Identification and characterization of a novel Pyk2/related adhesion focal tyrosine kinase-associated protein that inhibits alpha-synuclein phosphorylation.
alpha-Synuclein is a presynaptic protein involved in the pathogenesis of several neurodegenerative diseases, such as Parkinson's disease. Pyk2/related adhesion focal tyrosine kinase (RAFTK) tyrosine kinase is an upstream regulator of Src family kinases in the central nervous system that is involved in alpha-synuclein phosphorylation. The present study reports the cloning and characterization of a novel adaptor protein, Pyk2/RAFTK-associated protein (PRAP), that specifically binds to Pyk2/RAFTK and inhibits alpha-synuclein tyrosine phosphorylation. PRAP contains a coiled-coil domain, a pleckstrin homology domain, and a SH3 domain; the SH3 domain binds to the proline-rich domain of Pyk2/RAFTK. PRAP was observed to be present throughout the brain, including substantia nigra dopaminergic neurons, in which it localized to the cytoplasm. PRAP was found to function as a substrate for Src family kinases, such as c-Src or Fyn, but not for Pyk2/RAFTK. Hyperosmotic stress induced phosphorylation of tyrosine 125 of alpha-synuclein via Pyk2/RAFTK, which acted through Src family kinases. Such phosphorylation was inhibited by PRAP expression, suggesting that PRAP negatively regulates alpha-synuclein phosphorylation following cell stress. In conclusion, PRAP functions as a downstream target for Pyk2/RAFTK and plays a role in alpha-synuclein phosphorylation.
Takahashi
Tetsuya
T
Department of Clinical Neuroscience and Therapeutics, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi, Hiroshima, Japan 734-8551.
Yamashita
Hiroshi
H
Nagano
Yoshito
Y
Nakamura
Takeshi
T
Ohmori
Hiromitsu
H
Avraham
Hava
H
Avraham
Shalom
S
Yasuda
Mineo
M
Matsumoto
Masayasu
M
D033942:Adaptor Proteins, Vesicular Transport / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D000595:Amino Acid Sequence; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D051418:Focal Adhesion Kinase 2; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009997:Osmotic Pressure; D010766:Phosphorylation; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051843:Synucleins; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D051844:alpha-Synuclein; D019061:src-Family Kinases / Q000378:metabolism
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; C497604:SNCA protein, human; D051843:Synucleins; D051844:alpha-Synuclein; C116431:src kinase associated phosphoprotein 2; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; D019061:src-Family Kinases