[6][7] HCF1 is a member of the highly conserved host cell factor family and encodes a protein with five Kelch repeats, a fibronectin-like motif, and six HCF repeats, each of which contains a highly specific cleavage signal.

The final form of this protein consists of noncovalently bound N- and C-terminal chains which interact through electrostatic forces.

HCF1 is involved in control of the cell cycle as well as having regulatory roles in a multitude of processes related to transcription.

Additionally, work in model organisms point to HCF1 as being a putative longevity determinant.

[7] Mutations in this gene have been linked to disorders of the cobalamine metabolism.