| Protein Name | MAP1LC3C (Microtubule-Associated Protein 1 Light Chain 3 Gamma) |
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| Gene | [MAP1LC3C](/genes/map1lc3c) |
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| UniProt ID | Q9BQI3 |
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| PDB ID | 2N8P, 2N8Q |
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| Molecular Weight | ~15 kDa |
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| Subcellular Localization | Cytosol, Autophagosome membrane, Lysosome |
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| Protein Family | LC3/GABARAP family |
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LC3C (MAP1LC3C) is a member of the microtubule-associated protein 1 light chain 3 (MAP1LC3) family, which also includes LC3A, LC3B, and LC3B2. LC3C is a core autophagy protein involved in the formation and maturation of autophagosomes, playing crucial roles in cellular homeostasis and protein quality control. Dysregulation of LC3C and the autophagy pathway has been implicated in several neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) [1].
¶ Domain Architecture
LC3C contains several key structural features:
- N-terminal region: Contains the ubiquitin-like fold domain that undergoes lipidation
- LIR (LC3-interacting region) docking site: Critical for binding to autophagy receptors
- C-terminal region: Contains the conserved glycine residue required for lipidation
LC3C undergoes several important post-translational modifications:
- Phosphorylation: LC3C can be phosphorylated at Ser12 and Ser24 by various kinases
- Lipidation: The conjugation of phosphatidylethanolamine (PE) to the C-terminal glycine creates LC3C-II, the membrane-bound form
- Acetylation: Regulates LC3C's autophagic function in response to cellular stress
LC3C is essential for autophagosome formation and serves multiple functions:
- Autophagosome nucleation: LC3C contributes to the recruitment of autophagy-related proteins to the phagophore
- Membrane expansion: Facilitates the expansion of the autophagosomal membrane
- Cargo recognition: Through LIR-mediated interactions, LC3C binds to autophagy receptors containing LIR motifs
- Selective autophagy: LC3C has specialized roles in selective autophagy pathways, including mitophagy and xenophagy [2]
In the central nervous system, LC3C is expressed in:
LC3C-mediated autophagy is crucial for:
- Synaptic plasticity and function
- Neuronal protein quality control
- Mitochondrial turnover (mitophagy)
- Axonal transport of damaged organelles
In AD, LC3C dysfunction contributes to disease pathogenesis through:
- Impaired autophagic-lysosomal pathway: Reduced LC3C lipidation and autophagosome formation leads to accumulation of amyloid-beta and tau aggregates
- Defective mitophagy: Impaired clearance of damaged mitochondria contributes to neuronal energy deficits and oxidative stress
- Synaptic dysfunction: Altered LC3C function affects synaptic protein turnover and plasticity [3]
LC3C plays a protective role in PD through:
- Mitophagy regulation: Critical for清除受损的多巴胺能神经元中的线粒体
- Alpha-synuclein clearance: LC3C-mediated selective autophagy contributes to removal of toxic alpha-synuclein aggregates
- Lewy body formation: Dysregulated autophagy may contribute to Lewy body pathology [4]
In ALS, LC3C dysfunction is implicated through:
- Protein aggregate clearance: Impaired autophagy leads to accumulation of TDP-43, FUS, and SOD1 aggregates
- Mitochondrial quality control: Defective mitophagy contributes to motor neuron degeneration
- Axonal transport defects: LC3C-associated transport dysfunction affects neuromuscular junction integrity [5]
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Autophagy enhancers:
- Trehalose: Natural disaccharide that enhances LC3C-mediated autophagy
- Rapamycin: mTOR inhibitor that promotes autophagosome formation
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Small molecule activators:
- Akt inhibitors that relieve mTOR suppression
- AMPK activators (e.g., metformin)
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Gene therapy approaches:
- Viral vector-mediated MAP1LC3C overexpression
- CRISPR-based editing to enhance LC3C expression
- Balancing basal autophagy with enhanced autophagy
- Tissue-specific delivery to the central nervous system
- Avoiding unwanted effects on other cellular processes
- Structure and function of LC3C in selective autophagy (2020)
- LC3C-mediated mitophagy in neuronal survival (2019)
- Autophagy dysfunction in Alzheimer's disease (2021)
- LC3 and alpha-synuclein: Implications for Parkinson's disease (2018)
- Selective autophagy receptors in neurodegeneration (2022)
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