Thy-1 and AvGp50 signal transduction complex in the avian nervous system: c-Fyn and Gαi protein association and activation of signalling pathways
✍ Scribed by Robert C. Henke; Gregory S. Seeto; Peter L. Jeffrey
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 575 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
We have previously reported the isolation of two distinct populations of detergent resistant membrane complexes (DRMC's) from day-old chick brain (Henke et al.: J Neurosci Res 45:617-630, 1996). We now show that the glycosylphosphatidylinositol-anchored proteins Thy-1 and AvGp50 are associated in a signalling complex with c-Fyn, the heterotrimeric G␣i subfamily members G␣i-3, G␣z, and G␣o, ␣ and  tubulin, and a number of other phosphoproteins in immunocomplexes isolated from both populations of DRMC's. Activation of this signalling complex via Thy-1 monoclonal antibody incubation with chick forebrain cells, elicited a decrease in total phosphoprotein profile and tyrosine kinase activity present in DRMC fractions isolated from these cells, while AvGp50 and control antibodies had no effect. Down-regulation of the DRMC phosphoprotein profile was accompanied by an increase in the Thy-1-associated signalling complex, suggesting that activation of this complex initiates the decreases seen in overall DRMC kinase activity. This signalling complex provides the basis for GPI-anchored protein-mediated signal transduction within the unique plasma membrane domains represented by DRMC's.