Transcriptional repressor involved in multiple aspects of cortical development, including neuronal migration, laminar and areal identity, and axonal projection (PubMed:25232744, PubMed:30250039). As transcriptional repressor of FEZF2, it blocks the formation of the corticospinal (CS) tract from layer 6 projection neurons, thereby restricting the origin of CS axons specifically to layer 5 neurons (By similarity). Homodimer (PubMed:25232744). Part of a complex containing CASK, TBR1 and TSPYL2; may modulate gene expression in response to neuronal synaptic activity (By similarity). Interacts with FOXP2 (PubMed:25232744, PubMed:30250039). Interacts with FOXP1 (PubMed:30250039). Interacts with BCL11A (PubMed:30250039). Brain. The disease is caused by variants affecting the gene represented in this entry.