STAG2/SA2 [J12]

The cohesin complex consists of a heterodimer between SMC1 and SMC3, as well as a linker protein RAD21 and STAG proteins (STAG1, 2, or 3). These proteins form a ring-like structure that mediates the cohesion of two sister chromatids after DNA replication in S phase. STAG2, also known as SA2 (stromal antigen 2), is a 1231 amino acid component of the cohesion complex that interacts directly with Rad21. RAD21 and STAG2 are phosphorylated by Polo-like kinase (PLK) during prophase, which leads to the dissociation of cohesin complexes from the chromosome arms. Localized to the nucleus, STAG2 associates with chromatin and, upon phosphorylation by Plk, dissociates from chromatin to allow proper chromosome separation during anaphase. STAG2 is able to enhance the activity of tumor necrosis factor alpha (TNFα) and may be a putative transcriptional regulator.