This gene encodes one of the proteins of the shelterin, or telosome, complex which protects telomeres by allowing the cell to distinguish between telomeres and regions of DNA damage.

The protein encoded by this gene is a critical part of shelterin; it interacts with the three DNA-binding proteins of the shelterin complex, and it is important for assembly of the complex.

Mutations in this gene cause dyskeratosis congenita (DKC), an inherited bone marrow failure syndrome.