The Biased Ligands NGF and NT-3 Differentially Stabilize Trk-A Dimers

Fozia Ahmed, Elmer Zapata-Mercado, Sanim Rahman, Kalina Hristova

Research output: Contribution to journalArticlepeer-review

Abstract

Trk-A is a receptor tyrosine kinase (RTK) that plays an essential role in the development and functioning of the nervous system. Trk-A is expressed in neurons and signals in response to two ligands, NGF and neurotrophin-3 (NT-3), with very different functional consequences. Thus, NGF and NT-3 are “biased” ligands for Trk-A. Because it has been hypothesized that biased RTK ligands induce differential stabilization of RTK dimers, here, we seek to test this hypothesis for NGF and NT-3. In particular, we use Förster resonance energy transfer (FRET) and fluorescence intensity fluctuation spectroscopy to assess the strength of Trk-A interactions and Trk-A oligomer size in the presence of the two ligands. Although the difference in Trk-A behavior in response to the two ligands has been previously attributed to differences in their binding to Trk-A in the endosomes at low pH, here, we further show differences in the stabilities of the NGF- and NT-3-bound Trk-A dimers in the plasma membrane and at neutral pH. We discuss the biological significance of these new findings and their implications for the design of Trk-A ligands with novel functionalities.

Original languageEnglish (US)
Pages (from-to)55-63
Number of pages9
JournalBiophysical journal
Volume120
Issue number1
DOIs
StatePublished - Jan 5 2021

ASJC Scopus subject areas

  • Biophysics

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