Cyclin F: a component of an E3 ubiquitin ligase complex with roles in neurodegeneration and cancer

Cyclin F, encoded by CCNF, is the substrate recognition component of the Skp1-Cul1-F-box E3 ubiquitin ligase complex, SCF^{cyclin F}. E3 ubiquitin ligases play a key role in ubiquitin-proteasome mediated protein degradation, an essential component of protein homeostatic mechanisms within the cell. By recognising and regulating the availability of several protein substrates, SCF^{cyclin F} plays a role in regulating various cellular processes including replication and repair of DNA and cell cycle checkpoint control. Cyclin F dysfunction has been implicated in various forms of cancer and CCNF mutations were recently linked to familial and sporadic amyotrophic lateral sclerosis and frontotemporal dementia, offering a new lead to understanding the pathogenic mechanisms underlying neurodegeneration. In this review, we evaluate the current literature on the function of cyclin F with an emphasis on its roles in cancer and neurodegeneration.