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A function-structure model for NGF-activated TRK
1Department of Pathology and Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
Abstract:
Mechanisms regulating transit of receptor tyrosine kinases (RTKs) from inactive to active states are incompletely described, but require autophosphorylation of tyrosine(s) within a kinase domain 'activation loop'. Here, we employ functional biological assays with mutated TRK receptors to assess a 'switch' model for RTK activation. In this model: (i) ligand binding stimulates activation loop tyrosine phosphorylation; (ii) these phosphotyrosines form specific charge pairs with nearby basic residues; and (iii) the charge pairs stabilize a functionally active conformation in which the activation loop is restrained from blocking access to the kinase catalytic core. Our findings both support this model and identify residues that form specific charge pairs with each of the three TRK activation loop phosphotyrosines.
Insights
This study reveals how receptor tyrosine kinases (RTKs) activate. Specific charge pairs stabilize the active state, enabling cell signaling and providing new targets for drug development.
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Receptor tyrosine kinases (RTKs) are crucial cell signaling proteins.
- Understanding RTK activation mechanisms is vital for disease research.
Purpose of the Study:
- To investigate the 'switch' model of RTK activation.
- To identify specific residues involved in TRK receptor activation.
Main Methods:
- Utilized functional biological assays.
- Employed mutated TRK receptors to test the activation model.
Main Results:
- Provided evidence supporting the 'switch' model for RTK activation.
- Identified specific charge pairs between phosphotyrosines and basic residues in TRK activation loops.
- Demonstrated how these charge pairs stabilize the active kinase conformation.
Conclusions:
- The 'switch' model accurately describes RTK activation.
- Specific residue interactions are key to stabilizing active RTKs.
- Findings offer potential therapeutic targets for modulating RTK activity.