CHMP5 (Charged Multivesicular Body Protein 5) is an ESCRT-III associated protein that plays a critical role in regulating [multivesicular body](/mechanisms/mvb-formation) (MVB) formation, [autophagy](/mechanisms/autophagy), and [endosomal trafficking](/mechanisms/endosomal-sorting). Proper functioning of the ESCRT machinery is essential for cellular protein homeostasis, and defects in ESCRT components have been increasingly implicated in neurodegenerative diseases [@christensen2020].
ESCRT Pathway and Cellular Function
The ESCRT (Endosomal Sorting Complex Required for Transport) machinery is responsible for:
Multivesicular body formation: Sorting ubiquitinated proteins into intralumenal vesicles
Autophagosome-lysosome fusion: Facilitating the degradation of cargo through autophagy
Membrane remodeling: Critical for endosomal maturation and trafficking
CHMP5 is a member of the CHMP (Charged Multivesicular Body Protein) family, which includes CHMP1-7. These proteins form the ESCRT-III complex that executes the final stages of MVB sorting [@fission2018].
CHMP5 in the ESCRT-III Complex
CHMP5 functions as part of the ESCRT-III machinery:
Interacts with other ESCRT-III components (CHMP2A, CHMP2B, CHMP4B, CHMP6)
Regulates the recruitment of accessory proteins
Modulates the scission of intralumenal vesicles
Role in Autophagy and Lysosomal Function
Proper autophagic flux is essential for neuronal health. CHMP5 contributes to:
Autophagosome maturation: Facilitates the fusion of autophagosomes with lysosomes
Endosomal-lysosomal pathway: Ensures proper trafficking of proteins to lysosomes
Protein quality control: Helps clear aggregated proteins that accumulate in neurodegeneration
Expression
CHMP5 is broadly expressed, with significant expression in:
[Hippocampus](/brain-regions/hippocampus) — critical for memory and learning
[Cerebellum](/brain-regions/cerebellum) — coordinates movement
Cortex
Peripheral tissues including hematopoietic cells
Disease Associations
Neurodegenerative Diseases
CHMP5 has been implicated in several neurodegenerative conditions through its role in [autophagy](/mechanisms/autophagy) and [endosomal sorting](/mechanisms/endosomal-sorting) [@lee2019]:
Alzheimer's Disease: Impaired autophagic-lysosomal pathway contributes to amyloid accumulation
Parkinson's Disease: Defects in endosomal trafficking affect [alpha-synuclein](/proteins/alpha-synuclein) clearance
ALS/FTD: ESCRT dysfunction linked to TDP-43 pathology