Survivin: A Keystone in Apoptosis and Cancer Pathways

Abstract

Survivin, also known as baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5), is a versatile protein crucial for inhibiting apoptosis, regulating cell division, and promoting angiogenesis. Encoded by the BIRC5 gene in humans, it is the smallest member of the inhibitor of apoptosis (IAP) gene family in mammalian cells. Survivin's baculoviral IAP repeat (BIR) domain allows it to inhibit apoptosis by directly or indirectly interfering with caspase functions, thus negatively regulating programmed cell death. The survivin protein is highly expressed in most human tumors and fetal tissue but is absent in terminally differentiated cells. Its limited expression in normal differentiated tissues makes it an attractive tumor diagnostic and prognostic marker, and a potential biological target for anticancer therapies.  Regulated by the cell cycle, survivin is particularly expressed during the G2/M phase, associating with the microtubules of the mitotic spindle. Disruption in this association impairs its ability to inhibit apoptosis and may affect mitosis regulation. Understanding survivin's mechanisms could pave the way for new therapeutic strategies in cancer and other diseases.