PTTG1（pituitary tumor-transforming 1），癌症关联基因，基因ID：9232，编码蛋白是酵母安全蛋白的同系物，它能阻止海毒蛋白促进姐妹染色单体分离。它是一种后期促进复合物（APC）底物，在激活APC之前与一种丝氨酸结合。该基因产物具有体外转化活性和体内致瘤活性，在各种肿瘤中有很高的表达。该基因产物含有2个pxxp基序，这些基序对其转化和致瘤活性以及对碱性成纤维细胞生长因子表达的刺激都是必需的。它还包含APC降级所需的销毁盒（D盒）。编码蛋白的酸性C端区域可以作为一个激活域。基因产物主要是一种细胞溶质蛋白，尽管它部分位于细胞核内。三个编码相同蛋白质的转录变体被发现用于这个基因。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 the gene is highly expressed in various tumors. The gene product 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。