Her2 activation mechanism reflects evolutionary preservation of asymmetric ectodomain dimers in the human EGFR family

The receptor tyrosine kinase Her2, an intensely pursued drug target, differs from other members of the EGFR family in that it does not bind EGF-like ligands, relying instead on heterodimerization with other (ligand-bound) EGFR-family receptors for activation. The structural basis for Her2 heterodimerization, however, remains poorly understood. The unexpected recent finding of asymmetric ectodomain dimer structures of Drosophila EGFR (dEGFR) suggests a possible structural basis for Her2 heterodimerization, but all available structures for dimers of human EGFR family ectodomains are symmetric. Here, we report results from long-timescale molecular dynamics simulations indicating that a single ligand is necessary and sufficient to stabilize the ectodomain interface of Her2 heterodimers, which assume an asymmetric conformation similar to that of dEGFR dimers. This structural parallelism suggests a dimerization mechanism that has been conserved in the evolution of the EGFR family from Drosophila to human.

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Predicting the Specificity- Determining Positions of Receptor Tyrosine Kinase Axl

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.658906 ◽

2021 ◽

Vol 8 ◽

Author(s):

Tülay Karakulak ◽

Ahmet Sureyya Rifaioglu ◽

João P. G. L. M. Rodrigues ◽

Ezgi Karaca

Keyword(s):

Molecular Dynamics ◽

Tyrosine Kinase ◽

Molecular Dynamics Simulations ◽

Cancer Progression ◽

Receptor Tyrosine Kinase ◽

Protein Complexes ◽

Immune System Diseases ◽

Specificity Determining Positions ◽

Therapeutic Molecules ◽

Dynamics Simulations

Owing to its clinical significance, modulation of functionally relevant amino acids in protein-protein complexes has attracted a great deal of attention. To this end, many approaches have been proposed to predict the partner-selecting amino acid positions in evolutionarily close complexes. These approaches can be grouped into sequence-based machine learning and structure-based energy-driven methods. In this work, we assessed these methods’ ability to map the specificity-determining positions of Axl, a receptor tyrosine kinase involved in cancer progression and immune system diseases. For sequence-based predictions, we used SDPpred, Multi-RELIEF, and Sequence Harmony. For structure-based predictions, we utilized HADDOCK refinement and molecular dynamics simulations. As a result, we observed that (i) sequence-based methods overpredict partner-selecting residues of Axl and that (ii) combining Multi-RELIEF with HADDOCK-based predictions provides the key Axl residues, covered by the extensive molecular dynamics simulations. Expanding on these results, we propose that a sequence-structure-based approach is necessary to determine specificity-determining positions of Axl, which can guide the development of therapeutic molecules to combat Axl misregulation.

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Use of Molecular Dynamics Simulations in Structure-Based Drug Discovery

Current Pharmaceutical Design ◽

10.2174/1381612825666190903153043 ◽

2019 ◽

Vol 25 (31) ◽

pp. 3339-3349 ◽

Cited By ~ 6

Author(s):

Indrani Bera ◽

Pavan V. Payghan

Keyword(s):

Molecular Dynamics ◽

Drug Discovery ◽

Molecular Dynamics Simulations ◽

Drug Target ◽

Structural Information ◽

Drug Binding ◽

Structure Based Drug Design ◽

Drug Designing ◽

Target Binding ◽

Dynamics Simulations

Background: Traditional drug discovery is a lengthy process which involves a huge amount of resources. Modern-day drug discovers various multidisciplinary approaches amongst which, computational ligand and structure-based drug designing methods contribute significantly. Structure-based drug designing techniques require the knowledge of structural information of drug target and drug-target complexes. Proper understanding of drug-target binding requires the flexibility of both ligand and receptor to be incorporated. Molecular docking refers to the static picture of the drug-target complex(es). Molecular dynamics, on the other hand, introduces flexibility to understand the drug binding process. Objective: The aim of the present study is to provide a systematic review on the usage of molecular dynamics simulations to aid the process of structure-based drug design. Method: This review discussed findings from various research articles and review papers on the use of molecular dynamics in drug discovery. All efforts highlight the practical grounds for which molecular dynamics simulations are used in drug designing program. In summary, various aspects of the use of molecular dynamics simulations that underline the basis of studying drug-target complexes were thoroughly explained. Results: This review is the result of reviewing more than a hundred papers. It summarizes various problems that use molecular dynamics simulations. Conclusion: The findings of this review highlight how molecular dynamics simulations have been successfully implemented to study the structure-function details of specific drug-target complexes. It also identifies the key areas such as stability of drug-target complexes, ligand binding kinetics and identification of allosteric sites which have been elucidated using molecular dynamics simulations.

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