Sae2CtIP

Sae2CtIP is a protein complex involved in DNA double-strand break repair in eukaryotic cells. It is crucial for the homologous recombination pathway, which is a major mechanism for repairing these potentially lethal DNA lesions. The Sae2CtIP complex is composed of two key proteins: Sae2 and CtIP. Sae2, also known as ENSS1, is a nuclease that plays a role in processing the ends of DNA double-strand breaks. CtIP, or RBBP8, is a binding partner that helps recruit other proteins to the break site and contributes to the regulation of DNA end resection.

The formation of the Sae2CtIP complex is a critical early step in DNA repair. Upon sensing a DNA double-strand break, Sae2 is recruited to the break site. CtIP then binds to Sae2, forming the functional complex. This complex initiates DNA end resection, a process where the 5' strands of the broken DNA are degraded, exposing the 3' overhangs. These 3' overhangs are essential for searching for and binding to homologous DNA sequences, which is a prerequisite for accurate repair via homologous recombination. The Sae2CtIP complex's activity is tightly regulated to ensure that resection occurs appropriately and does not lead to uncontrolled DNA degradation. Dysregulation of Sae2CtIP function can result in genomic instability and contribute to diseases such as cancer.