Differential effects of CSF-1R D802V and KIT D816V homologous mutations on receptor tertiary structure and allosteric communication.

Priscila Da Silva Figueiredo Celestino Gomes,Elodie Laine,Eric Solary,Luba Tchertanov,Pedro Geraldo Pascutti,Nicolas Panel,Pratul K Agarwal

doi:10.1371/journal.pone.0097519

Abstract

The colony stimulating factor-1 receptor (CSF-1R) and the stem cell factor receptor KIT, type III receptor tyrosine kinases (RTKs), are important mediators of signal transduction. The normal functions of these receptors can be compromised by gain-of-function mutations associated with different physiopatological impacts. Whereas KIT D816V/H mutation is a well-characterized oncogenic event and principal cause of systemic mastocytosis, the homologous CSF-1R D802V has not been identified in human cancers. The KIT D816V oncogenic mutation triggers resistance to the RTK inhibitor Imatinib used as first line treatment against chronic myeloid leukemia and gastrointestinal tumors. CSF-1R is also sensitive to Imatinib and this sensitivity is altered by mutation D802V. Previous in silico characterization of the D816V mutation in KIT evidenced that the mutation caused a structure reorganization of the juxtamembrane region (JMR) and facilitated its departure from the kinase domain (KD). In this study, we showed that the equivalent CSF-1R D802V mutation does not promote such structural effects on the JMR despite of a reduction on some key H-bonds interactions controlling the JMR binding to the KD. In addition, this mutation disrupts the allosteric communication between two essential regulatory fragments of the receptors, the JMR and the A-loop. Nevertheless, the mutation-induced shift towards an active conformation observed in KIT D816V is not observed in CSF-1R D802V. The distinct impact of equivalent mutation in two homologous RTKs could be associated with the sequence difference between both receptors in the native form, particularly in the JMR region. A local mutation-induced perturbation on the A-loop structure observed in both receptors indicates the stabilization of an inactive non-inhibited form, which Imatinib cannot bind.

Highlights

Receptor tyrosine kinases (RTKs) are cell-surface transmembrane receptors that possess a tightly regulated tyrosine kinase (TK) activity within their cytoplasmic domain [1]
As compared to KIT, whose activating mutations are hallmarks of systemic mastocytosis [5], and gastro-intestinal stromal tumors (GISTs) [6], or to FMSlike tyrosine kinase 3 (FLT3), whose activating mutations are frequently observed in acute myeloid leukemias (AML) [7], activating mutations in colony stimulating factor-1 receptor (CSF-1R) gene have been rarely detected in human tumors [8]
We explore the impact of the equivalent mutation D802V on the structure, dynamics and stability of CSF1R by all-atom molecular dynamics (MD) simulations, principal component analysis (PCA), normal modes analysis (NMA), binding free energy evaluation and inter-residue communication analysis

Summary

Introduction

Receptor tyrosine kinases (RTKs) are cell-surface transmembrane receptors that possess a tightly regulated tyrosine kinase (TK) activity within their cytoplasmic domain [1] They act as sensors for extracellular ligands, the binding of which triggers receptor dimerization and activation of the kinase function, leading to the recruitment, phosphorylation and activation of multiple downstream signaling proteins, which govern the physiology of cells [2]. Based on their overall architecture and kinase domain (KD) sequence, RTKs have been grouped into 20 subfamilies [3]. The receptor could be targeted to prevent osteopenia in neurofibromatosis type-1 [11], whereas the diverse constitutive heterozygous mutations in CSF-1R that are responsible for an autosomal dominant neurological disorder called HDLS (hereditary diffuse leukoencephalopathy with spheroids) are loss of function mutations [12]

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Conclusion