Add reference We used a knock-in (KI) mouse expressing SLP-76 with a C-terminal One-Strep-Tag (OST). Such a system allowed the replacement in the genome of SLP-76 by its tagged version and its expression in physiological amounts. Then, by combining high affinity purification and label-free quantitative proteomics, we report here the first description of the SLP76 interactome in resting and activated primary cultured mast cells derived from mice expressing an OST at the C-terminus of SLP-76 (Slp76OST/OST mice).