Influence of Domains and Post-translational Modifications on the Structure-Function Relationship of DNAJ Family Co-chaperones

• Grant number: 24/13266-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2024
• End date: February 29, 2028
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Carlos Henrique Inacio Ramos
• Grantee: Gabriel Rodrigues Martos
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 17/26131-5 - The chaperome: study of the relationship of the structure of its components and the maintenance of proteostasis, AP.TEM

Abstract

The maintenance of proteostasis is essential for the proper functioning of cellular processes. This balance is maintained by a complex system known as protein quality control (PQC), which encompasses a variety of metabolic pathways and components, such as HSP70. The HSP70 system performs various functions, such as assisting in the correct folding of newly synthesized proteins, translocation, and reactivation of aggregated proteins. HSP70 is a foldase with ATPase activity that promotes protein folding, being mainly assisted by co-chaperones of the HSP40/DNAJ family. DNAJ family proteins are characterized by the presence of a highly conserved J domain that interacts with and stimulates the ATPase activity of HSP70. These proteins comprise a class that includes very diverse proteins, distinguished by the presence of other variable domains, in addition to the J domain, involved in the recognition of target proteins and various modulations of HSP70 activity. These co-chaperones have been the subject of study for decades due to their fundamental role in maintaining proteostasis and their relationship with the development of various diseases related to incorrect folding and aggregation of proteins, particularly neurodegenerative diseases. Our group has been contributing to this knowledge base consistently for over 20 years. To further advance in this field, we propose to study the structure-function relationship of four HSP40 family proteins: human DNAJA1, DNAJB12, and DNAJB14, and Aedes aegypti DNAJA1. This study will be divided into two parts. First, the focus will be on the characterization of recombinant proteins, using appropriate techniques to understand the structure-function relationship and stability of the targets. In the second part, we will investigate the functional characterization of these proteins and their relationship with their cellular functions. This will include analyzing the effects of post-translational modifications and site-directed mutations, the capacity to protect against the aggregation of client proteins, the interaction of the studied proteins with HSP70, the study of the phenotype resulting from gene deletion in insect cells, among other aspects. The outlined objectives are highly relevant for understanding the role of the chaperone and co-chaperone network in the PQC system, as well as its impact on cellular homeostasis.