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Localization of tyrosine‐phosphorylated proteins in cultured mouse dorsal root ganglion neurons
Author(s) -
Shirasu Mikihiro,
Morihara Toru,
Okajima Seiichiro,
Tamai Kazuo,
Mizoguchi Akira,
Ide Chizuka,
Hirasawa Yasusuke
Publication year - 1998
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100160610
Subject(s) - growth cone , filopodia , neurite , immunoelectron microscopy , microbiology and biotechnology , immunogold labelling , tyrosine phosphorylation , biology , dorsal root ganglion , axoplasm , phosphorylation , axon , biochemistry , anatomy , immunology , actin , ultrastructure , immunohistochemistry , dorsum , in vitro
The present study, using confocal laser scanning microscopy and immunoelectron microscopy, examined the intracellular localization of tyrosine‐phosphorylated proteins in cultured mouse dorsal root ganglion neurons with special reference to their growth cones. The growth cone is the specialized structure formed at the growing tip of the axon; characteristically highly motile with filopodia on the surface, it is responsible for the extension and guidance of the neurites to the appropriate targets during nerve regeneration. It has been suggested that protein‐tyrosine phosphorylation plays an important role in the intracellular signal transduction that regulates the extension and motility of growth cones. By fluorescence immunocyto‐chemistry, phosphotyrosine immunoreactivity was found in the growth cones and neurites. Some of the filopodia exhibited strong immunoreactivity at their tips. By immunoelectron microscopy, a large number of immunogold particles (gold particles conjugated to the secondary antibody) were seen to be distributed in the cytoplasm and some were observed on the plasma membrane in the growth cones, whereas in the neurites the density of immunogold particles was the same in the axoplasm as on the plasma membranes. These findings suggest that in the growth cones phosphotyrosines might mainly be involved in intracellular signaling for maintaining their high motility whereas in the neurites they might mostly be associated with the receptor proteins at the plasma membrane for adhesion as well as for growth of neurites. Thus, tyrosine phosphorylation might contribute to different functions for growth cones and neurites.