Adaptor proteins are specialized molecules that play a crucial role in cellular signaling. They act as connectors, linking different proteins together to facilitate communication within the cell. By bringing together various signaling pathways, adaptor proteins help transmit signals from the cell surface to the interior, influencing processes like growth, differentiation, and immune responses. These proteins often contain specific domains that allow them to bind to multiple partners, enhancing the efficiency of signal transduction. For example, in the context of the immune system, adaptor proteins are essential for activating T cells and B cells, ensuring a coordinated response to pathogens.