Biology subjects

Pickett, J.

Publications and source records attributed to Pickett, J..

3 recordsLinked to original sources

bioRxiv2026

SGFP-Grid Split GFP Graphene Grids

Affinity graphene grids provide a promising approach for selective protein capture in cryo-EM. Here, we introduce a split-GFP graphene grid platform(SGFP-G), in which graphene-conjugated GFP 1-10 selectively captures GFP11 tagged proteins from low concentration samples or cell lysates. This platform enables rapid assessment of target protein enrichment and particle distribution before vitrification via fluorescence imaging, while the grid design positions captured proteins away from the graphene surface and air-water interface. We also introduce a unique strategy to minimize nonspecific protein adsorption, thereby improving the selective enrichment of target proteins on this grid. Using GFP11-tagged apoferritin, we demonstrate fluorescence guided protein capture and obtain a 2.58 [A] cryoEM reconstruction, establishing SGFP-G as an affinity grid platform for high resolution structural studies with reduced sample requirements.

biochemistry↗

bioRxiv2026

The C. elegans endonuclease NUC-1 acts in engulfing cells to degrade the apoptotic cell DNA

During C. elegans embryonic development, cells undergoing programmed cell death are engulfed by neighboring cells and degraded inside phagosomes. Here we characterize a DNase responsible for the degradation of the chromatin DNA of apoptotic cells. In the past, NUC-1, a homolog of mammalian DNase II, which is only active at acidic pH, was claimed to act in apoptotic cell nuclei for chromatin DNA degradation by some researchers, yet proposed to act in engulfing cells by others. We found that NUC-1 acts exclusively in engulfing cells to degrade apoptotic cell DNA. In nuc-1 mutant embryos, apoptotic cell chromatin DNA remains undegraded. We observed that being engulfed is necessary for the apoptotic chromatin DNA to be degraded. In addition, specific expression of nuc-1 in the engulfing but not dying cells rescues the nuc-1 mutant phenotype. Furthermore, blocking the fusion between lysosomes and a phagosome in engulfing cells blocks apoptotic chromatin DNA degradation. NUC-1 was reported to be a lysosome-located enzyme. We not only confirmed this localization pattern, but also further determined that NUC-1 does not reside in the nuclei of either apoptotic or live cells. This, together with our finding that the nucleus of an apoptotic cell is not acidic, indicates that NUC-1 does not act in the apoptotic cell nucleus; rather, it acts in the engulfing cell phagosomal lumen to degrade apoptotic chromatin DNA. Our work clarified a long-standing controversy regarding the action of NUC-1 and advanced our knowledge of the mechanisms that drive the degradation of specific components of dying cells.

genetics↗

bioRxiv2020

Identification and Optimization of cell active 4-anilino-quin(az)oline Inhibitors for Protein Kinase Novel 3 (PKN3)

The development of a small library of 4-anilinoquinolines led to the identification of 7-iodo-N-(3,4,5-trimethoxyphenyl)quinolin-4-amine 16 as a potent inhibitor of Protein Kinase Novel 3 (PKN3) with an IC50 of 1.3 M in cells. Compound 16 presents a useful potential tool compound to study the biology of PKN3 including links to pancreatic and prostate cancer, along with T-cell acute lymphoblastic leukemia. These compounds may be useful tools to explore the therapeutic potential of PKN3 inhibition in prevention of a broad range of infectious and systemic diseases.

pharmacology and toxicology↗