Host Cell Factor C1 Regulator 1 (HCFC1R1)

HCF-1 is a cellular protein required by VP16 to activate the herpes simplex virus (HSV) immediate-early genes. VP16 and LZIP share a tetrapeptide HCF-binding motif recognized by the beta-propeller domain of HCF-1. A new cellular HCF-1 beta-propeller domain binding protein, termed HPIP, which contains a functional HCF-binding motif and a leucine-rich nuclear export sequence. HPIP shuttles between the nucleus and cytoplasm in a CRM1-dependent manner and that overexpression of HPIP leads to accumulation of HCF-1 in the cytoplasm. These data suggest that HPIP regulates HCF-1 activity by modulating its subcellular localization. Furthermore, HPIP-mediated export may provide the pool of cytoplasmic HCF-1 required for import of virion-derived VP16 into the nucleus.