Exploring the biophysics/biochemistry of GRASPs from the causative agent of Chagas' disease and Amoebozoan D. discoideum

• Grant number: 25/04614-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: June 01, 2025
• End date: May 31, 2029
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Antonio José da Costa Filho
• Grantee: Beatriz Bezerra de Macêdo
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 23/04532-9 - The exquisite biophysics of the unconventional protein secretion: old and new looks to old and new problems, AP.TEM

Abstract

Golgi Reassembly and Stacking Proteins (GRASPs) are peripheral membrane-associated proteins initially identified for their role in the reorganization of Golgi cisternae. More recently, they have been implicated in unconventional protein secretion (UPS), an essential pathway for cellular homeostasis and stress responses. However, the precise molecular mechanisms governing GRASP function remain poorly understood. This project aims to expand our understanding of GRASPs by characterizing their biophysical and biochemical properties in Dictyostelium discoideum (DdGRASP) and Trypanosoma cruzi (TcGRASP), the causative agent of Chagas disease. By performing a comparative structural and dynamic analysis across different evolutionary branches of eukaryotes, we seek to explore their interaction promiscuity, conformational flexibility, and degree of intrinsic disorder, as well as their emerging role in the formation of biomolecular condensates. The potential impact of these structural features on the functional cycle of GRASPs is also a key focus of the project. To achieve these goals, we will combine spectroscopic and calorimetric techniques, X-ray crystallography, nuclear magnetic resonance (NMR), and membrane interaction assays to investigate the structural dynamics of these proteins and their propensity to undergo liquid-liquid phase separation (LLPS), forming biomolecular condensates. This study not only aims to unravel fundamental aspects of GRASP biology but may also provide valuable insights into novel therapeutic targets for infectious diseases. (AU)