Involved in transcriptional regulation. Transcriptional activity differed among the various isoforms. All isoforms except isoform 3 seem to suppresses the transcriptional activities of AP-1 and p53/TP53. Tissue specificity:Expressed in all tissues examined. Isoforms are differentially expressed. Isoform 3 and isoform 5 were highly expressed, isoform 4 moderately expressed, isoform 2 lower expression, the lowest expression level was seem with isoform 1.