TrkA and TrkC neurotrophin receptor-like proteins in the lizard gut.
The tyrosine kinase proteins (Trk), encoded by the trk family of proto-oncogenes, mediate, in mammals, the action of neurotrophins, a family of growth factors acting on the development and maintenance of the nervous system. Neurotrophins and their specific receptors, TrkA, TrkB and TrkC, seem to be phylogenetically well preserved but, in reptiles, data regarding the occurrence of Trk-like proteins are very scarce, especially in non-nervous organs. Western blot analysis demonstrated that the lizard gut contains TrkA- and TrkC-like, but not TrkB-like, proteins. Consistently, TrkA- and TrkC-like immunoreactivity were both observed in neurons of the anterior intestine, whereas endocrine cells of the stomach and anterior intestine only displayed TrkA-like immunoreactivity. These results demonstrate for the first time the occurrence of Trk-like proteins in non-neuronal tissues of reptilians and provide further evidence for the evolutionary preservation of the molecular mass and cell distribution of Trk neurotrophin receptor-like proteins in the gut of vertebrates.
Lucini
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C
Università di Napoli Federico II, Dipartimento di Strutture, Funzioni e Tecnologie Biologiche, Via Veterinaria 1, 80137 Naples, Italy. lucini@unina.it
de Girolamo
P
P
Lamanna
C
C
Botte
V
V
Vega
J A
JA
Castaldo
L
L
D000818:Animals; D015153:Blotting, Western; D019858:Enteroendocrine Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007420:Intestine, Large / Q000166:cytology / Q000378:metabolism*; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D008116:Lizards / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D009414:Nerve Growth Factors / Q000378:metabolism; D009474:Neurons / Q000276:immunology / Q000378:metabolism*; D010802:Phylogeny; D011505:Protein-Tyrosine Kinases / Q000276:immunology; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D020917:Receptor, trkA / Q000032:analysis* / Q000276:immunology; D020812:Receptor, trkC / Q000032:analysis* / Q000276:immunology; D017475:Receptors, Nerve Growth Factor / Q000032:analysis / Q000276:immunology; D013270:Stomach / Q000166:cytology; D014018:Tissue Distribution
D009414:Nerve Growth Factors; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA; D020812:Receptor, trkC