Investigation of Protein Complex CXCR2-PDZ-RhoGEF through Expression, Purification and Crystallization

Abstract

The PDZ domain, found in various scaffolding proteins, is responsible for protein linkages in a signaling pathway that allow multicellular reorganization. Once such protein containing the PDZ domain is RhoGEF, which is responsible for activating GTPases that lead to the initiation of downstream RhoA protein responsible for cytoskeleton reorganization. As a multi-domain protein, the upstream interactions that occurs between GPCRs and the PDZ domain, result in the activation of the other domains such as LH, DH and PH domains, allowing the signaling pathway to progress. The present study investigated the possibility of the GPCR CXCR2 to create a peptide link with the PDZ domain of RhoGEF. Studies have shown peptide linkages occurring between CXCR2 and the PDZ domain on other proteins, however, no study has investigated the possible interaction between CXCR2 and PDZ-RhoGEF. The protein interaction was expressed in E. coli cells, and purification was completed using the HisTrap Ni2+ chromatography column, the desalting column, and the size-exclusion column. Analysis through crystallization of pure protein resulted in insufficient crystals for X-ray crystallography analysis. Results suggested that a peptide linkage interaction between CXCR2 and PDZRhoGEF does not occur.