The formation of CXCR2-NHERF1-PLC beta 3 macromolecular complex in pancreatic cancer cells regulates CXCR2 signaling activity and plays an important role in tumor proliferation and invasion. We previously have shown that disruption of the NHERF1-mediated CXCR2-PLC beta 3 interaction abolishes the CXCR2 signaling cascade and inhibits pancreatic tumor growth in vitro and in vivo. Here we report the crystal structure of the NHERF1 PDZ1 domain in complex with the C-terminal PLC beta 3 sequence. The structure reveals that the PDZ1-PLC beta 3 binding specificity is achieved by numerous hydrogen bonds and hydrophobic contacts with the last four PLC beta 3 residues contributing to specific interactions. We also show that PLC beta 3 can bind both NHERF1 PDZ1 and PDZ2 in pancreatic cancer cells, consistent with the observation that the peptide binding pockets of these PDZ domains are highly structurally conserved. This study provides an understanding of the structural basis for the PDZ-mediated NHERF1-PLC beta 3 interaction that could prove valuable in selective drug design against CXCR2-related cancers. (C) 2014 Published by Elsevier Inc.