Biology subjects

Paige, A. S.

Publications and source records attributed to Paige, A. S..

4 recordsLinked to original sources

bioRxiv2025

Nanobody-Driven Stabilization Synergistically Rescues F508del-CFTR and Reveals an Alternative Active State of the Channel

Defects in protein trafficking underlie many genetic diseases, including cystic fibrosis (CF), where the predominant F508del mutation destabilizes the cystic fibrosis transmembrane conductance regulator (CFTR) channel, leading to its degradation. To provide a protein-specific chaperone, we used lipid nanoparticles to deliver mRNA encoding T2a, a nanobody that thermally stabilizes CFTR via high-affinity binding to nucleotide-binding domain 1 (NBD1). When combined with clinically-approved correctors, T2a considerably improved F508del-CFTR maturation, plasma membrane expression, and channel activity. Single-channel recordings revealed that nanobody binding sustained channel activity by promoting both full open and sub-conductance gating states and protecting F508del-CFTR against thermal deactivation. Because T2a binding to NBD1 prevents the ATP-dependent NBD1-NBD2 association that drives canonical channel opening, the observation of channel activity in the presence of the nanobody suggested adoption of a novel open-channel CFTR structure. This inference was confirmed by cryo-EM analyses of CFTR in the presence of T2a, which revealed a novel open-channel conformation in which NBD1 binds to an alternative site on CFTR incompatible with NBD dimerization. Our findings establish a new paradigm to correct protein trafficking by stabilizing misfolded domains with targeted nanobodies and demonstrate a broadly applicable framework to treat CF and related protein misfolding diseases.

biochemistry↗

bioRxiv2023

Sex peptide receptor is not required for refractoriness to remating or induction of egg laying in Aedes aegypti

Across diverse insect taxa, the behavior and physiology of females dramatically changes after mating - processes largely triggered by the transfer of seminal proteins from their mates. In the vinegar fly Drosophila melanogaster, the seminal protein sex peptide (SP) decreases the likelihood of female flies remating and causes additional behavioral and physiological changes that promote fertility including increasing egg production. Although SP is only found in the Drosophila genus, its receptor, sex peptide receptor (SPR), is the widely-conserved myoinhibitory peptide (MIP) receptor. To test the functional role of SPR in mediating post-mating responses in a non-Drosophila dipteran, we generated two independent Spr-knockout alleles in the yellow fever mosquito Aedes aegypti. Although SPR is needed for post-mating responses in Drosophila and the cotton bollworm Helicoverpa armigera, Spr mutant Ae. aegypti show completely normal post-mating decreases in remating propensity and increases in egg laying. In addition, injection of synthetic SP or accessory gland homogenate from D. melanogaster into virgin female mosquitoes did not elicit these post-mating responses. Our results indicate that Spr is not required for these canonical post-mating responses in Ae. aegypti, indicating that unknown signaling pathways are likely responsible for these behavioral switches in this disease vector.

genetics↗

bioRxiv2023

In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome

U7 snRNP is a multi-subunit endonuclease required for 3 end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50 and pICln known to methylate arginines in the C-terminal regions of the Sm proteins B, D1 and D3 during the spliceosomal Sm ring assembly. Both biochemical and Cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the N-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an N-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.

biochemistry↗

bioRxiv2019

Linking nutrient stoichiometry to Zika virus transmission in a mosquito

Food quality and quantity serve as the basis for cycling of key chemical elements in trophic interactions, yet the role of nutrient stoichiometry in shaping host-parasite interactions is under appreciated. Most of the emergent mosquito-borne viruses affecting human health are transmitted by mosquitoes that inhabit container systems during their immature stages, where allochthonous input of detritus serves as the basal nutrients. Quantity and type of detritus (animal and plant) were manipulated in microcosms containing newly hatched Aedes aegypti mosquito larvae. Adult mosquitoes derived from these microcosms were allowed to ingest Zika virus infected blood and then tested for disseminated infection, transmission, and total nutrients (percent carbon, percent nitrogen, ratio of carbon to nitrogen). Treatments lacking high quality animal (insect) detritus significantly delayed development. Survivorship to adulthood was closely associated with the amount of insect detritus present. Insect detritus was positively correlated with percent nitrogen, which affected Zika virus infection. Disseminated infection and transmission decreased with increasing insect detritus and percent nitrogen. We provide the first definitive evidence linking nutrient stoichiometry to arbovirus infection and transmission in a mosquito using a model system of invasive Ae. aegypti and emergent Zika virus.

ecology↗