| Popis: |
Apoptosis is a form of controlled cell death that occurs as a normal part of an organism’s growth and development. Apoptosis is often initiated as a result of external or internal stresses that the cell cannot overcome and thus becomes committed to die. Defects in a cell’s apoptosis machinery can result in uncontrolled cell division, leading to cancer or auto-immune disorders. Our work focuses on studying the interactions between pro- apoptotic (pro-death) and anti-apoptotic (pro-survival) proteins involved in the intrinsic apoptosis pathway. Specifically, we are interested in developing molecules that inhibit anti-apoptotic BCL2 family proteins in order to facilitate cell death in diseases that result from dysregulated apoptosis mechanisms.The primary area of my research involves studying the interaction between the pro-apoptotic protein Bax and the anti-apoptotic protein Bcl-2. Bax interacts with Bcl-2 via its helical BH3 domain, causing Bax to remain inactivated. In times of cellular stress, activated Bax becomes unbound from Bcl-2 and initiates the release of cytochrome c from mitochondria, leading to cell death via apoptosis. Our lab recently developed a series of molecules based on the small protein scyllatoxin (ScTx) as inhibitors of the Bax:Bcl-2 interaction. Notably, synthetic ScTx can be modified to target anti-apoptotic Bcl-2 proteins by replacing natural amino acids within the ScTx helix with Bax BH3 residues that are important for Bcl-2 recognition. 4 My studies have included establishing screens to co-crystalize Bcl-2 or Bcl-2(G145A) (a mutant of Bcl-2 that resists interactions with other BCL2 BH3 domains) with ScTx-based BH3 domain mimetics or truncated Bax BH3 domains. In addition, we have conducted isothermal titration calorimetry (ITC) studies with ScTx-Bax structural variants in complex with Bcl-2. These studies have helped to elucidate structural requirements and energetic properties for targeting anti-apoptotic Bcl-2 with ScTx-Bax BH3 domain mimetics in vitro. Such information may facilitate the development of next- generation inhibitors of BH3:Bcl-2 interactions that can be used to treat Bcl-2-mediated diseases.Another area of research our lab focuses on is inhibiting human growth hormone (hGH) from binding to human growth hormone receptor (hGHR) using small peptide- based antagonists. Such peptides were used to inhibit hGH-mediated STAT5 phosphorylation in cells. To facilitate this research, I have developed a series of photoaffinity labelled (PAL) peptides that can be used to map the interaction between such peptide-based antagonists and the hGHR. These studies may provide understanding of what residues of hGH interact with the hGHR and will be critical for developing next- generation therapeutics of hGH-mediated metabolic disorders such as cancer and diabetes. Using such peptide mimetics of protein-protein interaction domains can help elucidate information on the binding of peptides to their conjugate binding protein. |
