Description
Securin, also known as pituitary tumor-transforming 1 or EAP1 is a protein that in humans is encoded by the PTTG1 gene. The encoded protein is a homolog of yeast securin proteins, which prevent separins from promoting sister chromatid separation. It is an anaphase-promoting complex(APC) substrate that associates with a separin until activation of the APC. The gene product has transforming activity in vitro and tumorigenic activity in vivo, and is highly expressed in various tumors. Securin contains 2 PXXP motifs, which are required for its transforming and tumorigenic activities, as well as for its stimulation of basic fibroblast growth factor expression. It also contains a destruction box(D box) that is required for its degradation by the APC. The acidic C-terminal region of the encoded protein can act as a transactivation domain. It is mainly a cytosolic protein, although it partially localizes in the nucleus