The function of GLI1 (GLI family zinc finger 1, ENSG00000111087) is as follows. Transcription activator that acts as a key effector of the smoothened signaling pathway, and which plays a role in craniofacial development and digital development, as well as development of the central nervous system and gastrointestinal tract (PubMed:10806483, PubMed:11238441, PubMed:19706761, PubMed:19878745, PubMed:24076122, PubMed:24217340, PubMed:24311597, PubMed:28973407). Binds to the DNA consensus sequence 5'-GACCACCCA-3' (PubMed:2105456, PubMed:24217340, PubMed:2832761, PubMed:8378770). Activated in response to smoothened signaling: in presence of hedgehog (DHH, IHH or SHH) and subsequent activation of smoothened, GLI1 translocates to the nucleus and promotes expression of target genes (PubMed:2105456). In contrast to GLI2 and GLI3, does not contain a repressor domain and only acts as a transcription activator (PubMed:10075717). {ECO:0000269|PubMed:10075717, ECO:0000269|PubMed:10806483, ECO:0000269|PubMed:11238441, ECO:0000269|PubMed:19706761, ECO:0000269|PubMed:19878745, ECO:0000269|PubMed:2105456, ECO:0000269|PubMed:24076122, ECO:0000269|PubMed:24217340, ECO:0000269|PubMed:24311597, ECO:0000269|PubMed:2832761, ECO:0000269|PubMed:28973407, ECO:0000269|PubMed:8378770}. [Isoform 2]: Acts as a transcriptional activator, but activates a different set of genes than isoform 1 (PubMed:19706761). Activates expression of CD24, unlike isoform 1 (PubMed:19706761). .