LC3B/MAP1LC3B

Autophagy is a crucial intracellular pathway that manages the degradation and recycling of long-lived proteins in the cell. The LC3 (or light chain 3) family is composed of three members, LC3A, LC3B and LC3C. Upon autophagy induction, LC3 is cleaved, causing the release of a C-terminal glycine that is required for phospholipid conjugation.  This process is vital to the formation of the autophagosome, a double membrane structure that delivers proteins to the lysosome during autophagy.

The human form of microtubule-associated protein light chain 3 (LC3) is expressed as 3 splice variants LC3A, LC3B, and LC3C.¹ LC3B is a subunit of the MAP1A and MAP1B microtubule-binding proteins and plays a central role in autophagosome membrane structure.

Microtubule-associated protein-1 light chain 3 (LC3/LC3B) is a ubiquitin-like protein involved in the formation of the autophagosome. It is homologous to the yeast Atg8 protein. Autophagosomes are important for the degradation and recycling of intracellular cargo such as misfolded proteins or damaged organelles. Upon induction of autophagy, LC3 is conjugated to the lipid phosphatidylethanolamine (PE) by the Atg12-Atg5-Atg16 protein complex.

Autophagy, also known as macroautophagy, supplies alternative fuel for cells that are under environmental stress conditions (including starvation, growth factor deprivation, and hypoxia). This highly regulated and catabolic cell process recycles and repurposes pre-existing organelles as well as existing macromolecules and is a very evolutionarily conserved and fundamental process to preserve cells under adverse conditions.