Strongly activates transcription when bound to HCFC1. Suppresses the expression of HSV proteins in cells infected with the virus in a HCFC1-dependent manner. Also suppresses the HCFC1-dependent transcriptional activation by CREB3 and reduces the amount of CREB3 in the cell. Able to down-regulate expression of some cellular genes in CREBZF-expressing cells. Interacts with HCFC1; the interaction inhibits CREB3 transcriptional activity (PubMed:10871379, PubMed:15705566). Interacts with CREB3; the interaction occurs only in combination with HCFC1 (PubMed:15705566). Colocalizes in promyelocytic leukemia protein nuclear bodies (PML-NB) with CREB3 and HCFC1. In adults, expressed most abundantly in heart, liver and skeletal muscle, moderately abundant in kidney and pancreas, and barely detectable in lung. In fetal tissues, expressed most abundantly in kidney and very low amounts in heart, lung and liver. Named 'Zhangfei' after a legendary Chinese warrior who was contemporary with Luman in around 220 AD. Belongs to the bZIP family. ATF subfamily. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.