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Structural Basis for Small Molecule-Mediated Allosteric Activation of Protein Phosphatase 2A

小分子介导的蛋白磷酸酶 2A 变构激活的结构基础

基本信息

批准号：
10191568
负责人：
Ken Morita
金额：
$ 13.61万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-03 至 2021-07-15
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10191568
关键词：
3-Dimensional Acute T Cell Leukemia Advisory Committees Affinity Amino Acids Antipsychotic Agents Applications Grants Automobile Driving Binding Biochemical Biochemistry Biological Biological Assay Biology Cell Cycle Arrest Cells Chemicals Clinical Research Complex Crystallization Drug usage Energy Transfer Enzymes Family Fluorescence Fluorescence Polarization Fluorescence Resonance Energy Transfer Goals Grant Holoenzymes Human Immunoprecipitation Knowledge Label Leadership MYBL2 gene Malignant - descriptor Malignant Neoplasms Manuscripts Mass Spectrum Analysis Mediating Mentors Mentorship Mission Molecular Molecular Conformation Mutation Outcome Patient-Focused Outcomes Perphenazine Phosphoproteins Phosphoric Monoester Hydrolases Physiological Physiology Protein Family Protein phosphatase Proteins Proteomics Public Health Reporter Research Research Personnel Resolution Role Scientific Advances and Accomplishments Signal Transduction Pathway Specificity Structure Technology Testing Therapeutic Clinical Trial Time Toxic effect Training Tumor Suppressor Proteins Work Writing X-Ray Crystallography acute T-cell lymphoblastic leukemia cell analog anti-cancer therapeutic cancer cell cancer therapy career design fluorophore improved neoplastic cell novel novel strategies novel therapeutic intervention novel therapeutics overexpression protein activation protein function protein structure recruit response small molecule structural biology survival outcome three dimensional structure tool transcription factor tumor

项目摘要

The group of phosphatases collectively referred to as PP2A (protein phosphatase 2A) represent an important family of tumor suppressors. As a research fellow working under the mentorship of Dr. Thomas Look, the candidate has recently discovered that perphenazine (PPZ), a classic antipsychotic drug, and its related small molecule iHAP1 selectively drive the formation of heterotrimeric PP2A complexes containing the B56ϵ (PPP2R5E) subunit out of 15 possible distinct regulatory B subunits (K. Morita et al. Cell. 2020). Defining the structural mechanisms through which these small molecules allosterically activate PP2A with extreme specificity is of paramount importance because such knowledge will fundamentally advance the field of phosphatase biology, while forming the basis for medicinal chemists to optimize these tool compounds as novel anticancer therapeutics for clinical study. In this grant proposal, the candidate seeks to understand the fundamental mechanisms responsible for this allosteric activation of PP2A phosphatase from a structural perspective, working under the primary mentorship of Dr. Eric Fischer, an emerging leader in biochemistry and the field of structural biology. The central hypothesis is that PPZ/iHAP1 binds to the AC heterodimer and allosterically alters its conformation -- in ways that will be evident from the high-resolution crystal structure -- so that the B56ϵ subunit is readily recruited, thus driving the formation and activation of the PP2A-B56ϵ phosphatase in the cell. The immediate objectives are to determine the three-dimensional protein structures of the PP2A holoenzyme complexes formed in response to PPZ/iHAP, and to define the molecular contacts of the PP2A subunits with PPZ/iHAP compounds by X-ray crystallography. This goal will be pursued in two specific aims: 1) Determine the three-dimensional structure of the PP2A holoenzyme complex in the presence of PPZ or iHAP compounds to decipher the mechanisms underlying allosteric activation of specific PP2A subunit complexes by these small molecules, and 2) Determine the biochemical mechanisms underlying the ability of allosteric small-molecule PP2A activators to drive dynamic exchange of the PP2A regulatory B subunits with the AC heterodimer, from the Striatin family proteins in control cells to the B56ϵ or B55α proteins for iHAP/PPZ and SMAP, respectively. This strategy is significant because the results could reveal new mechanisms underlying allosteric activation of specific PP2A phosphatase complexes, which in turn will be key to dissecting the normal physiologic roles of this diverse family of phosphatases and to understanding their roles as tumor suppressors and how they are subverted in malignant transformation. This proposal has been designed to provide the candidate with advanced training in structural biology, as well as mentoring in manuscript/grant writing and leadership qualities. Bolstered by the guidance of a new primary mentor, Dr. Eric Fischer, together with the ongoing contributions of co-mentor Dr. Thomas Look, and the scientific advisory committee composed of experts necessary to complete this work, this proposal should significantly enhance the candidate's career goal of becoming an independent investigator.

这组磷酸酶统称为PP2A（蛋白磷酸酶2A）