The trkB tyrosine protein kinase gene codes for a second neurogenic receptor that lacks the catalytic kinase domain.
We previously identified two tyrosine protein kinase genes, designated trk and trkB, that code for putative neurogenic cell surface receptors. In this study, we report that the mouse trkB locus codes for at least two classes of receptor-like molecules. These trkB proteins, designated gp145trkB and gp95trkB, have identical extracellular and transmembrane domains, suggesting that they might recognize the same ligand(s). However, only gp145trkB contains a long cytoplasmic region, which includes a catalytic tyrosine protein kinase domain. trkB transcripts coding for this protein were observed in the cerebral cortex and the pyramidal cell layer of the hippocampus. In contrast, transcripts coding for the noncatalytic gp95trkB molecule were found in the ependymal linings of the cerebral ventricles and in the choroid plexus. These results illustrate that a tyrosine protein kinase locus can code for two structurally and functionally distinct cellular receptors.
Klein
R
R
Department of Molecular Biology, Squibb Institute for Medical Research, Princeton, New Jersey 08543-4000.
Conway
D
D
Parada
L F
LF
Barbacid
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002384:Catalysis; D002831:Choroid Plexus / Q000032:analysis; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009928:Organ Specificity / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000502:physiology; D020813:Receptor, trkB; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000235:genetics*; D014158:Transcription, Genetic
D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D017981:Receptors, Neurotransmitter; C064371:Ntrk2 protein, mouse; D011505:Protein-Tyrosine Kinases; D020813:Receptor, trkB