Biology subjects

Rodgers, D. W.

Publications and source records attributed to Rodgers, D. W..

5 recordsLinked to original sources

bioRxiv2026

The human circular Tau 12->7 RNA is translated in mouse neurons and promotes tau aggregation

In addition to numerous mRNA isoforms, the human microtubule associated protein tau (MAPT) gene generates circular RNAs that are not known to be expressed in rodents. Using adeno associated viruses, we expressed human circular Tau RNA generated from backsplicing of exon 12 to exon 7 (circTau 12->7) in mouse brain. We observed rolling circle translation of circTau 12->7, similar to cultured human HEK293 cells. Despite using a ubiquitously active promoter, circTau 12->7 protein and a control circEGFP protein were only observed in mouse neurons, indicating neuron-specific translation of these circular RNAs. CircTau 12->7 expression resulted in tau aggregates resembling neurofibrillary tangles in mouse brain that included endogenous mouse tau protein. Our data support a model where neuron-specific translation of circTau RNAs induces 'linear', mRNA-translated tau aggregation, which could contribute to tauopathies, including Alzheimer's disease. Thus, targeting circTau RNAs could be a therapeutic approach for Alzheimer's disease.

neuroscience↗

bioRxiv2026

Insulin-degrading enzyme activity is modulated by interaction with pyrroline-5-carboxylate reductase 1

Insulin-degrading enzyme (IDE, insulysin, insulinase) is a peptidase that hydrolyzes a number of bioactive peptides including insulin and the amyloid beta peptide, making it a promising therapeutic target for diabetes and Alzheimers disease. Aspects of its physiological role are still controversial, however. In an attempt to further define IDEs role in cells, we used co-immunoprecipitation experiments to identify potential IDE interacting proteins. The enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) was found associated with IDE in three different cell lines, and the two proteins colocalize in HeLa cells. Purified PYCR1 activates IDE toward small peptide substrates, suggesting a modulatory role for the interaction in vivo. Modeling suggests that the unstructured N-terminal region of PYCR1 inserts into allosteric sites of IDE, contributing to the observed activation. Deleting this sequence alters, but does eliminate, the interaction between PYCR1 and IDE. Since pyrroline-5-carboxylate reductase 1 is a mitochondrial protein, we posit that their interaction could regulate a previously described mitochondrial pool of IDE, which may serve to degrade mitochondrial targeting sequences or amyloid beta peptide that localizes to that organelle.

biochemistry↗

bioRxiv2025

An oligo walk to identify siRNAs against the circular Tau 12->7 RNA

Circular RNAs are associated with numerous diseases and recent evidence shows that they can be translated into proteins after undergoing RNA modification. Circular RNAs differ from their linear mRNA counterparts in their backsplice site, allowing selective targeting using RNA interference, which however limits the options to place the siRNA. We tested all possible siRNAs against the backsplice site of the circTau 12->7 RNA after it was subjected to adenosine to inosine RNA editing, a modification that promotes translation of the circRNA. Most siRNAs reduced the circRNA and protein abundance, which however did not correlate. We identified an siRNA with an IC50 of 750 pmol efficacy on protein expression. This circRNA fulfilled six of the eight criteria for siRNAs targeting mRNAs. Thus, modified circRNAs expressing protein can be targeted with siRNAs, but their optimal sequence needs to be determined empirically.

molecular biology↗

bioRxiv2023

Structure of puromycin-sensitive aminopeptidase and polyglutamine binding

Puromycin-sensitive aminopeptidase (E.C. 3.4.11.14, UniProt P55786), a zinc metallopeptidase belonging to the M1 family, degrades a number of bioactive peptides as well as peptides released from the proteasome, including polyglutamine. We report the crystal structure of PSA at 2.3 A'. Overall, the enzyme adopts a V-shaped architecture with four domains characteristic of the M1 family aminopeptidases, but it is in a less compact conformation compared to most M1 enzymes of known structure. A microtubule binding sequence is present in a C-terminal HEAT repeat domain of the enzyme in a position where it might serve to mediate interaction with tubulin. In the catalytic metallopeptidase domain, an elongated active site groove lined with aromatic and hydrophobic residues and a large S1 subsite may play a role in broad substrate recognition. The structure with bound polyglutamine shows a possible interacting mode of this peptide, which is supported by mutation.

biochemistry↗

bioRxiv2022

S-Acylation Regulates the Membrane Association and Activity of Calpain-5

Calpain-5 (CAPN5) is a member of the calpain family of calcium-activated neutral thiol proteases. CAPN5 is partly membrane associated, despite its lack of a transmembrane domain. Unlike classical calpains, CAPN5 contains a C-terminal C2 domain. C2 domains often have affinity to lipids, mediating membrane association. We recently reported that the C2 domain of CAPN5 was essential for its membrane association and the activation of its autolytic activity. However, despite the removal of the C2 domain by autolysis, the N-terminal fragment of CAPN5 remained membrane associated. S-acylation, also referred to as S-palmitoylation, is a reversible post-translational lipid modification of cysteine residues that promotes membrane association of soluble proteins. In the present study several S-acylated cysteine residues were identified in CAPN5 with the acyl-PEG exchange method. Data reported here demonstrate that CAPN5 is S-acylated on up to three cysteine residues including Cys-4 and Cys-512, and likely Cys-507. The D589N mutation in a potential calcium binding loop within the C2 domain interfered with the S-acylation of CAPN5, likely preventing initial membrane association. Mutating specific cysteine residues of CAPN5 interfered with both its membrane association and the activation of CAPN5 autolysis. Taken together, our results suggest that the S-acylation of CAPN5 is critical for its membrane localization which appears to favor its enzymatic activity.

biochemistry↗