Heart Disease The goal of this project is to develop a therapeutic treatment for reducing fibrotic tissue formation following a heart attack. The methodology involves taking the amino acid sequence of a peptide lead compound that targets and inhibits the ROCK-1 kinase and carrying out long timescale molecular dynamics simulations using temperature replica exchange methods in order to sample conformation space as accurately as possible. Subsequent experiments (e.g., circular dichroism) test the predicted peptide conformations. Once validated, the peptide inhibitor conformations are docked against ROCK-1 kinase followed by molecular dynamics simulations of putative complexes. Binding analyses are used as the basis for providing recommendations to an organic chemist collaborator for synthesizing peptidomimetics. Addiction Control This project aims to develop a novel therapeutic strategy for controlling addiction. This pioneering approach entails developing an inhibitor that prevents binding of the PTen protein with the dopamine receptor, and has been validated in an in vivo animal model. The lead compound is also a peptide. The group conducts replica exchange molecular dynamics simulations, docking, and additional simulations of putative complexes. Predictions are provided to an organic chemist for peptidomimetic and derivative synthesis and testing. Structural Mutation Analysis of PTEN and Its Possible Genotype-Phenotype Correlations in Endometriosis and Cancer Loss of function and somatic missense mutations of PTEN have been found in patients with endometriosis, endometrial cancer, and ovarian cancer. Somatic missense mutations linked to these phenotypes were mapped to the signature motif of the catalytic phosphatase domain and C2 domain of PTEN. Among these mutations, moderate phenotypes were associated with endometriosis and endometrial hyperplasia and are distributed throughout both domains. The more severe phenotypes associated with endometrial cancer and ovarian cancer are clustered in the signature motif (H123CKAGKGR130) that forms the P loop at the bottom of the active site pocket. The signature motif contains residues that play a crucial role in loop conformation (H123 and G127) and are essential for catalysis (C124 and R130). One distinct residue within the active site R130 has mutations implicated in both moderate and severe phenotypes. This study explores the structural effects of the identified PTEN mutations on the relationship between genotype and phenotype. Understanding the functional impact missense mutations have on the structure of PTEN is essential to elucidating the molecular mechanism of endometriosis and malignant transformation in the development of novel therapeutics. The phosphatase domain of PTEN may define a region within the active site wherein a small mutation subset possibly correlate with phenotypes. To study the influence of the mutations in greater detail, a combination of structural analysis and molecular dynamics simulations is utilized to characterize atomic interactions and examine the putative effects of the clustered mutations on conformational loop distortions imposed within the active site. The combined approaches employed in this research have the potential to identify the mechanistic role of PTEN associated with endometriosis, endometrial cancer, and ovarian cancer. The results will aid in a better clinical-molecular classification of the resulting phenotypes and allow translation into new diagnostic and therapeutic approaches.
Three- dimensional structure of PTEN (A) Mutations located on phosphatase domain (grey), (B) Mutations located on C2 domain (purple). Severe phenotypes are labeled in red whereas the mild phenotypes are labeled in orange.
Three- dimensional structure of PTEN. (A) Mutations located on phosphatase domain (grey), (B) Mutations located on C2 domain (purple). Severe phenotypes are labeled in red whereas the mild phenotypes are labeled in orange.