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Updated: May 23, 2026
Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease
Published on: April 4, 2018
The functional analysis of the CHMP2B missense mutation associated with neurodegenerative diseases in the
Jeong-Ho Han1, Hyun-Hee Ryu, Mi-Hee Jun
1Department of Biotechnology, College of Life Science and Nano Technology, Hannam University, 461-6, Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Republic of Korea.
Abstract:
Endosomal sorting complexes required for transport (ESCRTs) regulate a key sorting step of protein trafficking between endosomal compartments in lysosomal degradation. Interestingly, mutations in charged multivesicular body protein 2B (CHMP2B), which is a core subunit of ESCRT-III, have been identified in some neurodegenerative diseases. However, the cellular pathogenesis resulting from CHMP2B missense mutations is unclear. Furthermore, little is known about their functional analysis in post-mitotic neurons. In order to examine their cellular pathogenesis, we analyzed their effects in the endo-lysosomal pathway in post-mitotic neurons. Interestingly, of the missense mutant proteins, CHMP2B(T104N) mostly accumulated in the Rab5- and Rab7-positive endosomes and caused delayed degradation of EGFR as compared to CHMP2B(WT). Furthermore, CHMP2B(T104N) showed less association with Vps4 ATPase and was avidly associated with Snf7-2, a core component of ESCRT-III, suggesting that it may cause defects in the process of dissociation from ESCRT. Of the missense variants, CHMP2B(T104N) caused prominent accumulation of autophagosomes. However, neuronal cell survival was not dramatically affected by expression of CHMP2B(T104N). These findings suggested that, from among the various missense mutants, CHMP2B(T104N) was associated with relatively mild cellular pathogenesis in post-mitotic neurons. This study provided a better understanding of the cellular pathogenesis of neurodegenerative diseases associated with various missense mutations of CHMP2B as well as endocytic defects.
Insights
Mutations in charged multivesicular body protein 2B (CHMP2B) impact neurodegenerative diseases. The CHMP2B(T104N) mutation causes mild endo-lysosomal defects in neurons but doesn't significantly affect cell survival.
Area of Science:
- Cell Biology
- Neuroscience
- Molecular Biology
Background:
- Endosomal sorting complexes required for transport (ESCRTs) are crucial for protein trafficking and lysosomal degradation.
- Mutations in charged multivesicular body protein 2B (CHMP2B), an ESCRT-III subunit, are linked to neurodegenerative diseases.
- The cellular pathogenesis of CHMP2B missense mutations in neurons remains poorly understood.
Purpose of the Study:
- To investigate the cellular pathogenesis of CHMP2B missense mutations in the endo-lysosomal pathway of post-mitotic neurons.
- To analyze the functional impact of CHMP2B mutations on protein trafficking and degradation.
- To determine the effect of CHMP2B mutations on neuronal cell survival.
Main Methods:
- Analysis of CHMP2B missense mutant protein localization and function in post-mitotic neurons.
- Utilized Rab5 and Rab7 markers to track endosomal compartments.
- Assessed Epidermal Growth Factor Receptor (EGFR) degradation and autophagosome accumulation.
- Examined interactions with Vps4 ATPase and Snf7-2.
Main Results:
- CHMP2B(T104N) accumulated in Rab5- and Rab7-positive endosomes.
- EGFR degradation was delayed in neurons expressing CHMP2B(T104N) compared to wild-type (WT).
- CHMP2B(T104N) exhibited reduced association with Vps4 ATPase and increased association with Snf7-2, suggesting impaired ESCRT dissociation.
- Prominent autophagosome accumulation was observed with CHMP2B(T104N) expression.
- Neuronal cell survival was not significantly affected by CHMP2B(T104N).
Conclusions:
- CHMP2B(T104N) causes relatively mild cellular pathogenesis in post-mitotic neurons.
- The study enhances understanding of CHMP2B-associated neurodegenerative disease pathogenesis and endocytic defects.
- Findings highlight the specific cellular defects caused by CHMP2B mutations within the endo-lysosomal pathway.
