X11L2, a new member of the X11 protein family, interacts with Alzheimer's beta-amyloid precursor protein.

We screened proteins for interaction with Alzheimer's beta-amyloid precursor protein (APP) and cloned a new member of the X11 protein family, X11L2. The PID/PTB element of X11L2 protein interacted with the intracellular domain of APP by GST binding assay, and in vivo interaction was confirmed by coimmunoprecipitation from cell extracts overexpressing APP and HA-tagged X11L2. This gene encoded 575 amino acids and the deduced amino acid sequence was highly homologous to rat Mint3. Three protein-protein interaction domains, a PID/PTB and two PDZ elements, were conserved among the X11 protein family, and the N-terminal region of X11L2 protein had several putative SH3 binding motifs, PXXP. Unlike other members of the X11 protein family, X11L2 mRNA was expressed in various tissues.