Transcription factor involved in epithelial development. Binds directly to the consensus DNA sequence 5'-AACCGGTT-3' (PubMed:12175488, PubMed:18288204, PubMed:29309642). Important regulator of DSG1 in the context of hair anchorage and epidermal differentiation, participates in the maintenance of the skin barrier. There is no genetic interaction with GRHL3, no functional cooperativity due to diverse target gene selectivity during epithelia development (By similarity). Functions as transcription activator. May function as a repressor in tissues where both isoform 1 and isoform 2 are expressed. Binds DNA as homodimer (PubMed:29309642). Homodimer, also forms heterodimers with GRHL2 or GRHL3 (PubMed:12175488, PubMed:12549979, PubMed:29309642). Isoform 1 is highly expressed in brain, pancreas, tonsil, placenta and kidney. Isoform 2 is highly expressed in brain and liver. Expressed at very low levels in non-steroidogenic cells. Expressed in fetal liver and brain. GRHL genes (GRHL1, GRHL2 and GRHL3) show a paradoxal lack of redundancy despite their extensive sequence identity in the DNA-binding and protein dimerization domains and the fact that the core consensus DNA binding sites are identical. They have related but remarkably different functions during embryogenesis because of their differential spatiotemporal expression patterns during development. Belongs to the grh/CP2 family. Grainyhead subfamily.