RT Journal Article
SR Electronic
T1 Nuclear Localization of Overexpressed Glyceraldehyde-3-Phosphate Dehydrogenase in Cultured Cerebellar Neurons Undergoing Apoptosis
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 701
OP 707
DO 10.1124/mol.53.4.701
VO 53
IS 4
A1 Ryoichi Ishitani
A1 Masaharu Tanaka
A1 Katsuyoshi Sunaga
A1 Nobuo Katsube
A1 De-Maw Chuang
YR 1998
UL http://molpharm.aspetjournals.org/content/53/4/701.abstract
AB We recently reported that overexpression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) is directly involved in cytosine arabinonucleoside (ara-C)- and low K+-induced neuronal death of cultured cerebellar granule cells. The former is entirely due to apoptosis, whereas the latter involves both apoptosis and necrosis. We examined the subcellular distribution of the overexpressed GAPDH occurring during apoptosis by using both subcellular fractionation and immunocytochemistry with a monoclonal antibody directed against this overexpressed protein. When immature cerebellar neurons were exposed to ara-C, an overexpression of GAPDH was observed, primarily in the nuclear fraction. In contrast, low K+ exposure of mature cerebellar neurons induced the overexpression of GAPDH not only in the nuclear fraction but also in the mitochondrial fraction. In both paradigms, no significant change of GAPDH levels occurred in the microsomal and cytosolic fractions. Moreover, pretreatment with GAPDH antisense oligonucleotide or classic apoptotic inhibitors clearly suppressed the accumulation of GAPDH protein in these subcellular loci. This discrete nuclear localization of GAPDH during apoptosis was supported further by immunoelectron microscopy. Quantitative assessment of GAPDH immunogold labeling revealed that a ∼5-fold increase in the intensity of gold particles was observed within the nucleus of apoptotic cells. Thus, the current results raise the possibility that neuronal apoptosis may be triggered by GAPDH accumulation in the nucleus, resulting in perturbation of nuclear function and ultimate cell death.