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Updated: Sep 3, 2025
09:37
An Integrated Approach for Microprotein Identification and Sequence Analysis
Published on: July 12, 2022
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Mapping subcellular localizations of unannotated microproteins and alternative proteins with MicroID
Zhenkun Na1, Xiaoyun Dai2, Shu-Jian Zheng1
1Department of Chemistry, Yale University, New Haven, CT 06520, USA; Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT 06516, USA.
Molecular Cell
|July 29, 2022
Summary
Researchers developed MicroID, a new method using proximity biotinylation, to map the locations of unannotated microproteins and alternative proteins. This technique identified over 150 proteins associated with subnuclear organelles, revealing new functions in vivo.
Area of Science:
- Proteomics
- Molecular Biology
- Cell Biology
Background:
- Thousands of unannotated microproteins (<100 amino acids) and alternative proteins (alt-proteins) have been identified through proteogenomics.
- The subcellular localization and functions of these novel proteins are largely unknown but critical for understanding their roles.
- Proximity biotinylation is a powerful technique for defining protein composition within cellular compartments.
Purpose of the Study:
- To develop a high-throughput method for determining the subcellular localization of unannotated microproteins and alt-proteins.
- To apply this method to identify novel protein associations with subcellular organelles.
- To validate the utility of the method in a living animal model.
Main Methods:
- Development of a proximity biotinylation technology with TurboID, termed MicroID, for high-throughput mapping of microproteins and alt-proteins.
- Application of MicroID to identify proteins associated with subcellular compartments.
- In vivo validation in a mouse model to confirm the method's applicability and discover conserved proteins.
Main Results:
- MicroID successfully mapped over 150 microproteins and alt-proteins to specific subcellular localizations, particularly within subnuclear organelles.
- Identified a specific alt-protein, alt-LAMA3, localized to the nucleolus with a demonstrated function in pre-rRNA transcription.
- Validated the expression of a conserved nuclear microprotein in vivo using the MicroID approach.
Conclusions:
- MicroID is an effective high-throughput technology for discovering and localizing unannotated microproteins and alt-proteins.
- The study reveals novel associations of these proteins with subnuclear organelles and uncovers new functional insights, such as alt-LAMA3's role in transcription.
- MicroID provides a valuable tool for in vivo proteomic discovery, advancing the characterization of the proteome.
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