Biology subjects

Scinicariello, S.

Publications and source records attributed to Scinicariello, S..

4 recordsLinked to original sources

bioRxiv2024

ERH regulates type II interferon immune signaling through post-transcriptional regulation of JAK2 mRNA

Type II interferon (IFN{gamma}) signaling is essential for innate immunity and critical for effective immunological checkpoint blockade in cancer immunotherapy. Genetic screen identification of post-transcriptional regulators of this pathway has been challenging since such factors are often essential for cell viability. Here, we utilize our inducible CRISPR/Cas9 approach to screen for key post-transcriptional regulators of IFN{gamma} signaling, and in this way identify ERH and the ERH-associated splicing and RNA export factors MAGOH, SRSF1, and ALYREF. Loss of these factors impairs post-transcriptional mRNA maturation of JAK2, a crucial kinase for IFN{gamma} signaling, resulting in abrogated JAK2 protein levels and diminished IFN{gamma} signaling. Further analysis highlights a critical role for ERH in preventing intron retention in AU-rich regions in specific transcripts, such as JAK2. This regulation is markedly different from previously described retention of GC-rich introns. Overall, these findings reveal that post-transcriptional JAK2 processing is a critical rate-limiting step for the IFN{gamma}-driven innate immune response.

cell biology↗

bioRxiv2024

Multiple ubiquitin ligases protect human genome integrity by targeting cancer-associated APOBEC3 deaminases for degradation.

HighlightsO_LIRNA-free APOBEC3 (A3) can enter the nucleus, leading to genomic mutations. C_LIO_LIThree E3 ligases specifically bind the RNA-binding domain of nuclear A3s. C_LIO_LICancer-associated A3B and A3H-I are thereby targeted for proteasomal degradation. C_LIO_LIThese E3 ligases thus act as genome guardians by limiting A3-mediated mutagenesis. C_LI APOBEC family members play crucial roles in antiviral restriction. However, certain APOBEC3 (A3) proteins drive harmful hypermutation in humans, contributing to cancer. The cancer-associated A3 proteins are capable of transiting from the cytosol to the nucleus, where they can cause genome mutations. Here, we uncover a specific set of cellular pathways that protect genomic DNA from the major cancer-associated A3 proteins. Through genetic and proteomic screening we identify UBR4, UBR5, and HUWE1 as key ubiquitin E3 ligases marking cancer-associated A3B and A3H-I for degradation, thereby limiting A3-driven hypermutation. Mechanistically, UBR5 and HUWE1 recognize unoccupied A3 RNA-binding domains, thus promoting proteasomal degradation of APOBEC3 protein that is not engaged in its antiviral cellular function. Depletion or mutation of the E3 ligases in cells and human cancer samples increases A3-driven genome mutagenesis. Our findings reveal that UBR4, UBR5, and HUWE1 are crucial factors in a ubiquitination cascade that maintains human genome stability.

cell biology↗

bioRxiv2023

Pre-mRNA fate decision safeguards the fidelity of the inflammatory response

The fidelity of immune responses depends on a timely controlled and selective mRNA degradation that is largely driven by RNA-binding proteins (RBPs)[1, 2]. It remains unclear whether the selection of an individual mRNA molecule for degradation is governed by stochastic or directed processes. Here, we show that tristetraprolin (TTP, also known as ZFP36), an essential anti-inflammatory RBP[3], destabilizes target mRNAs via a hierarchical molecular assembly. The formation of the assembly strictly relies on the interaction of TTP with RNA. The TTP homolog ZFP36L1 exhibits similar requirements, indicating a broader relevance of this regulatory program. Unexpectedly, the assembly of the cytoplasmic mRNA-destabilization complex is licensed in the nucleus by TTP binding to pre-mRNA, while mature cytoplasmic mRNA does not constitute a de novo TTP target. Hence, the fate of an inflammation-induced mRNA is decided concomitantly with its synthesis. This decision mechanism prevents the translation of superfluous and potentially harmful inflammation mediators, ensuring an efficient cessation of the immune response, irrespective of transcriptional activity.

molecular biology↗

bioRxiv2022

HUWE1 controls tristetraprolin proteasomal degradation by regulating its phosphorylation

Tristetraprolin (TTP) is a critical negative immune regulator. It binds AU-rich elements in the untranslated-regions of many mRNAs encoding pro-inflammatory mediators, thereby accelerating their decay. A key but poorly understood mechanism of TTP regulation is its timely proteolytic removal: TTP is degraded by the proteasome through yet unidentified phosphorylation-controlled drivers. In this study, we set out to identify factors controlling TTP stability. Cellular assays showed that TTP is strongly lysine-ubiquitinated, which is required for its turnover. A genetic screen identified the ubiquitin E3 ligase HUWE1 as a strong regulator of TTP proteasomal degradation, which we found to control TTP stability indirectly by regulating its phosphorylation. Pharmacological assessment of multiple kinases revealed that HUWE1-regulated TTP phosphorylation and stability was independent of the previously characterized effects of MAPK-mediated S52/S178 phosphorylation. HUWE1 function was dependent on phosphatase and E3 ligase binding sites identified in the TTP C-terminus. Our findings indicate that while phosphorylation of S52/S178 is critical for TTP stabilization at earlier times after pro-inflammatory stimulation, phosphorylation of the TTP C-terminus controls its stability at later stages.

cell biology↗