MAP1LC3B

Function

Ubiquitin-like modifier involved in formation of autophagosomal vacuoles (autophagosomes). Plays a role in mitophagy which contributes to regulate mitochondrial quantity and quality by eliminating the mitochondria to a basal level to fulfill cellular energy requirements and preventing excess ROS production (PubMed:28017329). While LC3s are involved in elongation of the phagophore membrane, the GABARAP/GATE-16 subfamily is essential for a later stage in autophagosome maturation. Promotes primary ciliogenesis by removing OFD1 from centriolar satellites via the autophagic pathway. Through its interaction with the reticulophagy receptor TEX264, participates in the remodeling of subdomains of the endoplasmic reticulum into autophagosomes upon nutrient stress, which then fuse with lysosomes for endoplasmic reticulum turnover (PubMed:31006538, PubMed:31006537).

Post-translational modifications

The precursor molecule is cleaved by ATG4B to form the cytosolic form, LC3-I. This is activated by APG7L/ATG7, transferred to ATG3 and conjugated to phospholipid to form the membrane-bound form, LC3-II (PubMed:15187094).

The Legionella effector RavZ is a deconjugating enzyme that produces an ATG8 product that would be resistant to reconjugation by the host machinery due to the cleavage of the reactive C-terminal glycine.

Phosphorylation at Thr-12 by PKA inhibits conjugation to phosphatidylethanolamine (PE) (By similarity). Interaction with MAPK15 reduces the inhibitory phosphorylation and increases autophagy activity.

Sequence similarities

Belongs to the ATG8 family.

Tissue specificity

Most abundant in heart, brain, skeletal muscle and testis. Little expression observed in liver.

Cellular localization

• Cytoplasm
• Cytoskeleton
• Endomembrane system
• Lipid-anchor
• Cytoplasmic vesicle
• Autophagosome membrane
• Lipid-anchor
• LC3-II binds to the autophagic membranes. LC3-II localizes with the mitochondrial inner membrane during Parkin-mediated mitophagy (PubMed:28017329). Localizes also to discrete punctae along the ciliary axoneme.

Alternative names

• Microtubule-associated proteins 1A/1B light chain 3B
• Autophagy-related protein LC3 B
• Autophagy-related ubiquitin-like modifier LC3 B
• MAP1 light chain 3-like protein 2
• MAP1A/MAP1B light chain 3 B
• Microtubule-associated protein 1 light chain 3 beta
• MAP1A/MAP1B LC3 B
• MAP1ALC3
• MAP1LC3B

Database links

• entrezGene:81631
• entrezGene:84557
• omim:609604
• omim:601242
• swissprot:Q9GZQ8
• swissprot:Q9H492

Target type

Proteins

Primary research area

Oncology

Other research areas

• Immuno-oncology
• Immunology & Infectious Disease

Molecular weight

14688Da