N-acetyl-D-glucosamine kinase is a component of nuclear speckles and paraspeckles.
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.
Department of Anatomy, Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714, Korea.
Syeda Ridita
SR
Sharif
Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714, Korea.
HyunSook
H
Lee
Department of Anatomy, Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714, Korea.
Md Ariful
MA
Islam
Department of Biochemistry, College of Medicine, Inje University, Busan 614-735, Korea.
Dae-Hyun
DH
Seog
Department of Anatomy, Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714, Korea.|Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714, Korea.
Il Soo
IS
Moon
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D057809:HEK293 Cells; D006624:Hippocampus / Q000166:cytology* / Q000201:enzymology; D006801:Humans; D009474:Neurons / Q000201:enzymology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000378:metabolism; D055517:snRNP Core Proteins / Q000378:metabolism
D016601:RNA-Binding Proteins; D014157:Transcription Factors; D055517:snRNP Core Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); C018716:N-acetylglucosamine kinase
NAGK; dendrite; paraspeckle; proximity ligation assay; snRNPN; speckle