Biology subjects

Chen, P. R.

Publications and source records attributed to Chen, P. R..

2 recordsLinked to original sources

bioRxiv2023

Biochemical and chemical biological approaches to mammalian sleep: roles of calcineurin in site-specific dephosphorylation and sleep regulation

Understanding of sleep mechanisms traditionally rely on electrophysiology and genetics but here we have initiated biochemical and chemical biological studies. Sleep was increased in mouse mutants with an alanine replacing threonine at residue 469 (T469A) of the salt inducible kinase 3 (SIK3). We searched for T469 phosphatases by classic purification with HEK293 cells and by a new photo-crosslinking method with mouse brains. Both led to PPP3CA, a catalytic subunit of calcium/calmodulin activated phosphatase (calcineurin). It dephosphorylated T469 and serine (S) 551 but not T221 in SIK3 in vitro. PPP3CA knockdown increased phosphorylation of T469 and S551 but not T221 in mouse brains. Knockdown of its regulatory subunit PPP3R1 significantly reduced daily sleep by more than 5 hours, exceeding other known mouse mutants. Our results have uncovered in vitro and in vivo evidence for site-specific SIK3 dephosphorylation by calcineurin, demonstrated a physiological role for calcineurin in sleep, and suggested sleep control by calcium dependent dephosphorylation.

neuroscience↗

bioRxiv2023

Bioorthogonal photocatalytic quinone methide decaging for cell-cell interaction labeling

Cell-cell interactions (CCIs) play crucial roles in directing diverse biological processes in multicellular organisms, making the high-sensitivity and selectivity characterization of the diverse CCIs in high demand yet still challenging. We herein introduced a bioorthogonal photocatalytic quinone methide decaging-enabled cell-cell interaction labeling strategy (CAT-Cell) for sensitive and spatiotemporally resolved profiling of multitype CCIs. By adapting an optimized quinone methide probe for interacting cell labeling, we demonstrated the excellent capacity of CAT-Cell for capturing CCIs directed by various receptor-ligand pairs (e.g., CD40-CD40L, TCR-pMHC) and further showed its compatibility with tumor-specific targeting systems. Finally, we used CAT-Cell to detect cytotoxic cells (e.g., antigenspecific T cells, Natural Killer cells) in mouse models containing splenocyte mixtures and tumor samples. By leveraging the bioorthogonal photocatalytic decaging chemistry, CAT-Cell offers as a nongenetic, non-invasive and universal toolbox for profiling diverse CCIs under physiological-relevant settings.

biochemistry↗