A conserved polylysine motif in CD86 cytoplasmic tail is necessary for cytoskeletal association and effective co-stimulation

► In this study we report that CD86 is attached to the cytoskeleton of antigen presenting cells. ► We identified sequence determinants of CD86 that are important for association to the cytoskeleton. ► Association of CD86 to the cytoskeleton is not involved in APC:T cell conjugate formation. ► CD86 association to the cytoskeleton is required for optimal activation of T cells.