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Characterization of Neuronal Lysosome Interactome with Proximity Labeling Proteomics
Published on: June 23, 2022
A potentially dynamic lysosomal role for the endogenous TRPML proteins
David A Zeevi1, Ayala Frumkin, Vered Offen-Glasner
1Department of Human Genetics, Hadassah Hebrew University Hospital, Jerusalem, Israel.
The Journal of Pathology
|June 27, 2009
Summary
Mucolipin-2 (TRPML2) and mucolipin-3 (TRPML3) proteins, like mucolipin-1 (TRPML1), are essential for lysosomal integrity. Their depletion causes lysosomal storage, suggesting novel lysosomal storage disorder (LSD) pathologies.
Area of Science:
- Cell Biology
- Genetics
- Biochemistry
Background:
- Lysosomal storage disorders (LSDs) are inherited diseases caused by deficiencies in lysosomal proteins.
- Mucolipidosis type IV (MLIV) is an LSD resulting from mutations in the mucolipin 1 (TRPML1) protein, characterized by cellular accumulation of lipids and water-soluble materials.
- TRPML1 is known to interact with its paralogs, TRPML2 and TRPML3, in experimental systems.
Purpose of the Study:
- To investigate the role of TRPML2 and TRPML3 in maintaining lysosomal integrity.
- To determine if TRPML2 and TRPML3 share functional similarities with TRPML1 in lysosomal regulation.
- To explore potential novel LSD pathologies associated with TRPML2 and TRPML3 dysfunction.
Main Methods:
- Gene-specific knockdown assays were performed on TRPML2 and TRPML3.
- Ultrastructural analysis using electron microscopy was employed to examine cellular morphology.
- Co-immunoprecipitation assays were used to assess protein interactions.
- Confocal microscopy was utilized for co-localization studies of endogenous TRPML proteins.
Main Results:
- Knockdown of TRPML2 and TRPML3 resulted in lysosomal inclusions, similar to TRPML1 deficiency.
- Physical interactions between endogenous TRPML proteins were limited.
- Endogenous TRPML proteins showed only partial co-localization within lysosomal and extra-lysosomal compartments.
Conclusions:
- TRPML2 and TRPML3, along with TRPML1, appear to play a role in regulating lysosomal integrity.
- The limited interactions and partial co-localization suggest a dynamic regulatory mechanism.
- Depletion of TRPML2/3 may underlie previously undescribed forms of lysosomal storage disorders.
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