Cytomegaloviral proteins pUL50 and pUL53 are associated with the nuclear lamina and interact with cellular protein kinase C.

Human cytomegalovirus-encoded pUL50 and pUL53 belong to a group of conserved herpesviral nuclear proteins. This study describes: (i) the co-localization of pUL50 with components of the nuclear lamina such as lamins A/C and lamin B receptor by double immunofluorescent staining, (ii) a strong pUL50-mediated relocalization of pUL53 from a diffuse nuclear pattern towards a nuclear rim localization, (iii) a direct interaction between pUL50 and pUL53, as well as between pUL50 and protein kinase C (PKC), shown by yeast two-hybrid and co-immunoprecipitation analyses, (iv) in vitro phosphorylation of pUL50, which is highly suggestive of PKC activity, and finally (v) partial relocalization of PKC by pUL50/pUL53 from its main cytoplasmic localization to a marked nuclear lamina accumulation. These data suggest a role for pUL50 and pUL53 in the recruitment of PKC, an event that is considered to be important for cytomegalovirus-induced distortion of the nuclear lamina.