Protein O-GlcNAcylation, dictated by cellular UDP-N-acetylglucosamine (UDP-GlcNAc) levels, plays a crucial role in posttranslational modifications. The enzyme GlcNAc kinase (NAGK, E.C. 2.7.1.59) catalyzes the formation of GlcNAc-6-phosphate, which is a major substrate for the biosynthesis of UDP-GlcNAc. Recent studies have revealed the expression of NAGK in different types of cells especially in neuronal dendrites. Here, by immunocytochemistry (ICC) and immunonucleochemistry (INC) of cultured rat hippocampal neurons, HEK293T and GT1-7 cells, we have showed that NAGK immuno-reactive punctae being present in the nucleoplasm colocalized with small nuclear ribonucleoprotein-associated protein N (snRNPN) and p54NRB, which are speckle and paraspeckle markers, respectively. Furthermore, NAGK IR cluster was also found to be colocalized with GTF2H5 (general transcription factor IIH, polypeptide 5) immuno reactive punctae. In addition, relative localization to the ring of nuclear lamin matrix and to GlcNAc, which is highly enriched in nuclear pore complexes, showed that NAGK surrounds the nucleus at the cytoplasmic face of the nuclear outer membrane. By in situ proximity ligation assay (PLA) we confirmed the colocalization of NAGK with snRNPN in the nucleus and in dendrites, while we also verified the interactions of NAGK with p54NRB, and with GTF2H5 in the nucleus. These associations between NAGK with speckle, paraspeckle and general transcription factor suggest its regulatory roles in gene expression.
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http://dx.doi.org/10.14348/molcells.2015.2242 | DOI Listing |
Biochemistry
January 2025
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Sensing of peptidoglycan fragments is essential for inducing downstream signaling in both mammalian and fungal systems. The hexokinases NagK and Hxk1 are crucial enzymes for the phosphorylation of peptidoglycan molecules in order to activate specific cellular responses; however, biochemical characterization of their enzymatic specificity and efficiency has yet to be investigated in depth. Here a mass spectrometry enzymatic screen was implemented to assess substrate specificity, and an ATP coupled assay provided the quantitative kinetic profiles of these two homologous, eukaryotic enzymes.
View Article and Find Full Text PDFPlant Sci
February 2025
Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia. Electronic address:
In cyanobacteria and most Archaeplastida, Arg regulates its formation via allosteric inhibition of the controlling enzyme, N-acetyl-L-glutamate kinase (NAGK) that requires PII protein to properly sense the feedback inhibitor. Although PII expression has been shown to be reduced in Dunaliella salina compared to other green algae, the potential impact of this protein on DsNAGK activity remains unclear. We here performed coupled enzyme assay and surface plasmon resonance analysis and show that DsNAGK is activated by NAG and inhibited by Arg but is not controlled by DsPII.
View Article and Find Full Text PDFTheriogenology
January 2025
Anhui Provincial Laboratory of Animal Genetic Resources Protection and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, Hefei, Anhui, 230036, China; Anhui Provincial Key Laboratory for Local Livestock and Poultry Genetic Resource Conservation and Bio-Breeding, 130 Changjiang West Road, Hefei, Anhui, 230036, China; Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, Hefei, Anhui, 230036, China. Electronic address:
This study examines the role of N-acetylglucosamine kinase (NAGK) in initiating puberty in female mice. We employed real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence to measure NAGK expression in the hypothalamic-pituitary-ovarian axis across various developmental stages: infant, prepuberty, puberty, and adult. We further investigated the impact of Nagk gene knockdown on puberty in female mice.
View Article and Find Full Text PDFSci Rep
October 2024
Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, 611-0011, Japan.
Clostridium perfringens, an opportunistic pathogen, produces mu-toxin hyaluronidases including endo-β-N-acetylglucosaminidases (Nags) as a virulence invasion factor. To clarify an intrinsic factor for degradation of host extracellular hyaluronan, we focused on hyaluronate lyase (HysA), distinct from endo-β-N-acetylglucosaminidases. C.
View Article and Find Full Text PDFAm J Cancer Res
September 2024
PhD Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University-Shuang Ho Campus New Taipei 235, Taiwan.
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