A wiring of the human nucleolus

Area of Science:

• Proteomics
• Systems Biology
• Molecular Cell Biology

Background:

• The human nucleolar proteome is extensively inventoried, but ~30% of proteins lack functional annotation.
• Understanding nucleolar protein function is crucial for deciphering cellular processes like ribosome biogenesis.

Purpose of the Study:

• To assign functions to uncharacterized nucleolar proteins using data integration and machine learning.
• To construct a draft map of the human ribosome biogenesis pathway.
• To explore the functional diversity of the nucleolus beyond ribosome biogenesis.

Main Methods:

• Integrated multiple data types with high-throughput proteomics.
• Employed a machine-learning approach to predict protein function and interactions.
• Assembled protein complexes to infer pathway involvement.
• Performed experimental validation for predicted nucleolar protein localization.

Main Results:

• Presented a draft of the human ribosome biogenesis pathway involving 74 proteins.
• Assigned functions to 49 previously uncharacterized nucleolar proteins.
• Identified protein complexes with functions beyond ribosome biogenesis.
• Experimentally confirmed nucleolar localization for 11 predicted proteins.

Conclusions:

• The integrated data-driven approach successfully assigned functions to uncharacterized nucleolar proteins.
• The study provides a foundational map of ribosome biogenesis and highlights nucleolar functional diversity.
• This methodology can be applied to other biological organelles and systems for functional annotation.