Biology subjects

Biedenkopf, N.

Publications and source records attributed to Biedenkopf, N..

4 recordsLinked to original sources

bioRxiv2026

HNRNPM promotes protein synthesis via an interaction with stem-loop 5 in the SARS-CoV-2 5'-UTR

The 5'-untranslated region (5'-UTR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly structured and comprises five conserved stem-loops that serve as cis-acting regulatory elements. During infection, host proteins are recruited to these elements and regulate multiple steps during the viral life cycle. Stem-loop 5 (SL5) is highly conserved among different alpha- and betacoronaviruses and includes the start codon of non-structural protein 1 (nsp1). However, the function of SL5 in viral replication and its interacting proteins remain to be determined. Here, we identified heterogeneous nuclear ribonucleoprotein M (HNRNPM) as a host protein functionally interacting with SL5. HNRNPM translocates into the cytoplasm during SARS-CoV-2 infection and promotes protein synthesis from the viral 5'-UTR. Mutations in the lower stem of SL5 impair HNRNPM binding and reduce protein synthesis. Notably, the interaction between HNRNPM and SL5 is conserved among different alpha- and betacoronaviruses. Our findings indicate that HNRNPM is an important host factor that regulates viral translation to promote SARS-CoV-2 replication.

biochemistry↗

bioRxiv2026

Laudanosine restricts Ebola virus entry by targeting TPC2-dependent endolysosomal trafficking

Late endosome-dependent viruses, including filo- and arenaviruses, rely on host endolysosomal trafficking for productive infection. Here, we used a dual-colour Vesicular stomatitis virus (VSV) based pseudoparticle screen of CytoSorb-derived fractions to identify inhibitors of the Zaire Ebolavirus glycoprotein (GP)-mediated entry. Iterative chromatographic purification and mass spectrometry identified Laudanosine, a degradation product of the clinically used neuromuscular blocker Atracurium, as the antiviral compound. Laudanosine specifically inhibited entry mediated by Ebola, Marburg, Lymphocytic choriomeningitis and Lassa virus glycoproteins without affecting VSV-G-dependent entry. Importantly, Laudanosine inhibited authentic Ebola virus infection without detectable cytotoxicity in cell culture and embryonic zebrafish. Molecular dynamics simulations suggest stable association of Laudanosine with the allosteric inhibitory pocket of the lysosomal two-pore channel (TPC2). Consistently, Laudanosine impairs autophagic flux and disrupts endolysosomal trafficking. Together, our findings identify Laudanosine as a previously unrecognised inhibitor of TPC2-dependent entry of highly lethal viral pathogens.

microbiology↗

bioRxiv2020

Non-canonical proline-tyrosine interactions with multiple host proteins regulate Ebola virus infection

The Ebola virus VP30 protein interacts with the viral nucleoprotein and with host protein RBBP6 via PPxPxY motifs. In these interactions the largely alpha-helical carboxy-terminal domain of the EBOV VP30 engages with the motif such that the prolines adopt non-canonical orientations, as compared to other proline-rich motifs. Affinity tag-purification mass spectrometry identified additional PPxPxY-containing host proteins, including hnRNP L, hnRNPUL1 and PEG10, as VP30 interactors. Of these, hnRNP L and PEG10, like RBBP6, inhibit viral RNA synthesis and EBOV replication, whereas hnRNPUL1 enhances. Further, double knockdown studies support additive effects of RBBP6 and hnRNP L. Binding studies demonstrate variable capacity of PPxPxY motifs to bind VP30 and the extended motif PxPPPPxY is demonstrated to confer optimal binding and to inhibit RNA synthesis, with the fifth proline and the tyrosine being most critical. Competition binding and hydrogen-deuterium exchange studies demonstrate that each protein binds a similar interface on VP30 and impacts VP30 phosphorylation. VP30 therefore represents a novel proline recognition domain that allows multiple host proteins to target a single viral protein-protein interface to modulate viral transcription.

microbiology↗

bioRxiv2019

Serine-arginine protein kinase 1 regulates Ebola virus transcription

Ebola virus (EBOV) causes a severe and often fatal disease for which no approved vaccines or antivirals are currently available. EBOV transcription requires the sequential phosphorylation and dephosphorylation of the viral transcription factor VP30. While dephosphorylation is carried out by phosphatases PP2A and PP1, the VP30-specific kinase is unknown. Here, we report that serine-arginine protein kinase 1 and 2 (SRPK1 and SRPK2) phosphorylate serine-29 of VP30, which is located in an N-terminal R26xxS29 motif. Interaction with VP30 via the R26xxS29 motif recruits SRPK1 into EBOV-induced inclusion bodies, the sites of viral RNA synthesis and an inhibitor of SRPK1/SRPK2 downregulates primary viral transcription. When the SRPK1 recognition motif of VP30 was mutated in a recombinant EBOV, virus replication was severely impaired. It is presumed that the interplay between SRPK1 and PP2A in the EBOV inclusions provides a comprehensive regulatory circuit to ensure the activity of VP30 in EBOV transcription.

microbiology↗