Year-end Sale % OFF 
Abstract
It has been proposed that the high affinity nerve growth factor (NGF) receptor required for NGF response is a complex of two receptor proteins, gp75 and the tyrosine kinase TrkA, but direct biochemical or biophysical evidence has been lacking. We have previously shown using fluorescence recovery after photobleaching that gp75 is highly mobile on NGF-nonresponsive cells, but relatively immobile on NGF-responsive cells. In this report, we show that a physical interaction with TrkA causes gp75 immobilization. We found that gp75 is relatively mobile on TrkA negative nnr5 cells, a PC12 variant which is nonresponsive to NGF. In contrast, on T14 nnr5 cells (which bear a TrkA expression vector) gp75 is relatively immobile. Similarly, using baculoviruses to express gp75 and TrkA on Sf9 insect cells, we found that TrkA immobilizes gp75 molecules. The related receptor, TrkB, caused a more modest immobilization of gp75. Immobilization was found to require intact TrkA kinase and gp75 cytoplasmic domains, paralleling the requirements of high affinity binding of NGF. Analysis of gp75 diffusion coefficients indicates that mutated gp75 and TrkA molecules may form a complex, even in the absence of the ability to bind NGF with high affinity.
Highlights
( known as the low affinity nerve growth factor (NGF) receptor)
Gp75 molecules were labeled with a Fab fragment of a mouse monoclonal antibody (mAb) against gp75 followed by a fluorescein conjugated Fab fragment of a goat anti-mouse IgG
TrkA Immobilization of gp75-To test directly whether an interaction with TrkA causes immobilization of gp75, we compared the diffusion of gp75 on the nonresponsive nnr5 cell line to that of T14 nnr5, a permanent cell line derived from nnr5 which bears a TrkA expression vector and is responsive to NGF
Summary
2133-2138, 1995 Printed in U.S.A. Interaction with TrkA Immobilizes gp in the High Affinity Nerve Growth Factor Receptor Complex*. Analysis of gp diffusion coefficients indicates that mutated gp and TrkA molecules may form a complex, even in the absence of the ability to bind NGF with high affinity. Most membrane proteins are only partially mobile, i.e. a fraction of these molecules are immobilized and do not diffuse In this case, partial recovery is observed. Gp is aggregated and relatively immobile on cell lines which express TrkA and are responsive to NGF [26, 27]. Analysis of diffusion coefficients suggests that mutated forms ofgp and TrkA may still form complexes even in the absence of high affinity binding
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
