Fbxo34, an F-box protein, is a component of the Skp1-Cullin-F-box (SCF) complexes which are E3 ubiquitin ligases in the ubiquitin proteasome system (UPS). It functions in regulating protein ubiquitination and degradation, and is involved in multiple biological processes, highlighting its importance in maintaining normal cellular functions [2].

In the context of HIV-1 latency, overexpression of FBXO34 can activate latent HIV-1 in multiple latent cell lines. It promotes the ubiquitination and degradation of hnRNP U, a substrate of FBXO34, which abolishes the interaction between hnRNP U and HIV-1 mRNA, thus activating latent HIV-1 [1]. In meiotic oocytes, depletion of FBXO34 leads to failure of oocyte meiotic resumption due to low MPF activity, while overexpression promotes germinal vesicle breakdown but causes spindle assembly checkpoint activation and MI arrest, indicating its role in regulating the G2/M transition and anaphase entry [2]. Additionally, genetic variants of FBXO34 have been associated with the severity of COVID-19 in patients of European ancestry and in a study of hospitalized COVID-19 patients in the UAE [3,4].

In summary, Fbxo34 plays crucial roles in diverse biological processes such as HIV-1 latency regulation, oocyte meiotic maturation, and potentially in the severity of COVID-19. These functions are revealed through studies exploring its overexpression, depletion, and through association with disease-related phenotypes. Understanding Fbxo34's functions may offer insights into the mechanisms of these diseases and potentially lead to new treatment strategies.