Herpes simplex virus type 2 UL14 gene product has heat shock protein (HSP)-like functions

Abstract

The HSV-2 UL14 gene encodes a 32 kDa protein that is a minor component of the viral tegument. The protein relocates other viral proteins such as VP26 and UL33 protein into the nuclei of transiently coexpressing cells (Yamauchi et al., 2001). We found that the protein shared some characteristics of heat shock proteins (HSPs) or molecular chaperones, such as nuclear translocation upon heat shock, ATP deprivation and osmotic shock. Interestingly, a significant homology over a stretch of 15 amino acids was found between an N-terminal region of HSV UL14 protein and the substrate-binding domain of Hsp70 family proteins. Two arginine residues in this region were important for nuclear translocation of VP26. In addition, overexpression of UL14 protein increased the activity of coexpressed firefly luciferase, which suggested that the protein functioned in the folding of newly synthesized luciferase. We thus conclude that UL14 protein can act as a chaperone-like protein in a singly expressed state.