BAG2 IN INFLAMMATION: INSIGHTS FROM HIGH RESOLUTION IMAGING

• Grant number: 25/00521-8
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: June 01, 2025
• End date: September 30, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Daniel Carneiro Carrettiero
• Grantee: Mariana Arsky Gomes
• Supervisor: Kenneth Kosik
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Institution abroad: University of California, Santa Barbara (UC Santa Barbara), United States
• Associated to the scholarship: 24/09041-6 - BAG2 AND THE IMMUNEPROTEASOME SYSTEM IN ALZHEIMERS DISEASE: FROM BIOINFORMATICS TO CELL CULTURE TESTING, BP.IC

Abstract

Tauopathies, including Alzheimer's disease (AD), are characterized by the accumulation of intracellular hyperphosphorylated TAU protein, leading to microtubule destabilization, neuronal death and cognitive decline. Proteasome plays a central role in its degradation, with studies suggesting a ubiquitin-independent pathway, involving the HSP70/BAG2 protein complex as an efficient pathway for TAU degradation. The BAG2 complex, in addition to the 20S proteasome core and PA28 cap, can condense forming phase-separated membraneless organelles, described by our group as "BAG2 condensates" in 2022. The PA28 cap is also necessary for antigen presentation in the major histocompatibility complex (MHC-1, HLA-A in humans). Proinflammatory signaling, such as IFN-¿ and TNF-¿, engages PA28 and alters the constitutive proteasome core, modifying its proteolytic properties and producing more immunogenic peptides. This could indicate that BAG2 condensates are involved in degradation and presentation of TAU peptides to the immune system, although the effects of IFN-¿ on the condensates are still unknown. To better understand the role of BAG2 and IFN-¿ in protein degradation and immune responses, this study proposes a colocalization testing with confocal microscopy for high resolution imaging. For this, we will perform immunofluorescence staining on H4 cell cultures, including wild-type and CRISPRi-mediated BAG2 knockdown models in response to IFN-¿ treatment, and confocal microscopy will be used to visualize key protein targets involved in protein degradation and immune responses, such as HLA-A and PA28¿ (subunit of PA28), colocalizing with BAG2 and TAU. This approach is expected to provide valuable insights into the mechanisms underlying TAU protein degradation mechanisms in AD and other tauopathies.