Transcriptional repressor. Binds to the canonical and non-canonical E box sequences 5'-CACGTG-3' (By similarity). Binds DNA as a heterodimer with TCFL4/MLX. Expressed in liver, heart, kidney, cerebellum and intestinal tissues. Phosphorylation at Ser-556 by AMPK inactivates the DNA-binding activity. WBSCR14 is located in the Williams-Beuren syndrome (WBS) critical region. WBS results from a hemizygous deletion of several genes on chromosome 7q11.23, thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region. Haploinsufficiency of WBSCR14 may be the cause of certain cardiovascular and musculo-skeletal abnormalities observed in the disease. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.