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Updated: Jan 31, 2026
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Characterization of Neuronal Lysosome Interactome with Proximity Labeling Proteomics
Published on: June 23, 2022
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Proximity-Based Phospho-Interactome (Prob-PhI) Characterization Reveals Distinct Signaling Activities of MEK1 and
Ying Wang1,2,3, Ping Xiao3,4, Ligang Fan5
1Shaanxi Provincial Key Laboratory of Infection and Immune Diseases, Shaanxi Provincial People's Hospital, Xi'an 710068, China.
Analytical Chemistry
|January 29, 2026
Summary
We developed a new method, proximity-based phospho-interactome (Prob-PhI), to identify kinase substrates. Prob-PhI revealed distinct roles for MEK1 and MEK2, with MEK2 uniquely phosphorylating LAMP3 to regulate lysosomal function.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Protein kinases regulate cellular functions via phosphorylation.
- Identifying kinase substrates is crucial for understanding health and disease.
- Current methods for substrate identification face challenges.
Purpose of the Study:
- To introduce the proximity-based phospho-interactome (Prob-PhI) platform for dissecting kinase interactomes and substrate profiles.
- To apply Prob-PhI to MEK1 and MEK2 to understand their distinct signaling roles.
- To identify novel substrates and functions of MEK1 and MEK2.
Main Methods:
- Developed and utilized the proximity-based phospho-interactome (Prob-PhI) platform.
- Employed the biotin ligase BASU for proximity-based labeling of interactors.
- Analyzed differential phosphorylation upon kinase inhibition to identify substrates.
- Applied Prob-PhI to MEK1 and MEK2 within the mitogen-activated protein kinase (MAPK) pathway.
Main Results:
- Delineated distinct interactomes and phosphoproteomes for MEK1 and MEK2.
- Identified lysosome-associated membrane glycoprotein 3 (LAMP3) as a specific substrate of MEK2.
- Demonstrated that MEK2 phosphorylates LAMP3 at threonine 201, modulating lysosomal function.
- Showcased the unique substrate specificities of MEK1 and MEK2.
Conclusions:
- The Prob-PhI platform is an effective method for mapping kinase signaling networks.
- MEK1 and MEK2 exhibit distinct substrate profiles and functional roles.
- MEK2-mediated phosphorylation of LAMP3 plays a role in regulating lysosomal function.
- Prob-PhI facilitates the discovery of kinase-specific substrates and their biological significance.
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