Unravelling the mechanism of PAQosome assembly: a system involved in maturation of protein complexes

• Grant number: 22/01955-3
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): November 01, 2022
• Effective date (End): October 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal researcher: Carlos Henrique Inacio Ramos
• Grantee: Gabriel Zazeri
• Home Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

PAQosome (Particle for Arrangement of Quaternary structure) is a protein system with remarkable functions, which was recently discovered due to the discovery of its component functions. Its components include the R2TP complex (related to the name of the proteins Rvb1/2, Tah1 and Pih1) and prefoldin. This system is involved in the assembly and maturation of several multiprotein complexes in eukaryotes. In addition to prefoldin, R2TP interacts with the cellular chaperome via binding between Tah1 and HSP90 (90 kDa heat shock protein). Tah1 is the name of the protein in yeast organism, which has only 111 residues. The correspondent Tah1 protein in humans is named RPAP3, with 665 residues, whose sequence is longer than Tah1, due to the presence of domains not found in Tah1. Our research group and collaborators have published important results on the structure and function of the R2TP system in human and yeast. In this context, we aim to explore the differences between Tah1 and RPAP3, including the study of proteins from other organisms, since we have noted the increase of complexity verified mainly by the extension of the polypeptide chain and inclusion of domains of these proteins. The specific objectives of this project include the expression of recombinant proteins and the investigation of the PAQossome system by two perspectives: the first is the study of the RPAP3/Tah1 and HSP90 interaction by means of spectroscopic, calorimetric and computational techniques, we seek to describe the affinity constant, the thermodynamic parameters and the binding mode, in order to elucidate the mechanism by which HSP90 interacts with the different structures; the second is the conformational characterization of the oligomers formed by the RUVBL1/2 proteins of Aedes aegypt. The expected results have potential to increase our knowledge about this complex in particular. In a general way, the expected results have potential to reveal aspects of the assembly and maturation of protein complexes in the cell. (AU)