Schematic representation of the XB130 and AFAP protein structures. The N-terminal region of XB130 includes several tyrosine phosphorylation sites and a proline-rich sequence that may interact with Src homology (SH) 2 and SH3 domain-containing proteins. The middle portion harbors two pleckstrin homology (PH) domains, while the C-terminal region contains a coiled-coil domain. A common feature of XB130 (818aa) and AFAP (730aa) is the presence of potential SH2, SH3-binding sites and two PH domains. A coiled-coil domain of XB130 shares partial similarity with the leucine zipper domain and in AFAP.