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Tissue-specific alternative splicing generates two isoforms of the trkA receptor
P A Barker1, C Lomen-Hoerth, E M Gensch
1Department of Neurobiology, Stanford University, California 94305-5401.
The Journal of Biological Chemistry
|July 15, 1993
Summary
Alternative splicing creates two nerve growth factor receptor (trkA) isoforms. These isoforms, differing by a 6-amino acid insert, show distinct tissue expression patterns but similar signaling functions.
Area of Science:
- Molecular biology
- Neuroscience
- Cell signaling
Background:
- The trkA receptor is crucial for signal transduction of nerve growth factor (NGF).
- Alternative splicing is a known mechanism for generating protein diversity.
Purpose of the Study:
- To investigate the existence and functional implications of different trkA receptor isoforms.
- To determine the tissue-specific expression of trkA isoforms in rats and humans.
Main Methods:
- Analysis of trkA gene expression and protein products in rat and human tissues.
- Functional assays in fibroblasts to assess ligand binding and signal transduction.
- Comparison of trkA isoforms based on their amino acid sequences and structural features.
Main Results:
- Two distinct trkA isoforms, trkAI and trkAII, were identified due to alternative splicing.
- The isoforms differ by a 6-amino acid insertion in the extracellular domain, located at a breakpoint common in trkA oncogenes.
- Both isoforms bind NGF and transduce signals similarly in fibroblasts.
- trkAI is predominantly expressed in non-neuronal tissues, while trkAII is the main isoform in neuronal tissues.
Conclusions:
- Alternative splicing generates functionally similar yet differentially expressed trkA receptor isoforms.
- The differential expression of trkA isoforms may play a role in neuronal development and function.
- Understanding trkA isoforms is important for research into neurotrophic factor signaling and related oncogenic pathways.