of translation events during the assembly of each ABS and to identify the specific translation factors that control protein synthesis in each ABS. In this way, we hope to discover mRNAs whose local translation is key to the maintenance of the different ABS, determine whether the different translation steps occur at the same location or in different subdomains of the ABS, define the mechanisms that couple local translation of mRNAs to the dynamics of the ABS, and identify translation factors and locally translated mRNAs that are critical for the establishment and function of the different ABS.