| 2020 |
Five DYT16 substitution mutations in PACT/PRKRA cause stronger PACT-PACT homodimerization interactions and enhanced PKR activation, leading to dysregulation of the integrated stress response (ISR) and increased apoptosis in patient-derived lymphoblasts. In the absence of stress, PACT and PKR are both bound and inhibited by TRBP; under stress, inhibitory PACT-TRBP and PKR-TRBP interactions dissociate, enabling pro-apoptotic PACT-PACT and PACT-PKR interactions. The flavonoid luteolin disrupts PACT-PKR interactions and rescues the enhanced ER-stress sensitivity. |
Biochemical interaction assays (co-immunoprecipitation), PKR kinase activation assays, eIF2α phosphorylation measurement, apoptosis assays in DYT16 patient-derived lymphoblasts, luteolin rescue experiments |
Neurobiology of disease |
High |
33049316
|
| 2019 |
A frameshift (FS) DYT16 mutation in PACT produces a truncated protein that loses its ability to bind dsRNA and to interact directly with PKR, but retains the ability to interact with PACT itself and with the PKR-inhibitory protein TRBP. When expressed in mammalian cells, the truncated protein aggregates and triggers caspase-dependent apoptosis both in a PKR/PACT-dependent and independent manner. Interaction of the FS mutant with TRBP displaces PACT from the TRBP-PACT complex, resulting in PKR activation and apoptosis. |
In vitro dsRNA-binding assay, co-immunoprecipitation of mutant PACT with PKR and TRBP, fluorescent fusion protein aggregation imaging in mammalian cells, caspase activation assays |
Journal of cellular biochemistry |
High |
31246344
|
| 2024 |
A frameshift mutation in the murine Prkra gene (Prkralear-5J) produces a truncated PACT/RAX protein that retains its ability to interact with PKR but inhibits PKR activation, resulting in reduced eIF2α phosphorylation in the cerebellum and Purkinje neurons. Homozygous mutant mice show abnormal cerebellar development and severe lack of Purkinje neuron dendritic arborization, establishing PACT-mediated PKR activation and eIF2α phosphorylation as required for normal cerebellar development. |
Biochemical co-IP (PACT-PKR interaction), PKR kinase activity assays, eIF2α phosphorylation measurement by western blot, histological analysis of cerebellar development, Purkinje neuron morphology assessment in Prkralear-5J homozygous mice |
Disease models & mechanisms |
High |
39512178
|
| 2025 |
Prkra dimer (via its dimerized dsRNA-binding domain 3) acts as the genuine dsRNA sensor in pluripotent cells (zebrafish embryos and mouse embryonic stem cells) in the absence of an active interferon system. Upon dsRNA binding, activated Prkra dimer sequesters eIF2 complexes away from the translation machinery, inhibiting global protein synthesis in a PKR-independent manner. This mechanism restricts RNA virus replication in zebrafish embryos and compensates for PKR function in differentiated cells. |
dsRNA binding assays, eIF2 complex pull-down/sequestration assays, global translation measurements in zebrafish embryos and mouse ES cells, PKR-independent epistasis experiments, virus replication assays |
Molecular cell |
High |
40280134
|
| 2025 |
N1-methylpseudouridine (m1Ψ) modification of IVT mRNA significantly reduces its binding affinity to the Prkra dimer, thereby preventing Prkra-mediated global translation repression in early zebrafish embryos (pluripotent cells). Unmodified IVT mRNA dsRNA by-products activate Prkra to induce cell necrosis and delay maternal-zygotic transition by reducing global translation efficiency. |
Binding affinity assays between m1Ψ-modified dsRNA and Prkra dimer, global translation efficiency measurements, cell viability and MZT assays in zebrafish embryos with modified/unmodified IVT mRNA |
Nucleic acids research |
High |
41099713
|
| 2011 |
A missense mutation (Serine 130 to Proline) in the second RNA-binding domain of mouse Prkra (RAX/PACT) disrupts dsRNA binding without affecting mRNA expression, but significantly lowers steady-state protein levels in the brain. Homozygous rep mice display defects in ear development, growth, craniofacial development, and ovarian structure, establishing the dsRNA-binding function of Prkra as important for multiple developmental processes. |
Chemical mutagenesis, co-segregation mapping, dsRNA binding assay in vitro, western blot for protein levels, histological phenotype analysis of ear, skull, and ovary in homozygous mice |
PloS one |
High |
22194846
|
| 2022 |
The DYT-PRKRA P222L mutation in PACT augments PACT's ability to induce IFN-β in response to dsRNA via the RIG-I signaling pathway. Basal expression of IFN-β and interferon-stimulated genes (ISGs) is higher in DYT-PRKRA patient cells, and IFN-β and ISGs are induced to higher levels in DYT-PRKRA cells following dsRNA stimulation, demonstrating that P222L enhances PACT's role in type I IFN induction. |
IFN-β reporter assays, qRT-PCR for ISG expression, dsRNA stimulation of DYT-PRKRA patient-derived cells and controls |
Biomolecules |
Medium |
35625640
|
| 2023 |
Luteolin, a plant flavonoid previously identified as an inhibitor of the PACT-PKR interaction by high-throughput screening, markedly disrupts pathological PACT-PKR interactions in DYT-PRKRA cells (carrying enhanced PACT-PKR interaction mutations) and protects these cells against apoptosis. |
PACT-PKR interaction assays (co-IP), apoptosis assays in DYT-PRKRA patient-derived cells treated with luteolin |
Frontiers in pharmacology |
Medium |
36874028
|
| 2011 |
PRKRA (PACT) is a direct target gene of liver-specific miR-122. miR-122 and siRNA-mediated knockdown of PRKRA both facilitate the accumulation of newly synthesized miRNAs (but do not detectably affect endogenous miRNA levels), implicating PRKRA in regulation of miRNA biogenesis, consistent with its known role as a Dicer-interacting protein. |
Affinity purification with biotinylated synthetic miR-122, microarray analysis of pulled-down RNAs, qRT-PCR validation, siRNA knockdown of PRKRA with miRNA quantification |
Nucleic acids research |
Medium |
21937511
|
| 2018 |
PRKRA/PACT promotes chemoresistance in mucinous ovarian cancer (MOC) via its interaction with Dicer, which regulates expression of miR-515-3p. miR-515-3p, in turn, increases sensitivity to oxaliplatin by targeting AXL. PRKRA knockdown combined with oxaliplatin produced significant antitumor effects in orthotopic mouse MOC models. |
siRNA kinome screen, orthotopic mouse model, siRNA knockdown of PRKRA, miR-515-3p expression analysis, AXL targeting validation |
Molecular cancer therapeutics |
Medium |
30305341
|
| 2020 |
PACT/PRKRA interacts with the transcription factor DMRT1 (identified by immunoprecipitation from Xenopus testis followed by MS/MS), and significantly enhances DMRT1-driven transcriptional activity in transfected 293T cells. p53 represses DMRT1 activity and strongly attenuates the enhancement conferred by PACT/PRKRA. |
Co-immunoprecipitation from Xenopus testes with anti-DMRT1 antibody, MS/MS identification of interactors, luciferase reporter assay in 293T cells, in situ hybridization for Pact/Prkra mRNA in tadpole gonads |
Genetics and molecular biology |
Medium |
32251494
|
| 2023 |
PRKRA upregulates the transcription of MMP1 via the NF-κB pathway in pancreatic cancer cells. ChIP and dual-luciferase reporter assays demonstrated that the NF-κB subunit P65 binds to the MMP1 promoter downstream of PRKRA. PRKRA knockout decreased organoid proliferation, while overexpression enhanced xenograft growth and chemoresistance. |
siRNA/CRISPR knockdown and lentiviral overexpression, transcriptome sequencing, ChIP assay for P65 binding to MMP1 promoter, dual-luciferase reporter assay, xenograft mouse model, organoid culture |
Heliyon |
Medium |
37484321
|
| 2025 |
PRKRA knockdown in hepatic cell lines (HepG2, HuH7) increases intracellular total cholesterol and decreases LDL uptake, while PRKRA overexpression has the opposite effect. Mechanistically, reduced PRKRA levels are associated with HMGCS1 upregulation (increased cholesterol biosynthesis) and LDLR downregulation (reduced LDL uptake), as revealed by transcriptome sequencing. |
siRNA knockdown and overexpression in HepG2/HuH7 cells, intracellular cholesterol measurement, Dil-LDL uptake assay, transcriptome sequencing |
Lipids in health and disease |
Low |
40349061
|