Premium
Exportin 1‐independent nuclear export of GAPDH
Author(s) -
Schmitz HansDirk,
Dutiné Christine,
BereiterHahn Jürgen
Publication year - 2003
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/s1065-6995(03)00096-9
Subject(s) - nuclear export signal , glyceraldehyde 3 phosphate dehydrogenase , chemistry , microbiology and biotechnology , nuclear transport , biochemistry , cell nucleus , biology , messenger rna , gene
Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) is a key enzyme of the glycolytic pathway. Recent studies have demonstrated an additional role in apoptosis: GAPDH is targeted to the nucleus during apoptotic signalling. This nuclear transport has also been observed in serum‐depleted cells, but it is reversible in fibroblasts, in contrast to apoptotic‐induced transport (Eur J Cell Biol 80 (2001) 419). Here, we analyse the serum depletion‐induced transport processes of GAPDH in NIH 3T3 cells. Prolonged serum depletion did not cause cell death, nuclear fragmentation (hoechst staining) or a significant increase in DNA strand‐breaks (comet assay). Using cells expressing green fluorescent protein (GFP)‐tagged GAPDH allowed us to monitor its intracellular localisation by confocal laser scanning microscopy (CLSM). Treatment of cells with the exportin1 inhibitor leptomycin B (LMB) did not influence cytoplasmic localisation of GFP—GAPDH, indicating that nuclear targeting of GAPDH is not constitutive and may be altered via a serum‐dependent regulatory export process. Suprisingly, the export of nuclear GFP—GAPDH after re‐addition of serum to starved cells was not prevented by LMB. Thus, nuclear export of GAPDH upon serum depletion is not mediated by exportin1.