Proteases are critical enzymes in cellular processes which regulate intricate events like cellular proliferation, differentiation and apoptosis. This review highlights the multifaceted roles of the serine proteases FAM111A and FAM111B, exploring their impact on cellular functions and diseases. FAM111A is implicated in DNA replication and replication fork protection, thereby maintaining genome integrity. Additionally, FAM111A functions as an antiviral factor against DNA and RNA viruses. Apart from being involved in DNA repair, FAM111B, a paralog of FAM111A, participates in cell cycle regulation and apoptosis. It influences the apoptotic pathway by upregulating anti-apoptotic proteins and modulating cell cycle-related proteins. Furthermore, FAM111B's association with nucleoporins suggests its involvement in nucleo-cytoplasmic trafficking and plays a role in maintaining normal telomere length. FAM111A and FAM111B also exhibit some interconnectedness and functional similarity despite their distinct roles in cellular processes and associated diseases resulting from their dysfunction. FAM111A and FAM111B dysregulation are linked to genetic disorders: Kenny-Caffey Syndrome type 2 and Gracile Bone Dysplasia for FAM111A and POIKTMP, respectively, and cancers. Therefore, the dysregulation of these proteases in diseases emphasizes their potential as diagnostic markers and therapeutic targets. Future research is essential to unravel the intricate mechanisms governing FAM111A and FAM111B and explore their therapeutic implications comprehensively.
Keywords: FAM111A; FAM111B; genetic fibrosing disorders; proteases.