Shp-2 specifically regulates several tyrosine-phosphorylated proteins in brain-derived neurotrophic factor signaling in cultured cerebral cortical neurons.
Brain-derived neurotrophic factor (BDNF), a member of the neurotrophins, promotes differentiation and survival and regulates plasticity of various types of neurons. BDNF binds to TrkB, a receptor tyrosine kinase, which results in the activation of a variety of signaling molecules to exert the various functions of BDNF. Shp-2, a Src homology 2 domain-containing cytoplasmic tyrosine phosphatase, is involved in neurotrophin signaling in PC12 cells and cultured cerebral cortical neurons. To examine the roles of Shp-2 in BDNF signaling in cultured rat cerebral cortical neurons, the wild-type and phosphatase-inactive mutant (C/S mutant) forms of Shp-2 were ectopically expressed in cultured neurons using recombinant adenovirus vectors. We found that several proteins tyrosine-phosphorylated in response to BDNF showed enhanced levels of tyrosine phosphorylation in cultured neurons infected with C/S mutant adenovirus in comparison with those infected with the wild-type Shp-2 adenovirus. In addition, in immunoprecipitates with anti-Shp-2 antibody, we also observed at least four proteins that displayed enhanced phosphorylation in response to BDNF in cultured neurons infected with the C/S mutant adenovirus. We found that the Shp-2-binding protein, brain immunoglobulin-like molecule with tyrosine-based activation motifs (BIT), was strongly tyrosine-phosphorylated in response to BDNF in cultured neurons expressing the C/S mutant of Shp-2. In contrast, the level of BDNF-induced phosphorylation of mitogen-activated protein kinase and coprecipitated proteins with anti-Trk and Grb2 antibodies did not show any difference between neurons infected with these two types of Shp-2. Furthermore, the survival effect of BDNF was enhanced by the wild type of Shp-2, although it was not influenced by the C/S mutant of Shp-2. These results indicated that in cultured cerebral cortical neurons Shp-2 is specifically involved in the regulation of several tyrosine-phosphorylated proteins, including BIT, in the BDNF signaling pathway. In addition, the phosphatase Shp-2 may not influence the level of BDNF-induced activation of mitogen-activated protein kinase in cultured cortical neurons. Further, Shp-2 may have potential to positively regulate BDNF-promoting neuronal survival.
Araki
T
T
Division of Protein Biosynthesis, Institute for Protein Research, Osaka University, Suita, Japan.
Yamada
M
M
Ohnishi
H
H
Sano
S
S
Uetsuki
T
T
Hatanaka
H
H
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation; D019208:Brain-Derived Neurotrophic Factor / Q000502:physiology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D051380:GRB2 Adaptor Protein; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation / Q000235:genetics / Q000502:physiology; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020917:Receptor, trkA / Q000378:metabolism; D020813:Receptor, trkB / Q000378:metabolism; D011971:Receptors, Immunologic; D015398:Signal Transduction / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D019208:Brain-Derived Neurotrophic Factor; D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules; D010750:Phosphoproteins; D011506:Proteins; D011971:Receptors, Immunologic; D014443:Tyrosine; D020917:Receptor, trkA; D020813:Receptor, trkB; D020928:Mitogen-Activated Protein Kinases; D010744:Phosphoric Monoester Hydrolases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat