Adapter protein involved in tyrosine kinase and CD28 signaling (By similarity). May be a modulator of the apoptotic response through its ability to affect mitochondrial stability. Interacts with FES and TNK2. Predominantly expressed in spleen and thymus. Appears not to be expressed in heart, brain, liver, kidney, embryo, lung and ovary. May be phosphorylated by FES and ACK1.