Vestigial-like family member 1 (VGLL1): An emerging candidate in tumor progression.

Vestigial-like family member 1 (VGLL1), a product of an X-linked gene (VGLL1), belongs to a family of transcriptional co-activators including VGLL2, VGLL3 and VGLL4. These proteins are called vestigial-like because of the structural and functional similarities with the Drosophila ortholog vestigial (vg). VGLL1 is usually expressed in human placenta, and has also been detected in many aggressive cancers. For this reason, it is called an onco-placental protein. It can bind and activate the TEA-domain containing transcription factors TEAD1-4, and the interaction is mediated through a conserved 'valine-x-x-histidine-phenylalanine' domain (VxxHF, x denotes any amino acid) present in VGLL1 protein. Prior studies indicate a pro-tumorigenic role for this protein in several cancers including carcinoma of the breast. This review aims at summarizing our present knowledge about the functions of VGLL1, and the mechanisms that regulate its expression in cancer.