Serine protease FAM111B (FAM111B)

Serine protease FAM111B is an uncharacterized human enzyme predicted to function in DNA repair, cell cycle regulation, and apoptosis. It contains a C-terminal trypsin-like serine protease domain and shows functional homology with FAM111A, a DNA-protein crosslink (DPC) protease. FAM111B degrades p16 (CDKN2A) to promote cell cycle progression, interacts with DNA replication and repair proteins such as PCNA and RFC1, and regulates G2/M transition via cyclin B1 and CDC25C. Dysregulation or mutation of FAM111B can lead to cancer progression and hereditary multisystem fibrosis (POIKTMP), highlighting its critical role in genome stability, DNA repair, and apoptosis. Currently, it is considered a potential therapeutic target in oncology and rare disease, but dedicated drugs and specific inhibitors have not been developed.

Other names

FAM111BCancer-associated nucleoprotein (CANP)Family with sequence similarity 111 member BPOIKTMP (based on disease: hereditary fibrosing poikiloderma with tendon contracture, myopathy, and pulmonary fibrosis)Serine protease FAM111B

Hypothetical: Serine protease inhibitors could inhibit proteolytic activity, potentially restoring proper cell cycle control or blocking cancer progression—no direct clinical evidence. Interference with DNA repair pathways if the protease domain is targeted.