Nascent polypeptide associated complex (NAC) proteins bind to newly synthesized polypeptide chains from ribosome and are involved in various physiological processes. An in vitro pull-down assay demonstrated that the previously identified NAC protein interacts with phytochromes. Phytochrome-interacting NAC protein (PNAC) was expressed in the cytosol, and translocation of the PNAC protein into nucleus by irradiation was not observed. These findings suggest that PNAC is a possible cytosolic partner protein to phytochromes. Histochemical analysis of PNAC promoter-${eta}$-glucuronidase (GUS) transgenic plants showed that PNAC expression was increased by light treatment, especially red light, indicating that phytochromes likely modulate PNAC gene expression.