Streptococcus pneumoniae (the Pneumococcus), is a commensal gram-positive bacterium that can cause pneumonia, meningitis or septicemia under certain conditions. During a specific physiological state called 'competence', S. pneumoniae develops natural transformation and can incorporate exogenous DNA into its genome to promote genetic diversification and drive evolution. In the pneumococcus, competent cells exhibit a transient delay in the cell division process. It is thought that this delay allows the cells to complete the final stages of transformation without compromising the integrity of their genome (Berge et al. 2017). ComM, a membrane protein produced during competence and localized at the septum, is necessary and sufficient to inhibit cell division. However, its mechanism of action remains unknown. Here we investigated the underlying links between ComM and the cell division and peptidoglycan (PG) synthesis machineries of S. pneumoniae using a combination of high-resolution fluorescence microscopy and interactomics approaches.