Probable adapter protein involved in signaling pathways. Interacts with the SH2 and SH3 domains of various signaling proteins when it is phosphorylated. May promote FYN activation, possibly by disrupting intramolecular SH3-dependent interactions. Interacts with LYN (By similarity). Interacts with the SH2 and SH3 domains of FYN when phosphorylated. Also interacts with GRB2 and PIK3R1 when phosphorylated. A small proportion is membrane-associated. Strongly expressed in brain and kidney, expressed at intermediate levels skin and heart, and weakly expressed in thymus. Not expressed in liver and spleen. Phosphorylated on tyrosines by LYN (By similarity). Phosphorylated on tyrosines by FYN. Belongs to the TOM1 family.