Participation of a fusogenic protein, glyceraldehyde-3-phosphate dehydrogenase, in nuclear membrane assembly.
We found an autoimmune serum, K199, that strongly suppresses nuclear membrane assembly in a cell-free system involving a Xenopus egg extract. Four different antibodies that suppress nuclear assembly were affinity-purified from the serum using Xenopus egg cytosol proteins. Three proteins recognized by these antibodies were identified by partial amino acid sequencing to be glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-1,6-bisphosphate aldolase, and the regulator of chromatin condensation 1. GAPDH is known to be a fusogenic protein. To verify the participation of GAPDH in nuclear membrane fusion, authentic antibodies against human and rat GAPDH were applied, and strong suppression of nuclear assembly at the nuclear membrane fusion step was observed. The nuclear assembly activity suppressed by antibodies was recovered on the addition of purified chicken GAPDH. A peptide with the sequence of amino acid residues 70-94 of GAPDH, which inhibits GAPDH-induced phospholipid vesicle fusion, inhibited nuclear assembly at the nuclear membrane fusion step. We propose that GAPDH plays a crucial role in the membrane fusion step in nuclear assembly in a Xenopus egg extract cell-free system.
Nakagawa
Tomoaki
T
Course of Functional Biology, Graduate School of Science and Technology, Niigata University, Igarashi-2, Japan.
Hirano
Yasuhiro
Y
Inomata
Akira
A
Yokota
Sadaki
S
Miyachi
Kiyomitsu
K
Kaneda
Mizuho
M
Umeda
Masato
M
Furukawa
Kazuhiro
K
Omata
Saburo
S
Horigome
Tsuneyoshi
T
D000595:Amino Acid Sequence; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism* / Q000502:physiology; D007106:Immune Sera; D008561:Membrane Fusion / Q000502:physiology; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000201:enzymology*; D014981:Xenopus
D007106:Immune Sera; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases