Gene: MAP1LC3B
UniProt: Q9GZQ8
Molecular Weight: ~17 kDa
Subcellular Localization: Cytosol, autophagosome membrane, lysosome
Protein Family: ATG8 family (LC3/GABARAP)
MAP1LC3B (Microtubule-Associated Protein 1 Light Chain 3 Beta) is a key protein involved in autophagy. It is essential for the formation of autophagosomes and has been heavily studied in the context of neurodegenerative diseases.
MAP1LC3B (Microtubule-Associated Protein 1 Light Chain 3 Beta) is a ubiquitin-like protein:
- N-terminal α-helical region: Contains the N-terminal hydrophobic pocket
- Ubiquitin-like domain: C-terminal domain with ubiquitin fold
- C-terminal glycine: Exposed after processing (LC3-I to LC3-II)
- LIR (LC3-interacting region) motif: Interacts with autophagy receptors
LC3 exists in multiple isoforms (LC3A, LC3B, LC3C) with similar functions.
LC3B is a central player in autophagy, the cellular degradation pathway essential for neuronal health:
- Autophagosome formation: LC3-II is conjugated to phosphatidylethanolamine (PE) on autophagosome membranes
- Cargo recognition: LC3 binds to selective autophagy receptors (p62, OPTN, NDP52) that recognize ubiquitinated cargo
- Membrane tethering: LC3 facilitates membrane fusion events during autophagosome formation
- Synaptic vesicle turnover: Autophagy regulates synaptic vesicle pools and neurotransmitter release
- Protein quality control: Clearance of misfolded proteins and damaged organelles
- Autophagy impairment: LC3-positive autophagosomes accumulate in AD brain, suggesting blocked autophagy
- Aβ clearance: Reduced autophagy leads to impaired Aβ degradation
- Tau pathology: Autophagy defects may contribute to tau aggregation
- Neuronal loss: Accumulation of autophagic vacuoles is a hallmark of AD neurons
- α-synuclein clearance: Autophagy via LC3 is important for clearing α-synuclein aggregates
- Mitophagy: PINK1/Parkin-mediated mitophagy uses LC3 for damaged mitochondria clearance
- LRRK2 interaction: Mutant LRRK2 impairs autophagy, including LC3 function
- Autophagy dysfunction: LC3 puncta accumulate in ALS motor neurons
- Protein aggregate clearance: Impaired selective autophagy leads to TDP-43 and SOD1 aggregate buildup
- Rab proteins: ALS-linked Rab39B mutations affect autophagy
- Mutant huntingtin clearance: Autophagy mediated by LC3 clears mutant HTT protein
- Aggregate formation: Autophagy impairment contributes to toxic aggregate formation
- Therapeutic potential: Autophagy enhancers reduce mutant HTT aggregation
- GCIs: LC3 accumulates in glial cytoplasmic inclusions
- Oligodendroglial dysfunction: Autophagy defects contribute to MSA pathogenesis
| Approach |
Compound |
Mechanism |
Status |
| Autophagy induction |
Rapamycin, everolimus |
mTOR inhibition |
Clinical trials |
| Autophagy enhancers |
Trehalose, carbamazepine |
mTOR-independent activation |
Research |
| Autophagy modulators |
Small molecule enhancers |
Increase LC3 lipidation |
Discovery |
| Gene therapy |
AAV-LC3 delivery |
Enhance autophagy |
Preclinical |
This page was created as part of the NeuroWiki protein page initiative for neurodegeneration research.