A key cofactor of several enzymes implicated in DNA synthesis, repair, and methylation, folate has been shown to be required for normal cell growth and replication and is the basis for cancer chemotherapy using antifolates. γ-Glutamyl hydrolase (GGH) catalyzes the removal of γ-polyglutamate tails of folylpoly-/antifolylpoly-γ-glutamates to facilitate their export out of the cell, thereby maintaining metabolic homeostasis of folates or pharmacological efficacy of antifolates. However, the factors that control or modulate GGH function are not well understood. In this study, we show that intact GGH is not indispensable for the chemosensitivity and growth of acute lymphoblastic leukemia (ALL) cells, whereas GGH lacking N-terminal signal peptide (GGH ) confers the significant drug resistance of ALL cells to the antifolates MTX and RTX. In addition, ALL cells harboring GGH show high susceptibility to the change in folates, and glycosylation is not responsible for these phenotypes elicited by GGH . Mechanistically, the loss of signal peptide enhances intracellular retention of GGH and its lysosomal disposition. Our findings clearly define the in vivo role of GGH in ALL cells and indicate a novel modulation of the GGH function, suggesting new avenues for ALL treatment in future.
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http://dx.doi.org/10.1002/1873-3468.14285 | DOI Listing |
Mol Hortic
January 2025
Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Peptide hormones are defined as small secreted polypeptide-based intercellular communication signal molecules. Such peptide hormones are encoded by nuclear genes, and often go through proteolytic processing of preproproteins and post-translational modifications. Most peptide hormones are secreted out of the cell to interact with membrane-associated receptors in neighboring cells, and subsequently activate signal transductions, leading to changes in gene expression and cellular responses.
View Article and Find Full Text PDFFront Cell Dev Biol
January 2025
Basic Medical Research Centre, Medical School, Nantong University, Nantong, Jiangsu, China.
Background: The normal development of the liver during human embryonic stages is critical for the functionality of the adult liver. Despite this, the essential genes, biological processes, and signal pathways that drive liver development in human embryos remain poorly understood.
Methods: In this study, liver samples were collected from human embryos at progressive developmental stages, ranging from 2-month-old to 7-month-old.
Commun Biol
January 2025
Department of Medicine, UCSD, La Jolla, CA, USA.
Protein kinases play crucial roles in regulating cellular processes, making real-time visualization of their activity essential for understanding signaling dynamics. While genetically encoded fluorescent biosensors have emerged as powerful tools for studying kinase activity, their development for many kinases remains challenging due to the lack of suitable substrate peptides. Here, we present a novel approach for identifying peptide substrates and demonstrate its effectiveness by developing a biosensor for Protein Kinase N (PKN) activity.
View Article and Find Full Text PDFBiochimie
January 2025
School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China. Electronic address:
Microorganisms play a crucial role in the degradation of microcystins (MCs), with most MC-degrading bacteria utilizing the mlr gene cluster (mlrABCD) mechanism. While previous studies have advanced our understanding of the structure, function, and degradation mechanisms of MlrA, MlrB, and MlrC, research on MlrD remains limited. Consequently, the molecular structure and specific catalytic processes of MlrD are still unclear.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel.
ConspectusA key challenge in modern chemistry research is to mimic life-like functions using simple molecular networks and the integration of such networks into the first functional artificial cell. Central to this endeavor is the development of signaling elements that can regulate the cell function in time and space by producing entities of code with specific information to induce downstream activity. Such artificial signaling motifs can emerge in nonequilibrium systems, exhibiting complex dynamic behavior like bistability, multistability, oscillations, and chaos.
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