In vitro interaction between coxsackievirus B3 VP1 protein and human pleckstrin homology domain retinal protein (PHR1).

Coxsackievirus B3 (CVB3) infection causes central nervous system diseases including aseptic meningitis and encephalitis. To understand the mechanism of this virus, a yeast two-hybrid system was used to screen cellular proteins from a human heart cDNA library. The results revealed that the human Pleckstrin Homology Domain Retinal protein (PHR1), a PH domain-containing protein with low expression in the heart and high expression in the brain, interacts with CVB3 VP1, a major structural protein of CVB3. Yeast mating assays and in vitro coimmunoprecipitation verified the interaction between CVB3 VP1 and PHR1. An α-galactosidase assay indicated that of α-galactosidase activity was higher in positive clones than in controls suggesting a strong interaction. Furthermore, assay of deletion mutants defined the minimal region of PHR1 required for its interaction with VP1 as amino acids 95-172 and two regions of VP1 required for its interaction with PHR1 as amino acids 729-767 and 811-859. The results revealed multiple binding sites between PHR1 and CVB3 VP1 and suggested that the strong interaction between these two proteins might play an important role in central nervous system disease in the human brain.