Dentatorubral-pallidoluysian atrophy protein is phosphorylated by c-Jun NH2-terminal kinase.
Dentatorubral-pallidoluysian atrophy (DRPLA) is a dominant-inherited neurodegenerative disease characterized by selective cell loss in particular neuronal pathways. This is caused by expansion of CAG repeats in the coding region of the DRPLA gene, and the extended polyglutamine tract (polyQ) confers a toxic activity. It is valuable to characterize disease gene products for elucidation of the mechanism underlying neuron death at specific anatomical areas of the brain. Here, we define the DRPLA protein as a phosphoprotein, and c-Jun NH(2)-terminal kinase (JNK) is one of the major factors involved in its phosphorylation. Endogenous DRPLA protein was serine-phosphorylated. Phosphorylation was demonstrated in a recombinant JNK activation system in vitro and also in overexpressing cells by transfection after the JNK activation with osmotic pressure. One of the phospho-acceptor sites for JNK appearing in the DRPLA sequence was indeed phosphorylated, which was confirmed by a specific antibody raised against the phosphopeptide. Kinetic studies in the JNK recombinant system showed that expanded polyQ slightly reduced the affinity of JNK to the protein. Thus, the abnormal DRPLA protein seems to be slowly phosphorylated in a certain condition of JNK activation in patients. It may delay a process that is essential in keeping neurons alive.
Okamura-Oho
Yuko
Y
Department of Genetics, National Research Institute for Child Health and Development, 3-35-31 Taishido, Setagaya-ku, Tokyo, 154-8567, Japan.
Miyashita
Toshiyuki
T
Nagao
Kazuaki
K
Shima
Seigo
S
Ogata
Yukie
Y
Katada
Toshiaki
T
Nishina
Hiroshi
H
Yamada
Masao
M
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D045744:Cell Line, Tumor; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D007700:Kinetics; D048670:MAP Kinase Kinase 4; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D009995:Osmosis; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D013997:Time Factors; D014162:Transfection
D009419:Nerve Tissue Proteins; D010455:Peptides; D011994:Recombinant Proteins; C095278:atrophin-1; C097188:polyglutamine; D012694:Serine; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases