{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent structural and biochemical studies have shed light on the mechanism of phosphoryl transfer in cAMP‐dependent protein kinase (PKA). High‐resolution crystallographic analyses revealed a transition‐state mimic involving ADP, magnesium ions, aluminum fluoride, and substrate peptides that define the in‐line phosphoryl transfer mechanism of the PKA catalytic subunit (1:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In complementary studies, ablation of specific neural‐expressed PKA Cβ isoforms in mice demonstrated that while total PKA activity may be partly maintained through compensatory mechanisms, loss of these isoforms can subtly affect memory and neuronal signaling (3:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " Likewise, analyses of PKA catalytic splice variants—including the characterization of Cα and Cβ isoforms in human, bovine, and murine tissues—underscore the complexity of PKA regulation at the molecular level (9:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nAt the cellular and organismal levels, PKA-mediated signaling cascades are pivotal for diverse physiological responses. Multiomic investigations in kidney epithelial cells revealed that PKA is a key mediator of vasopressin-induced water channel (AQP2) exocytosis and gene transcription, processes that involve intricate cross-talk with MAP kinase cascades (2:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": " In renal cells, distinct signaling pathways were uncovered whereby the protein kinase C (PKC) pathway regulates TRPV4 channel activity, while a concomitant activation of PKA influences channel trafficking to the apical membrane (4:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": " Furthermore, cilia-based Hedgehog signal transduction involves modulation of Gli2/Gli3 phosphorylation via PKA, highlighting the spatial regulation of kinase activity (5:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Additional studies in pancreatic beta-cells have shown that PKA isoform redistribution underlies glucose-dependent insulin secretion (6:"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": ", while studies of the Carney complex and colon cancer models emphasize that dysregulated PKA activity can drive tumorigenesis (7:"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "; 8:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurther insights into tissue-specific PKA functions come from investigations into immune cell activity and alternative splicing of PKA catalytic subunits. Detailed characterization of a larger PKA Cβ splice variant enriched in T, B, and natural killer (NK) cells revealed that loss of this variant leads to decreased cAMP-induced catalytic activity and heightened systemic inflammatory responses, as evidenced by increased sensitivity to arthritis and altered cytokine profiles (10:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": " In addition, the identification of novel murine Cβ splice variants adds another layer to the regulation of PKA’s diverse cellular functions (11:."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "11"}]}, {"type": "t", "text": " Although none of these studies explicitly mention LINC01723, the extensive analyses of PKA catalytic and regulatory mechanisms across various models suggest that long noncoding RNAs such as LINC01723 could represent an unexplored regulatory layer. Given the emerging role of lncRNAs in modulating gene expression, protein–protein interactions, and signal transduction, one may speculate that LINC01723 might influence PKA-mediated pathways—possibly by acting as a scaffold, decoy, or epigenetic regulator—to fine-tune cellular responses. Future studies are warranted to delineate any direct role for LINC01723 within these PKA-centered signaling networks."}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": " Madhusudan, Pearl Akamine, Nguyen-Huu Xuong, et al. 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