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A Versatile Pipeline for Analyzing Dynamic Changes in Nuclear Bodies in a Variety of Cell Types
Published on: June 28, 2024
FBXO25-associated nuclear domains: a novel subnuclear structure
Adriana O Manfiolli1, Ana Leticia G C Maragno, Munira M A Baqui
1Departments of Biochemistry and Immunology and Cellular and Molecular Biology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, São Paulo 14049-900, Brazil.
Molecular Biology of the Cell
|February 22, 2008
Summary
FBXO25 forms novel nuclear domains containing ubiquitin conjugates and proteasome components. This ubiquitin ligase activity prevents huntingtin protein aggregation, highlighting its role in nuclear quality control.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The Skp1-Cul1-Rbx1 complex forms the core of an SCF (Skp-Cullin-F-box) ubiquitin ligase.
- FBXO25 is a protein component of a functional ubiquitin ligase complex.
Purpose of the Study:
- To investigate the cellular distribution and localization of the FBXO25 protein.
- To characterize novel nuclear compartments associated with FBXO25.
- To explore the functional role of FBXO25-mediated ubiquitination in preventing protein aggregation.
Main Methods:
- Immunochemical and biochemical approaches were used to study FBXO25.
- Affinity-purified antibodies against FBXO25 were generated.
- Immunoblot analysis and confocal microscopy were employed to determine protein expression and localization.
- Cellular treatments included transcription inhibition (actinomycin D) and heat shock.
Main Results:
- FBXO25 protein is expressed in most mouse tissues, excluding striated muscle.
- Endogenous FBXO25 localizes to novel, dot-like nuclear domains distinct from known structures.
- These FBXO25-associated nuclear domains contain ubiquitin conjugates, 20S proteasomes, and Skp1.
- Nuclear FBXO25 organization is dynamic and influenced by cellular transcriptional activity.
- FBXO25-dependent ubiquitin ligase activity inhibits the aggregation of polyglutamine-huntingtin protein in HEK293 cells.
Conclusions:
- FBXO25 forms unique nuclear compartments involved in ubiquitin-proteasome system regulation.
- These dynamic nuclear domains are sensitive to cellular transcriptional states.
- FBXO25-mediated ubiquitination plays a role in preventing nuclear protein aggregation, potentially targeting huntingtin protein.
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