The regulation of the thermal stability and affinity of the HSPA5 (Grp78/ BiP) by clients and nucleotides is modulated by domains coupling

Author(s)

Silva, Noeli S. M. ; Siebeneichler, Bruna ; Oliveira, Carlos S. ; Dores-Silva, Paulo R. ; Borges, Julio C.

• Document type: Journal article
• Source: BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS; v. 1872, n. 5, p. 13-pg., 2024-07-18.

Abstract

The HSPA5 protein (BiP/Grp78) serves as a pivotal chaperone in maintaining cellular protein quality control. As a member of the human HSP70 family, HSPA5 comprises two distinct domains: a nucleotide-binding domain (NBD) and a peptide-binding domain (PBD). In this study, we investigated the interdomain interactions of HSPA5, aiming to elucidate how these domains regulate its function as a chaperone. Our findings revealed that HSPA5-FL, HSPA5-T, and HSPA5-N exhibit varying affinities for ATP and ADP, with a noticeable dependency on Mg2+ for optimal interactions. Interestingly, in ADP assays, the presence of the metal ion seems to enhance NBD binding only for HSPA5-FL and HSPA5-T. Moreover, while the truncation of the C-terminus does not significantly impact the thermal stability of HSPA5, experiments involving MgATP underscore its essential role in mediating interactions and nucleotide hydrolysis. Thermal stability assays further suggested that the NBD-PBD interface enhances the stability of the NBD, more pronounced for HSPA5 than for the orthologous HSPA1A, and prevents self-aggregation through interdomain coupling. Enzymatic analyses indicated that the presence of PBD enhances NBD ATPase activity and augments its nucleotide affinity. Notably, the intrinsic chaperone activity of the PBD is dependent on the presence of the NBD, potentially due to the propensity of the PBD for self-oligomerization. Collectively, our data highlight the pivotal role of allosteric mechanisms in modulating thermal stability, nucleotide interaction, and ATPase activity of HSPA5, underscoring its significance in protein quality control within cellular environments. (AU)

• FAPESP's process: 20/15947-7 - Mapping and mechanistic characterization of the interaction of the human HspA5 (BiP/Grp78/erHsp70) protein with the human Hep1 co-chaperone and with the Spike protein of the SARS-CoV-2 Coronavirus
• Grantee: Noeli Soares Melo da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/07206-6 - Studies of the mitochondrial HSP70 of human and protozoa: structural and functional approaches
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/14209-5 - Analysis and characterization of the n- and C- terminal domains of human BiP protein (HspA5)
• Grantee: Bruna Siebeneichler
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 17/26131-5 - The chaperome: study of the relationship of the structure of its components and the maintenance of proteostasis
• Grantee: Carlos Henrique Inacio Ramos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 12/50161-8 - Study of the structure and function of the Hsp90 chaperone with emphasis on its role in cellular homeostasis
• Grantee: Carlos Henrique Inacio Ramos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/16646-0 - Human mortalin: interaction with co-chaperones, p53 and mutants, aggregation kinectics, regulation/modulation and vesicle secretion
• Grantee: Paulo Roberto das Dores da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/07335-9 - Studies of human HSP70 isoforms residing in the cytoplasm and mitochondria and their high molecular weight oligomers: interaction with co-chaperones and client proteins
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants