BIRC5
Description
The BIRC5 (baculoviral IAP repeat containing 5) is a protein-coding gene located on chromosome 17.
BIRC5, also called Survivin or baculoviral inhibitor of apoptosis repeat-containing 5, is a protein encoded by the BIRC5 gene in humans. It belongs to the inhibitor of apoptosis (IAP) family and functions to inhibit caspase activation, thereby preventing programmed cell death (apoptosis). Disrupting survivin induction pathways leads to increased apoptosis and decreased tumor growth. Survivin is highly expressed in most human tumors and fetal tissue but absent in fully differentiated cells, suggesting it could be a target for cancer therapies that distinguish between normal and cancerous cells. Survivin expression is tightly regulated by the cell cycle and is only present during the G2-M phase. It interacts with tubulin during mitosis, localizing to the mitotic spindle and potentially contributing to the regulation of mitosis. The precise mechanisms of survivin regulation remain unclear but appear to be linked to the p53 protein. It is a direct target gene of the Wnt pathway and is upregulated by beta-catenin.
BIRC5 is a multifunctional protein with roles in both promoting cell growth and preventing programmed cell death (apoptosis). It is a component of the chromosomal passenger complex (CPC), which is essential for proper chromosome alignment and separation during mitosis and cytokinesis. BIRC5 helps direct the CPC to different locations within the cell during these processes, and it also participates in organizing the spindle fibers that pull chromosomes apart. It is involved in recruiting the CPC to centromeres during early mitosis, and it helps form the mitotic spindle by interacting with other proteins like RAN and TPX2. BIRC5 may also counteract the normal tendency of cells to undergo apoptosis during the G2/M phase of the cell cycle. Its acetylated form can suppress the activity of the STAT3 protein, which regulates gene expression. BIRC5 is an inhibitor of the caspase-3 and caspase-7 enzymes, which are involved in apoptosis. It is also essential for maintaining the structure and function of mitochondria, which are vital for cell energy production. Two isoforms of BIRC5, isoforms 2 and 3, don't seem to play major roles in mitosis, and isoform 3 has significantly reduced anti-apoptotic activity compared to the wild-type form.
BIRC5 is also known as API4, EPR-1.
