Ribosomal stalk proteins RPLP1 and RPLP2 promote biogenesis of flaviviral and cellular multi-pass transmembrane proteins

Abstract

The ribosomal stalk proteins, RPLP1 and RPLP2 (RPLP1/2), which form the ancient ribosomal stalk, were discovered decades ago but their functions remain mysterious. We had previously shown that RPLP1/2 are exquisitely required for replication of dengue virus (DENV) and other mosquito-borne flaviviruses. Here, we show that RPLP1/2 function to relieve ribosome pausing within the DENV envelope coding sequence, leading to enhanced protein stability. We evaluated viral and cellular translation in RPLP1/2-depleted cells using ribosome profiling and found that ribosomes pause in the sequence coding for the N-terminus of the envelope protein, immediately downstream of sequences encoding two adjacent transmembrane domains (TMDs). We also find that RPLP1/2 depletion impacts a ribosome density for a small subset of cellular mRNAs. Importantly, the polarity of ribosomes on mRNAs encoding multiple TMDs was disproportionately affected by RPLP1/2 knockdown, implying a role for RPLP1/2 in multi-pass transmembrane protein biogenesis. These analyses of viral and host RNAs converge to implicate RPLP1/2 as functionally important for ribosomes to elongate through ORFs encoding multiple TMDs. We suggest that the effect of RPLP1/2 at TMD associated pauses is mediated by improving the efficiency of co-translational folding and subsequent protein stability.

Mechanism of action of hepatitis B virus S antigen transport-inhibiting oligonucleotide polymer, STOPS, molecules

“…RPLP2 functions in translating select membrane proteins. 22 GRP78 is a chaperone for membrane-associated proteins and a regulator of the unfolded protein response. 23 SRSF1 and HNRNPA2B1 participate in RNA processing, although they also have roles in other nucleic acid-associated processes.…”

“… 23 SRSF1 and HNRNPA2B1 participate in RNA processing, although they also have roles in other nucleic acid-associated processes. 22 , 23 , 25 All four proteins have previously been described to function in viral infection. 26 , 27 , 28 , 29 , 30 …”

“… 40 For dengue virus, RPLP1/2 decreases the time for translational pausing that could be evolved to coordinate polypeptide synthesis and modification/processing. 22 , 41 A reduction in the amounts of RPLP1/2 could alter the proper timing needed to produce, fold, and post-translationally modify HBsAg. Reduced amounts of GRP78 could result in increased amounts of mis-folded or improperly modified HBsAg that are subject to degradation.…”

Identification and Validation of a Novel RNA-Binding Protein-Related Gene-Based Prognostic Model for Multiple Myeloma

“…RPLP2 also influences multipass transmembrane protein biogenesis, making it important in protein synthesis. Moreover, it is associated with DNA repair, proliferation, apoptosis, and tumorigenesis, and is significantly associated with malignancies such as gynecological tumors, digestive system tumors, and lung adenocarcinoma ( Campos et al, 2020 ). The SNRPB of SMB/B’, the core member of the spliceosome mechanism, promotes cell proliferation and inhibits cell apoptosis.…”

RPLP1, an NS4B-interacting protein, enhances production of CSFV through promoting translation of viral genome

“…RPLP1 is one of the elements of the lateral stalk in the 60S ribosomal subunit [ 20 , 21 ] and usually helps to orchestrate the elongation phase of translation [ 22 , 23 ]. Previous studies suggested that RPLP1 is a pivotal host factor that facilitates viral proteins synthesis of Zika virus (ZIKV), dengue viruses (DENV), and yellow fever virus (YFV) [ 24 , 25 ]. Interestingly, RPLP1 was screened as one of the CSFV NS4B binding partners in our previous yeast two-hybrid (Y2H) system [ 11 ], however, whether RPLP1 is involved in CSFV infection has not been revealed.…”