Sfpq, also known as splicing factor proline-and glutamine-rich, is a prion-like RNA-binding protein. It is involved in multiple cellular processes such as pre-mRNA splicing, transcriptional regulation, and DNA damage repair. Sfpq is a key component of paraspeckles in the cell nucleus, and its functions are diverse, with implications in various biological pathways and disease-related processes [3,6].

In cancer research, Sfpq has been shown to suppress TGF-β signaling by sequestering Smad4 in its condensates, dampening Smad-dependent transcriptional responses. Sfpq deficiency renders human cells hypersensitive to TGF-β responses, indicating its role in suppressing TGF-β tumor-suppressive activity [1]. In melanoma, knockdown of Sfpq expression decelerates several cancer-associated cell phenotypes, and Sfpq-RNA interactions promote the expression of oncogenic transcripts, suggesting it is an important driver of melanoma [4]. In non-small-cell lung cancer, Sfpq and its isoform show differential expression between cancer and control cells, and could potentially serve as diagnostic and prognostic markers [7].

In the context of viral infections, Sfpq represses Epstein-Barr virus (EBV) lytic reactivation by promoting histone H1 expression, highlighting its role in maintaining EBV latency [5].

In neurodegenerative diseases like Parkinson's disease and dementia with Lewy bodies, nuclear aggregates of NONO/Sfpq and A-to-I-edited RNA are found, which may offer new insights into the inclusion composition and pathophysiology of these diseases [2].

In conclusion, Sfpq is a multifunctional RNA-binding protein with significant roles in cancer, viral latency, and neurodegenerative diseases. Research on Sfpq, including through gene knockout or knockdown models, has provided valuable insights into its functions in these biological processes and disease conditions, contributing to a better understanding of the underlying molecular mechanisms and potentially guiding the development of new therapeutic strategies.