Activation of AMP-activated protein kinase stimulates the nuclear localization of glyceraldehyde 3-phosphate dehydrogenase in human diploid fibroblasts.
In addition to its well-known glycolytic activity, GAPDH displays multiple functions, such as nuclear RNA export, DNA replication and repair, and apoptotic cell death. This functional diversity depends on its intracellular localization. In this study, we explored the signal transduction pathways involved in the nuclear translocation of GAPDH using confocal laser scanning microscopy of immunostained human diploid fibroblasts (HDFs). GAPDH was present mainly in the cytoplasm when cultured with 10% FBS. Serum depletion by culturing cells in a serum-free medium (SFM) led to a gradual accumulation of GAPDH in the nucleus, and this nuclear accumulation was reversed by the re-addition of serum or growth factors, such as PDGF and lysophosphatidic acid. The nuclear export induced by the re-addition of serum or growth factors was prevented by LY 294002 and SH-5, inhibitors of phosphoinositide 3-kinase (PI3K) and Akt/protein kinase B, respectively, suggesting an involvement of the PI3K signaling pathway in the nuclear export of GAPDH. In addition, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), an activator of AMP-activated protein kinase (AMPK), stimulated the nuclear translocation of GAPDH and prevented serum- and growth factor-induced GAPDH export. AMPK inhibition by compound C or AMPK depletion by siRNA treatment partially prevented SFM- and AICAR-induced nuclear translocation of GAPDH. Our data suggest that the nuclear translocation of GAPDH might be regulated by the PI3K signaling pathway acting mainly as a nuclear export signal and the AMPK signaling pathway acting as a nuclear import signal.
Kwon
Hyun Jin
HJ
Department of Biochemistry, Gachon University of Medicine and Science, Incheon 406-799, Korea.
Rhim
Ji Heon
JH
Jang
Ik-Soon
IS
Kim
Go-Eun
GE
Park
Sang Chul
SC
Yeo
Eui-Ju
EJ
D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology*; D016895:Culture Media, Serum-Free; D004171:Diploidy; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000201:enzymology; D028884:Karyopherins / Q000378:metabolism; D008954:Models, Biological; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012265:Ribonucleotides / Q000494:pharmacology; D044967:Serum; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D000097606:Exportin 1 Protein
D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide; D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D036341:Intercellular Signaling Peptides and Proteins; D028884:Karyopherins; D019001:Nitric Oxide Synthase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D018160:Receptors, Cytoplasmic and Nuclear; D012265:Ribonucleotides; D016159:Tumor Suppressor Protein p53; D000097606:Exportin 1 Protein; C031143:AICA ribonucleotide; C038753:leptomycin B